Northeast Weather Blog

Historic October Snowstorm

By: sullivanweather, 10:35 AM GMT on October 29, 2008

Additional information on the historic October snowfall will soon follow. Pics are uploaded and will be posted here shortly.

Select snowfall amounts reported to local NWS offices.


Pennsylvania

Freeland - 17"
Bear Creek - 16"
Tobyhanna - 16"
Thompson - 14"
Moscow - 11"
Albrightsville - 6"
Philadelphia - Trace

New Jersey

High Point - 14"*
Lebanon - 12"
Mount Olive - 11.5"
Long Valley - 8"
Wantage - 4.5"

New York

Roxbury - 25.6"
Slide Mountain - 20"
Prattsville - 18.5"
Elka Park - 17"
New Kingston - 15"
Jefferson - 12"
Margaretville - 12"
Old Forge - 11"
Long Lake - 10"
Knox - 9"
Cobleskill - 9"
Huntersland - 8.5"
Bovina - 8"
Norwich - 7"
Adams - 7"
Parksville - 6.5"


Snowfall map of central New York and northeast Pennsylvania.




Current watches, warnings and advisories.


Eastern US current watches/warnings

------


Synopsis - Issued 10/29 @6:45am



Tuesday’s snowstorm has now moved into Canada but the upper trough will linger over the Northeast today bringing continued wintry weather. High pressure builds in to close out the week, then another cold frontal boundary brings temperatures back below normal this weekend, especially across the north. Jet stream moves north into Canada to begin next week, allowing for warmth via Chinook winds to build across the country into the region.


Short-term - Issued 10/29 @6:45am



The lake effect machine has been oiled and geared up for operation with the passage of Tuesday’s historic October snowstorm as cold winds from the Arctic pour down the backside of this system. Lake deltaT’s are currently 18-20°C, but shear is tempering intensity of the snow bands and spreading them out. Much of western Pennsylvania and western/central New York are seeing this lake effect activity early this morning and accumulations of 1-3 inches are possible by 9am. Additional steady light snows in a band over northern New York, western Massachusetts and Vermont is associated with the departing low and should end during the morning hours. Here, an inch or two of snow across the St.Lawrence Valley, Adirondacks, Berkshires, Green and White mountains will fall by mid-morning. Snow showers and flurries are making it down out of the mountains into the interior valleys, but these should not amount to much. Conversely, rain showers are moving through Maine early this morning in mild southerly winds ahead of the cold front yet to blast through. This frontal passage will occur this morning with mountain locations changing over to snow. Temperatures range from the upper 20’s to low 30’s across the interior of Pennsylvania, New York and western New England with mid to upper 30’s across the coastal plain. Eastern Maine will remain the warm spot with temperatures in the 40’s this morning.


Cold, moist cyclonic flow will continue throughout the day on Wednesday. In addition, minor mid-level shortwave disturbances will be rippling down the backside of the 500mb trough axis, enhancing the ongoing lake effect snow. Delta T’s will increase late this morning into the early afternoon to nearly 22°C, creating extreme instability and about 200-300 Joules of lake induced CAPE. Diurnal influences will disrupt bands into more cellular showers of snow that will extend rather far away from the lakes today given the decent levels of synoptic moisture in place and steep lapse rates across the region. Wind will oscillate on a 285-300° flow today, veering as vortices rotate through. Numerous snow showers will also be found across the higher terrain of northern New York and New England, especially north and west facing slopes. Snowfall amounts will be posted in a graphic later. Along the coastal plain skies will be partly to mostly cloudy. Some snow and/or rain showers may sneak down over the mountains but these will be brief and light. Temperatures will be 10-15 degrees below normal today with highs reaching only into the mid to upper 40’s along the southern coastal plain with mid 30’s to low 40’s across much of the remainder of the region. The higher terrain should remain below freezing all day long. Winds will be out of the west to northwest at 10-20mph and gusty. Strong southerly winds of 25-35mph with gusts to 50mph over Downeast Maine this morning will shift to the west after the frontal passage at 15-25mph with gusts to 40mph.

High pressure will begin build tonight, lowering inversions, drying the atmosphere and turning the flow anti-cyclonic. Lake effect snow showers will weaken, especially downwind of Lake Erie and skies will become partly cloudy to mostly clear away from the lakes and higher terrain of northern locales. Temperatures should drop into the 20’s across the interior and 30’s along the coastal plain. Highest mountain peaks will see temperatures drop into the teens.

Any lingering lake effect snow will come to an end during the day on Thursday. It will still be chilly, despite clearing skies and lighter winds, with highs about 5-10 degrees below normal.



Mid-term - Issued 10/29 @6:45am


High pressure slides by to the south on Friday and offshore, allowing for warm westerly winds to spread over the region. Temperatures will return to near normal with partly cloudy skies. A cold frontal boundary will enter the Northeast from Canada late Friday night and clear the coast by midday Saturday, dropping temperatures back below normal for this weekend. Some scattered showers may accompany this front, changing to snow after it’s passage, mainly across northern New York and New England. Lake response will be minimal, if any at all as core of cold advection moves over northern New England and high pressure quickly builds in.



Long-term - Issued 10/27 @6:45am



This high will move offshore and build into a strong ridge over the western Atlantic on Monday. Return flow of mild southwesterly winds will bring temperatures back to normal by Monday and above by midweek.


___________________________________________________________


Radar: Northeast Region Loop

NE radar


___________________________________________________________

Local SST's

Northeast SST's

Updated: 3:12 AM GMT on October 30, 2008

Permalink

Historic snowfall underway

By: sullivanweather, 10:48 AM GMT on October 27, 2008

Current watches, warnings and advisories.


Eastern US current watches/warnings

------


Synopsis - Issued 10/27 @6:45am


Great uncertainty in the short term as a sharpening upper trough dives into the Great Lakes/Northeast today, with a strong cold front along its eastern flanks, ushering in a continental polar airmass. Embedded within the upper trough is a vigorous mid-level disturbance, the energy in question, that will reach the Eastern Seaboard this evening, spawning low pressure along the slowing frontal boundary. As this low pressure rockets north towards New England on Tuesday, the potential for a significant early-season snowfall exists. Regardless of track, behind this low even colder air will funnel into the region in a northwesterly flow regime bringing much below normal temperatures and lake effect across the snow belts. Temperatures moderate under building heights and warm advection pattern into Halloween before another frontal passage this weekend gives the Northeast a pair of fair but chilly days to open November.


Short-term - Issued 10/27 @6:45am

**UPDATE UPDATE**


As expected, the 12z model suite has presented better consensus in low track and axis of heaviest precipitation now that the upper disturbance in question comes under a dense network of ob sites. Kudos to the NAM model for sniffing this one out 12-24 hours before the rest of the models; also the Euro for hinting at the possibility in the mid-term. Once again the GFS was great at picking up this pattern in the day 9 through 12 timeframe but lost the system in the medium range and was one of the last to find it in the short-term.

As inferred above, models consistently underestimated the vigor of the shortwave dropping into the deep trough now establishing itself across the eastern US. This upper trough is clearly defined on water vapor satellite loops, already neutrally tilted over the Ohio and Tennessee Valleys with a 130kt jet streak rounding its base over the Gulf Coast. Models also had gripes over their handling of the NAO teleconnection pattern this upcoming week, therefore any ensuing Greenland/Davis Strait blocking. This had previously caused a flatter representation of this trough as it passed through the Northeast, hence a weaker low forming well offshore. Now with the disturbance better sampled, and upstream issues resolved, it now appears that rapid cyclogenesis will occur east of Cape May this evening as the pocket of mid-level energy reaches the coast.


Upon forming, this low will take full advantage of the large-scale environment presented to it. A tight north-south low-level thermal gradient along the then stationary cold frontal boundary lined up along the New York-New England border will provide plenty of baroclinic energy for intensification. In addition, strong ascent associated with the mid-level vortmax rotating into the region along with a 130kt jet streak overhead, increasing upper divergence, low/mid level frontogenic forcing provided by 850/700/500mb lows closing off will make this storm a very efficient precipitation producer. With the overall trough tilting negative and eventually closing off, flow will back in from the ocean allowing for Atlantic moisture to be thrown back into the cold sector of the storm. Precipitation will blossom, and become heavy at times, across Long Island, southern New England and southeast New York this evening and expand north during the overnight. Tough call on the rain/snow line (if any) before midnight as the boundary layer seems too warm to support anything other than rain. But as better dynamics move over the region as we head into early Tuesday morning precipitation will begin to changeover to snow across the far interior, especially the higher terrain of the Poconos, Catskills and Adirondacks, mainly above 1500’. East of the Hudson River Valley, temperatures aloft are still to warm to support snowfall, so rain looks to be the dominate precipitation type.

During the day on Tuesday the surface low will move through western New England and into extreme northern New York, on a Hartford-Rutland-Plattsburgh line. As it moves along this path, its pressure is progged to drop from ~996mb to ~980mb. This rapid drop in pressure/increase in isobaric gradient will greatly increase the winds across the entire region. These winds will carry snow from northeast Pennsylvania to interior New York State west of the Hudson Valley as dynamic cooling processes and cold air advection along the southwestern flanks of the storm change any remaining rainfall over to snow. Strong frontogenic forcing due to the 850mb/700mb lows closing off will aid in this dynamic cooling process. Axis of heaviest snowfall will set-up to the immediate northwest of the track of the 700mb low, which will ride north up the Hudson Valley. The snow will be heavy at times and very wet, sticking to most exposed surfaces. Predominate oak and elm forests will be most susceptible to damage as these trees keep their leaves longer than most other deciduous trees, such as maples and birches, although should enough snow fall any tree would be at risk. Early call on accumulations is elevation dependent, with 6 inches or more at most locations above 2000’. 3-5 inches between 1500-2000’ and 2 inches or less below 1500 to the valley floors.

Further east, on the warm side of the storm, Tuesday will be rainy and windy. Snow will be confined to the highest elevations of the Green Mountains of Vermont and even this may end up being rain given the recent westward shifts with each ensuing model run. A 50-60kt 850mb low-level jet will develop over the Western Atlantic and slam into Downeast Maine. This surge of jet energy will promote the development of a band of heavy rainfall that should skirt eastern Maine as it pulls northwards but should mainly affect Nova Scotia. After the low passes north of one’s region and the cold front blasts through, winds will shift to the west and a changeover to snow may occur as heights/thicknesses crash. Valley locales shouldn’t see any accumulations, but the higher terrain of the Berkshires, Greens, Whites and the Litchfield Hills of northwest Connecticut may see wrap around accumulating snowfall extending into Tuesday night. Highest amounts will be found in Vermont, but a slushy inch or two may fall across the Berkshires before synoptic snows end.

Final snowfall outlook - updated!!



-------previous discussion-------


Fairly straight forward forecast today as a strong cold frontal boundary attempts to cross the region. Currently over central New York/Pennsylvania, this feature, in conjunction with a mid-level shortwave and a 140kt upper jet stream, is helping to produce some scattered showers along a line extending from the Laurel Highlands, across the Finger Lakes region, to the Adirondacks. As upper support quickly exits the region this morning into Canada, showers should become less numerous along the frontal boundary as it continues into eastern New York and western New England this afternoon. Along the frontal boundary will be varying levels of low/mid-level cloudiness with mainly clear skies out ahead of it. Behind the front a stratocumulus deck will likely develop by late morning from diurnal heating and added lake moisture, which may spit out a few sprinkles and/or flurries across the higher terrain. Towards the Great Lakes, cold advection pattern is already underway with lake-enhanced precipitation underway. Buffalo has been reporting occasional thunder with the lake effect rain showers there, as lake induced CAPE values are over 500J/kg. Delta T’s are already approaching 18°C as 850mb temps drop to –4°C by noon. Flow is currently out of the WSW but should turn more westerly then west-northwesterly this afternoon. This will cause lake bands to slowly settle southwards today. Close to the lake shores, precipitation will mainly be in the form of rain until cold air arrives behind a secondary surge or cold air tonight, but higher terrain away from the lakes will see precipitation slowly take on the form of snow. No accumulations are expected until the colder air arrives tonight, at least on the road surfaces. Highs today ahead of the front across New England will be in the 50’s and 60’s as one heads towards the coast. Behind the front temperatures should remain in the 40’s with 30’s possible across the higher terrain along the spine of the Appalachians. From eastern New York to western New England, where much of the day will be spent under the influence of the front, temperatures should rise into the 50’s with 40’s across the higher peaks of the Catskills, Berkshires and Adirondacks. Winds will be from the southwest ahead of the front around 5-15mph and turn more towards the west to west-northwest behind the front around 10-20mph.


Complications begin to arise tonight as a potent spoke of mid-level energy arrives along the Mid-Atlantic Coastline. Cyclogenesis will occur along the cold frontal boundary, which will have stalled out just off the coast and across New England by this time. This is about the point in time where model consensus breaks down and takes separate paths. Typically, I won’t get into breaking down each model, but with this level of uncertainty in the relative short term portion of the forecast, it’s worth exploring.

There’s basically three model camps this morning. One group of models, the NAM/WRF/NMM, are the strongest/slowest/furthest west with the development of this low pressure. These models take the low from a couple hundred miles east of the Delmarva, across the Twin Forks of Long Island and up the Connecticut River Valley, eventually backing the low to the northern Green Mountains by Tuesday evening as complex low occludes. To the east of the low pressure track strong, mild southerly winds will keep precipitation in the form of rain, which may fall heavy at times. Copious amounts of Atlantic moisture would be drawn into the system as a 50-60kt low-level jet develops over the western Atlantic and slams ashore Downeast Maine. The whole upper trough tilts negative and cuts-off, drawing this Atlantic moisture back into the cold sector of the storm. Deformation banding sets up across the Catskills, Hudson Valley and Adirondacks along the backside of the storm, dropping heavy amounts of wet wind-driven snow. Significant accumulations of snow will occur across the higher terrain where precipitation-type will be largely in the form of snow. Across valley locales where temperatures in the boundary layer start off warmer, it will take some time before dynamic cooling of the column allows snow to reach the surface, but eventually it will allowing for minor accumulations. QPF from these models is quite impressive, with widespread 1-2” amounts within the cold sector. In places where snow is the dominant precipitation type, up to a foot of heavy wet snow will occur. Over the western portion of the region there won’t be any synoptic precipitation from this system but the lake effect machine will be in gear as cold air advection continues to pour down the backside of the trough. 850mb temps drop to –6°C to –8°C by Tuesday afternoon, allowing for accumulating snow across the snowbelts, although precipitation may still be mixed with rain along the immediate lake shores.


On the other extreme are the solutions offered by the UKMET/NOGAPS, which shows a much more progressive trough and any development occurring too far offshore and remaining weak enough to spare much of the region of a significant storm. Some mixed precipitation will move across Maine and other portions of northern New England, but the main slug of precipitation moves over the Canadian Maritimes and the storm bombs out much too far away for anything more than lake-effect/upslope precipitation. With most models trending towards a solution closer to the coast the UKMET/NOGAPS solution will be ignored.

The GFS, ECMWF, SREF mean and Canadian model suite have more of a middle of the road approach, taking low pressure on a track about 40-70 miles east of the solutions offered by the NAM, WRF and other short range HiRes models. Despite the disagreement in track, each of these models agree with the prior solutions in intensity of the low pressure as it heads into New England on Tuesday; ~985mb, although the difference occurs with the timing, about 6 hours later. Also, like the NAM/WRF model solution, a strong deformation band of precipitation develops along the backside of low pressure, likely along the tightest 850-700mb thickness gradient where strong mid-level frontogenesis sets up, which is found over the New York-New England border region. Higher elevations, generally above 1500 feet, should see mainly snow from this band. Lower elevations will have to deal with a warmer boundary layer, and will have to wait for dynamic cooling of the column to begin in earnest, likely when the 700mb and 850mb low closes off Tuesday afternoon. Precipitation amounts from the GFS/Euro/Canadian models are also about 50-75% of those offered by the NAM/WRF models, generally .5-1.25” of QPF. In the cold sector where much of the precipitation falls as snow (higher terrain) up to 6 inches of snow may fall, with lesser amounts below 1,500’ and little, if any, accumulations across the valleys south of the Capital District (Albany).


While model differences remain, many similarities between the differing solutions have increased confidence of a major early-season snowstorm to move over the Northeast beginning late tonight extending into Wednesday morning. The main areas to be affected are the high elevations of eastern New York and western New England, although the axis of heaviest precipitation is yet to be determined. Valley locations will see snow from this system as well, but will likely be only minor accumulations or non-accumulating snow. The snow will be wind-driven and wet, and may take down trees and/or power lines. The east side of the storm will be in the warm sector, with heavy rain and strong coastal gales. Lake effect will increase late Tuesday as well, as colder air filters down across the region and better synoptic moisture in the wrap-around move overhead. At this time a blend of the NAM/WRF and the GFS/Euro/Canadian solutions will be the best way to go until more definitive model consensus, likely the 12z runs, develops. Updates to the forecast today are likely and perhaps some graphics.


Mid-term - Issued 10/27 @6:45am


The low wraps up over Quebec on Wednesday and lifts away from the region. Lingering lake-effect/upslope snow showers will continue across the Northeast in moist cyclonic flow. Skies will be mostly cloudy with areas along the coastal plain seeing the most breaks of sun. Temperatures will continue to average around 10 degrees below average with a biting northwesterly wind continuing to blow around 10-20mph.


Long-term - Issued 10/27 @6:45am


High pressure slowly builds just south of the region Wednesday night and Thursday. This should effectively end the chances for precipitation as drier air and anti-cyclonic flow gradually move into the region. Skies will clear and winds will calm. 850mb temperatures will be running from –4°C to –10°C from southwest to northeast. Should sufficient snowfall stick around, Wednesday night could easily be the coldest night of the year for many, especially should winds decouple as near perfect radiational cooling conditions would then develop. Moderating trend begins Thursday morning as heights aloft build, surface high slides offshore and 850mb temperatures moderate some 4-6°C over 12 hours. Warm advection pattern should bring in varying levels of mid/high level cloudiness but otherwise, a fair day.

Fair skies with seasonable temperatures return by Halloween for the trick-or-treaters. Any snow leftover should have largely melted, except for the highest mountain peaks. A cold front enters the Northeast this weekend, bringing chances for light showers lowering temperatures to slightly below average for early November.



Radar: Northeast Region Loop

NE radar


___________________________________________________________

Local SST's

Northeast SST's

Updated: 5:59 PM GMT on October 28, 2008

Permalink

Significant rainfall this weekend

By: sullivanweather, 8:56 AM GMT on October 23, 2008

Current watches, warnings and advisories.


Eastern US current watches/warnings

------


Synopsis - Issued 10/23 @5:00am

A large dome of strong high pressure will move across the Northeast over the next 36-48 hours bringing rather tranquil weather to the region. Conditions deteriorate on Saturday as a complex area of low pressure works it way into the region from the southwest, bringing the first significant rainfall since Kyle in late September. A strong cold front, associated with an anomalously deep upper trough, move into the Northeast on Monday and slow its eastward progression as additional energy rounds the base of the trough, perhaps spawning a coastal low. Lots of time to watch the developing evolution of these features that could bring another early season snowfall to the Northeast, especially over the elevated terrain. Cold, moist cyclonic flow in the upper trough axis will trigger more lake effect behind the departing low, which will lift out by Thursday allowing for a zonal flow to develop across the contiguous US and a return to normal temperatures.


Short-term - Issued 10/23 @5:00am



Sprawling dome of strong high pressure, ~1040mb at the surface, will be the dominating feature over the next couple days here in the Northeast. Despite brilliant sunshine today, the airmass in the boundary layer is still rather chilly and sinking air provided by high pressure should limit mixing. 925mb temperatures this afternoon will range from –1°C along the US-Canadian border to nearly 4°C along the Mason-Dixon line. This will translate to highs in the 40’s across the north (30’s above 2500’), with 50’s across the coastal plain and interior valleys south of I-90. Winds will be light and variable except for over Maine and coastal southern New England where a northwesterly to northerly breeze of around 10-15 mph will continue. Winds will quickly go calm tonight. Under the combination of those calm winds and clear skies, ideal radiational cooling conditions will be met. Freeze watches are up for coastal southern New England, extreme southeastern New York, and most of central/southern New Jersey where the growing season will be in jeopardy of ending. Lows will fall into the 20’s across most interior locales, except for along the immediate lakeshores of Erie and Ontario. Sheltered mountain valleys will have no trouble falling into the teens, either. Freezing temperatures should penetrate down to the southern New England coast and outlying areas of New York City, as well. The only locales not to be touched by a freeze tonight will be along the immediate Jersey shore, urbanized areas of Long Island and within the urban centers of Boston, New York and Philadelphia but a frost is still possible.

High pressure moves to the coast on Friday and the airmass moderates slightly, allowing afternoon highs to approach normal readings. Skies will continue to be filled with brilliant sunshine although high clouds may enter western sections during the early to mid afternoon ahead of an approaching trough. Temperatures will be, on average, about 5-8 degrees warmer than today. 50’s will move back into most of the interior with 40’s confined to the higher terrain and perhaps extreme northern Maine. Across the coastal plain highs may even climb into the low to mid 60’s. Light and variable winds will begin to shift to a more southerly direction as the afternoon progresses.

Clouds will continue to increase Friday night, lowering and thickening as the night progresses. Rain should break out by midnight along, and to the west, of the spine of the Appalachians up to the Niagara Frontier in response to a surge of isentropic lift. This shield of precipitation will advance into the remainder of Pennsylvania and move as far east as the Mohawk Valley in north-central New York by daybreak. Elsewhere, from eastern New York into New England, should remain precipitation-free into the overnight. Here clouds will also move in later in the overnight, so temperatures will quickly drop after dusk before leveling off as the clouds move in. Lows here should fall back into the mid 20’s across the coldest locales to the mid 30’s. Further west, the increase in clouds, commencement of precipitation and milder airmass should keep temperatures from falling as far as Thursday night’s lows. Here, mainly 40’s are to be expected. Winds will increase out of the south and southeast to 10-15mph.


Mid-term - Issued 10/23 @5:00am



Cut-off low pressure in the mid/upper atmosphere over the Ohio Valley begins to open up and take on a negative tilt as it approaches the Northeast on Saturday. In addition to this low pressure, the southerly flow out ahead of the trough will help to pick up a tropical disturbance, 91L, currently over the Western Caribbean and the southern Gulf of Mexico. This deeper tropical moisture will be funneled north, up the East Coast, on a 40-50kt low-level jet nosing into the Northeast. Precipitable water values rise to twice than climatology across a good portion of the region as the tropical moisture arrives. This system will be an efficient rainfall producer due to strong PVA associated with the mid-level vortmax that will bisect the region, good jet dynamics being in the left front exit region of a 120kt jet streak, and strong low-level forcing along a strong cold front. Conditions are also in place for the potential of a forced line of low-topped convection along the cold front. SREF means show a couple hundred joules of CAPE sneaking into eastern Pennsylvania, New Jersey and southern New York State during the afternoon and evening hours on Saturday. Should this convection develop, some of the stronger winds aloft may get mixed down to the surface. This storm quickly lifts into New England Saturday night and Sunday with rapid drying behind the frontal boundary. Instability parameters will be lost by Sunday and the threat of convection will wane. However, the heavy rain threat will remain with this system as it pushes into New England. Widespread 1-2 inch rainfall totals are to be expected with this storm as it pulls through the region. This amount of rain won’t be a flooding concern due to the recent spell of dry weather, however, nuisance flooding due to ponding of water on roadways and in parking lots where storm drains become clogged with fallen leaves may be a concern. An inch to an inch and a half of rainfall may fall in a relatively short period of time given the dynamics associated with this storm and the rather juicy airmass that will advect into the region out ahead of it. Wind will also be an issue, especially across coastal New England where a 50-60kt low-level jet @850mb will be blowing just overhead. It will take some time to break the inversion, but once the heavier precipitation starts some of these winds will be mixed down into the boundary layer. When this occurs 20-30mph winds with gusts as high as 50mph will develop. Behind the front winds will blow around 15-25mph with higher gusts in the cold air advection.

The storm moves into central and northern New England on Sunday while the remainder of the region dries out. It will be rather breezy behind the departing low, but partly sunny skies and mild temperatures should counteract the wind. Temperatures will rise into the 50’s and 60’s region-wide, with the 50’s concentrated across the north and into New England under the clouds and precipitation but 60’s elsewhere. A much better outlook for the second half of this weekend now than what was apparent just a couple days ago, so enjoy it!


Long-term - Issued 10/23 @5:00am


Big changes are to occur in the long-term as an anomalously deep upper trough carves itself out over the eastern half of the country. A vigorous mid-level disturbance/surface low couplet will move across southern Canada, sending a secondary strong cold front into the Northeast on Monday. Clouds and a few light showers will accompany this moisture-starved feature. Additional shortwave energy dropping down the backside of this trough will slow its eastward progression and sharpen it as it approaches the East Coast. Here’s with the situation gets a little hairy. As this energy rounds the base of the trough it will spawn an area of low pressure along, or just off, the East Coast Monday night into Tuesday. Initially positively tilted, the trough will make an attempt to tilt negative, which could hug this low closer to the coast bringing the potential for another significant East Coast storm. This remains a low probability scenario, but just thought I’d throw it out there. Most likely scenario is a cold frontal passage with any offshore low development happening too far into the Atlantic to bring any significant precipitation. Behind the front the coldest airmass of the season will blast into the Northeast, initiating the lake effect machine in what should be the first significant lake effect snowfall of the season. Lake effect gradually winds down by Wednesday as high pressure builds and airmass modifies. Deep upper trough will lift north of Hudson Bay by Thursday and Friday, bringing a zonal flow across the contiguous US and a return to milder temperatures.



___________________________________________________________


Radar: Northeast Region Loop

NE radar


___________________________________________________________

Local SST's

Northeast SST's

Permalink

Seasons' first snowfall for the Northeast

By: sullivanweather, 1:02 PM GMT on October 21, 2008

Current watches, warnings and advisories.


Eastern US current watches/warnings

------


Synopsis - Issued 10/21 @6:00am


Low pressure will cross the Northeast today and will be accompanied by a strong cold front that will usher in the coldest airmass of the season to date and provide a minor snowfall across the higher terrain of the North Country. High pressure will center itself over the region Wednesday through Friday, bringing fair skies and a gradual warming trend. Slow-moving cut-off low pressure will move from the Mid-Mississippi Valley to the Mid-Atlantic over the weekend spawning a coastal low pressure system that will bring the region’s first significant rainfall since September. Much colder air will invade the Northeast behind this storm to begin next week.


Short-term - Issued 10/21 @ 6:00am


A sharp trough of low pressure will move from Southern Ontario to the New England Coast over the next 18-24 hours. Showers have already broken out in advance of this feature across central Pennsylvania to the Adirondacks and will continue to push eastwards throughout the daylight hours, into western New England by noon, and to the coast by this evening. There may be a few sleet pellets this morning mixed in with the rain across some of the sheltered valleys of eastern New York State where temperatures have dropped below freezing and dewpoints remain in the 20’s. This will be very short-lived as mild southwesterly flow should quickly warm temperatures and dewpoints within the boundary layer to above freezing, likely as the precipitation begins. The ground is still warm so freezing rain will not be an issue. Temperatures today will warm into the 50’s for most locales, except northern New England where 40’s will suffice. Behind the cold front slicing through the region temperatures will follow an atypical diurnal pattern, likely holding near steady immediately following the frontal passage before slowly falling through the mid and late afternoon into the upper 30’s, especially across the higher terrain of northern New York and New England. Here precipitation will likely changeover to snow by dusk.

500mb low pressure makes it to the coast tonight, energizing the surface low, which will be just east of Cape Cod after midnight. This will act to increase the onshore flow to the north of the low and throw back some additional Atlantic moisture over New England. Cold air advection behind the low and dynamic cooling of the column should lower snow levels to under 1,000’ by daybreak across a large portion of New England. Cyclonic flow, added lake moisture and an inverted trough developing on the backside of the surface low should bring an accumulating snowfall to the Adirondacks, Greens, Whites, northern Catskills and Berkshires. Accumulations will be light, generally an inch or two but some of the higher peaks of the Green and White Mountains, as well as extreme northern Maine, may see as much as 3 to 4 inches. Additional non-accumulating snow showers will persist downwind of Erie and Ontario. With cloud cover, temperatures are not expected to plummet, despite the cold airmass advecting into the region. Overnight lows will fall to the upper 20’s to low 30’s across the interior with mid 20’s across the higher peaks. Along the coastal plain to southern New England temperatures will remain in the 40’s, with 30’s along the northern coastal plain north of Boston.

Upper trough axis will be over the Northeast Wednesday morning as the offshore low pressure system organizes in the Gulf of Maine. An inverted trough at the surface will hang back over central New England during the morning hours that could keep steady precipitation over coastal New England. Questions remains as to how much the boundary layer will cool, which may allow for a changeover to snow to occur almost to the coast. Interior sections of New England at elevations above 500’ most of the precipitation in the morning will fall in the form of snow that should accumulate above 1,000’. Meanwhile, to the west, lake-effect snow showers will be scattered about central New York State with upslope snow showers persisting across the Adirondacks of northern New York and the Greens and Whites across Vermont and New Hampshire. Additional accumulations of an inch or so before the snow winds down during the afternoon can be expected with little accumulations from the lake effect across central New York. Offshore low pressure will gradually move towards the Canadian Maritimes, pulling the inverted trough along with it. This should effectively end any steady precipitation by early afternoon but scattered showers of rain and snow will continue in the cyclonic flow behind the departing low. Any lake effect precipitation will end during the afternoon hours as well as a large dome of high pressure builds into the Northeast from the Great Lakes. Temperatures will struggle to climb much from their morning readings with continued cold air advection occurring throughout the remainder of the day. Most interior locales will not get out of the 40’s with 30’s expected across the higher terrain. Along the southern coastal plain temperatures may crack 50°F for a few hours before falling back into the upper 40’s by mid afternoon. Gusty northwest winds will also blow, especially across New England, as they will be closest to the departing low adding a winter-like nip to the air. Wind chills across northern New York and New England may remain in the 20’s for much of the day.

Aforementioned high will continue to build Wednesday night, bringing clearing skies and light winds over the western half of the region as cyclonic flow continues over New England where clouds and maybe even a few snow showers will be ongoing, especially across the higher terrain of northern Vermont, New Hampshire and Maine. Interior sections under the high should see their temperatures easily fall into the 20’s with teens possible across the higher terrain. Coastal locations should see lows drop into the 30’s along with interior southern New England due to lingering clouds.


Mid-term - Issued 10/21 @ 6:00am


Deep-layer ridging remains anchored over the Northeast Thursday and Friday leading to mainly fair skies and a warming trend as the airmass moderates. The nights should remain frosty as ideal radiational cooling conditions will be in place but this should matter little as most locations away from the immediate coast has already seen an end to their growing season. Temperatures will range from the 20’s and 30’s for low with 40’s and 50’s for highs Thursday. Friday will be 5-8 degrees warmer.



Long-term - Issued 10/21 @ 5:00pm


Deep-layer ridge moves offshore into the Western Atlantic Friday night and Saturday morning, giving way to a complex low pressure system that will bring the region's first significant rainfall in quite some time. This vertically stacked low pressure will slowly traverse the eastern US during the second half of this week, moving to a position over the central Appalachians by Saturday afternoon. Upon reaching the Mid-Atlantic the upper trough will begin to take on a negative tilt as the surface low rides north towards Ontario and attending frontal boundary occludes. Tightening pressure gradient between approaching low and strengthening ridge over the Western Atlantic will bring a strong southeasterly jet over the Northeast, transporting copius amounts of Atlantic moisture into the region. Rainfall amounts over the rgion should easily reach over an inch, especially in upslope areas favored in southeasterly fetch. Lesser amounts are to be expected over western sections away from the Atlantic moisture source. Occluded front pushes into New England on Sunday bringing most of the heavy rain with it. Behind the front some clearing skies should prevail for a few hours before a secondary cold front, associated with an unseasonably chilly airmass, crosses through Pennsylvania and New York during the late afternoon and early evening hours. 850mb temps rapidly drop behind this front to -4°C to -6°C, activating the lakes once again. Cold, moist cyclonic flow will continue Monday and Tuesday with scattered lake effect/upslope rain and/or snow showers (precip-type elevation/diurnal dependent). Models diverge midweek with GFS going to a more zonal flow and return to near normal temperatures while ECMWF model keeps deep upper trough in place over the eastern US with generally unsettled weather and below normal temperatures as we head into November.


___________________________________________________________


Radar: Northeast Region Loop

NE radar


___________________________________________________________

Local SST's

Northeast SST's

Updated: 9:04 PM GMT on October 21, 2008

Permalink

First taste of winter this week (and next??)

By: sullivanweather, 6:03 AM GMT on October 19, 2008

Current watches, warnings and advisories.


Eastern US current watches/warnings

------

Synopsis - Issued 10/19 @2:00am

A seasonably cold week for the Northeast, featuring the end of the growing season for most areas away from the immediate coast and the seasons’ first snowfall for many of the hills and mountains across the interior. Temperatures will slowly moderate after midweek as ridging builds and temperatures aloft warm.



Short-term - Issued 10/19 @2:00am

Sunday will be dominated by high pressure, bringing mostly sunny skies across the region except the immediate coastal areas where varying levels of mid and high cloudiness will persist a good portion of the day. Offshore, an area of low pressure has developed off the Carolina Coast and should move out to sea far enough away from the region to spare us precipitation but close enough to bring in some clouds. However, the sharpening gradient between the high over New England and the low in the Western Atlantic should kick up a stiff breeze across the coastal plain, especially over Cape Cod where wind gusts could approach 35mph. Given the very dry airmass in place, dead vegetation/fallen leaves, persistent wind above 15mph and the lack of any recent rainfall, there will be an enhanced wildfire risk across extreme southeastern New England today. Please be careful with any campfires, cigarette butts and burn pails and, if possible, postpone any burning to a later date. Winds shouldn’t an issue further inland under the low-level ridge axis will provide plenty of subsidence. There may be a few high clouds that stream in during the afternoon ahead of a system advancing into the northern Lakes but for all intents, a fine day. It will be a little on the cool side, despite the sunshine, with temperatures only climbing into the 40’s and low 50’s across the interior with mid to upper 50’s along the coast. Out on the Cape, the wind will add more of a bite to the air and should also kick up the surf. Wave heights will be increasing as the day wears on and Sunday night’s high tide cycle may see some overwash.

High pressure remains firm Sunday night, allowing for ideal radiational cooling conditions once again. There may be some high clouds that continue to filter into the region, but these should do little to halt the fall in temperatures. Once again, the higher terrain of northern New York and New England will drop into the upper teens to mid 20’s. Elsewhere across the interior upper 20’s to low 30’s will lead to another frosty night. Along the coastal plain and urban centers, temperatures will be milder, in the mid 30’s to low 40’s, but scattered areas of frost will dot the normally colder locales. It will be another night to protect the tender vegetation.

No big changes in the overall synoptic pattern on Monday, with oceanic storm continuing to spin a few hundred miles off the coast and a narrowing ridge axis overhead. Temperatures aloft will warm a few degrees and there will be a greater coverage of high clouds as the Great Lakes shortwave approaches. At the surface, temperatures will also be several degrees milder than those of this weekend, with most interior locales breaking 50°F, excluding the higher terrain. Along the coast, a light northerly flow will downslope from the surrounding terrain, leading to highs in the upper 50’s to mid 60’s, almost average for this time of year. Drivers beware during the late afternoon as the lower sun angles and increase in high cloudiness will greatly increase glare.


Mid-term - Issued 10/19 @2:00am


Aforementioned trough moves into the Northeast Monday night and Tuesday, sending a sharp cold front through the region. This very energetic system won’t have much moisture to work with, moving into the dry airmass over the region, but will still be able to squeeze out PVA driven showers, some with convective cores that may produce some graupel, especially over the higher terrain. Behind the cold front, strong cold air advection will quickly activate the lakes and make for rather gusty winds. Lake-effect rain showers should develop during the afternoon across interior New York and northwest Pennsylvania. This lake effect precipitation may transition over the snow Tuesday night as boundary layer cools with loss of daytime heating. High pressure will quickly be moving in to squelch out the lake effect, but not before some of the hilltops away from the lakes receive a coating. The low will be moving into the Canadian Maritimes but cyclonic flow will keep precipitation going across the higher terrain of northern New England, in the form of snow. Locations above 2,000’ may pick up an inch or two.

High pressure continues to build into the Northeast on Wednesday but an inverted trough hanging back off Tuesday’s low may bring a light snowfall to Downeast Maine during the morning hours. This will need to be watched. Otherwise, it will be a fair day for most with a definite chill in the air. High’s will only struggle into the 30’s across the northern interior and may not climb above freezing across the higher terrain of the Adirondacks, Greens, Whites and Presidential ranges. The remainder of the interior will see highs only in the low to mid 40’s with a 50°F reading or two possible along the coast. Skies clear and winds calm Wednesday night as high moves overhead in what should easily be the coldest night of the season. Freezing conditions should make it right down to the coast across New England and deep into the remainder of the coastal plain, sparing only the urban centers. A slight moderation Thursday with high pressure overhead, continuing to provide clear skies and light winds.



Long-term - Issued 10/19 @2:00am


Ridging hangs on for one more day, Friday, before sliding offshore to give way to a slowly advancing cut-off low pressure that should spread a significant rain event into the Northeast by next weekend. Models are hinting at a possible tropical connection that could bring the month-to-date’s paltry precipitation totals to near normal, ending the recent dry spell. A strong Greenland block may develop to close out the month, forcing the development of a deep eastern US trough. Stay tuned, but there may be a “White Halloween” for trick-or-treaters this year.



___________________________________________________________


Radar: Northeast Region Loop

NE radar


___________________________________________________________

Local SST's

Northeast SST's

Permalink

Pattern change upcoming

By: sullivanweather, 11:25 AM GMT on October 14, 2008

Current watches, warnings and advisories.


Eastern US current watches/warnings

------

Synopsis - Issued 10/14 @7:25am


A large deep-layer ridge remains parked over the Tennessee Valley, continuing to pump unseasonably mild weather into the Northeast on a westerly to southwesterly flow. The backdoor front advertised in my previous blog never materialized due to the eastward shift in the ridge axis over the eastern half of the country, keeping the Western Atlantic cut-off low pressure several hundred miles east of prior reasoning. In addition, the faster ejection of the western states winter storm should send what’s left of that trough through the region this afternoon and tonight, bringing nothing more than an increase in clouds and perhaps a few widely scattered showers. One last day of indian summer on Wednesday before it all comes to an abrupt end as low pressure moves into the region on Thursday as autumn-like conditions return. This low will signal a significant shift in the pattern as an Eastern US trough attempts to establish itself Friday into the weekend. The shortwave energy aiding in carving out this trough may develop a coastal storm that could brush the region with some wind and precipitation Friday night and Saturday before exiting, leaving behind mostly fair skies and seasonable temperatures Sunday.


Short-term - Issued 10/14 @7:25am


High and mid-level cloudiness continues to stream across the region this morning and may increase some this afternoon as a trough of low pressure approaches from the west. Merely a shadow of its former self, this trough won’t deliver much change in the sensible weather as rather mild conditions will continue to prevail over the region. Temperatures over the previous several days have averaged well above normal during the afternoons, upwards of 15 degrees in some cases, and this should be the case today as well. Expect high temperatures to reach into the 60’s to low 70’s across the interior with mid to upper 70’s along the coastal plain. Some urban locations of northeastern and south-central New Jersey, extreme southern New York and southeastern Pennsylvania may even break 80°F.

What’s left of the trough will wash out over coastal sections tonight. Clouds still hanging about will make for another mild night for mid-October, especially across eastern sections as lows only drop into the mid 50’s to low 60’s in the urban areas along the coast. Across the interior lows will drop into the mid 40’s to low 50’s with the lowest readings towards the west where clouds will disperse after midnight.

A narrow surface ridge axis moves across the Northeast on Wednesday, clearing out most of the leftover cloudiness and allowing for one last day on indian summer. Once again temperatures will average some 10-15 degrees above normal, despite slight cooling aloft as near full-sun will make up for the slight drop in temperatures, which will be quite similar to today’s readings. Clouds will be on the increase once again Wednesday night as low-pressure currently organizing over the Southern Plains takes a northeasterly track towards the Eastern Great Lakes. Light to moderate rain will move into western Pennsylvania and the Niagara Frontier after midnight as the remainder of the region stays dry through the overnight. Temperatures will be held 10-15 degrees above seasonable norms with the clouds overhead and a southwesterly breeze kicking up.


Mid-term - Issued 10/14 @7:25am


Aforementioned low pressure system moves through the Northeast on Thursday bringing the first significant rainfall in a week to the region. Highest rainfall totals appear to cut directly trough the center of the region with amounts ranging from a third to three-quarters of an inch. To the north and south of the track of this low rainfall amounts will be less, generally under a quarter inch in more widely scattered precipitation. Slightly unstable air in the warm sector out ahead of the low may sneak into southeastern Pennsylvania and central/southern New Jersey, which may allow for some thunder. Currently models show several hundred Joules of CAPE across this region but kinematics, almost a necessity for autumn thunderstorm events, aren’t too impressive as models have progged only ~35kt flow @500mb and around 20kts @850mb. Dynamics aren’t oriented favorably for thunderstorm development either, with the warm sector lying in the right exit region of a paltry (by autumn standards) 90-100kt upper jet. Clouds and precipitation should knock temperatures down closer to seasonable averages. Low pressure and associated precipitation moves offshore the New England coast Thursday night. Clearing skies will be left in its wake and much cooler temperatures compared to nights previous.

High pressure builds into the region on Friday with fair weather returning and temperatures more autumn-like, despite the abundant sunshine. 850mb 0°C isotherm dips down into central New York and New England as winds shift out of the northwest. Temperatures will range from the 40’s and 50’s across the interior with coastal locations perhaps reaching the low 60’s. High clouds will begin to filter in from the south Friday night as a coastal storm develops off the Southeast Coast in response to a vigorous shortwave diving down the backside of the developing Eastern US trough. Temperatures should drop below freezing for a good chunk of the interior with 40’s expected along the coast.


Long-term - Issued 10/14 @7:25am


Model consensus breaks down by the weekend as the potential coastal storm off the Southeast Coast makes an attempt to push northwards but will have trouble doing so with the presence of strong high pressure centered over the St.Lawrence Valley. Clouds should increase across southern sections as will the wind given the difference in pressure between the high along the international border and the low off the Carolina Coast. However, much of the region should escape precipitation during the day on Saturday as confluent flow should hold off any rainfall. The storm should slowly pull away on Sunday but just may brush eastern Long Island and Cape Cod with some showers that will attempt to rotate back towards the coast. Otherwise variable clouds will be found across the region as temperatures both Saturday and Sunday will average near normal.

Low pressure will move into the Canadian Maritimes early next week as a northern branch disturbance drops a strong cold front through the region. Temperatures should fall below normal and many locations that have yet to see a frost and/or freeze across the interior may have their growing season come to an end. A few higher elevation locales may even see their first snowflakes of the season.

___________________________________________________________


Radar: Northeast Region Loop

NE radar


___________________________________________________________

Local SST's

Northeast SST's

Updated: 10:15 AM GMT on October 15, 2008

Permalink

Indian Summer

By: sullivanweather, 1:43 AM GMT on October 11, 2008



Finally found the internet!!

Well, not yet, but soon!
On Monday the 13th I'll be getting Hughesnet (wish me luck as I've been told that satellite internet is horrible; almost on par with dial-up!) Unfortunately, my new place doesn't have cable (but Slime-Warner said they will install cable lines on our road for $11,000) nor DSL, so my choices are limited.

Tonight I'm writing from Kate's parents house. In order to hasten the time I spend monopolizing their computer I'll add a short update and hopefully everything will be ready for regular in-depth updates starting Monday.

I plan on commenting on the upcoming winter season in a blog before October closes out and I also found a jackpot of cache satellite images from the 2004/5 hurricane seasons on my PC during this downtime which I'll hopefully incorporate into a blog sometime in he near future. For those of us that follow the tropics 2004 and 2005 were definitely two memorable seasons that deserve a second look. I also thought it would be neat to have a blog with some satellite images of those storms. Gives a chance to those that don't have copies of satellite imagery from that year.

Current watches, warnings and advisories.


Eastern US current watches/warnings

------


Deep layer ridging will build over the Northeast over the next 2-3 days bringing a lovely spell of Indian Summer, with mainly sunny skies and above normal temperatures during the daylight hours and clear cool nights. Early next week a downstream cut-off low will develop over the Western Atlantic south of Newfoundland, forcing a backdoor cold front down into the region along its western flanks, cooling temperatures along the coast Tuesday. An early-season winter storm currently affecting the western states will shear out over the Northern Plains and send a weak cold front into the region by midweek bringing the first chance for precipitation since last week. The recent pattern (western trough/eastern ridge) finally breaks down by late next week as the jet stream becomes more zonal and storm systems become more progressive. Temperatures will also return to near normal readings for mid-October.

___________________________________________________________


Radar: Northeast Region Loop

NE radar


___________________________________________________________

Local SST's

Northeast SST's

Permalink

About sullivanweather

Thomas is an avid weather enthusiast, landscaper and organic gardener. This blog is dedicated to Northeast and tropical weather forecasting. Enjoy!

Local Weather

Clear
37 °F
Clear

Personal Weather Stations

Barryville, NY
Elevation: 1012 ft
Temperature: 35.5 °F
Dew Point: 29.0 °F
Humidity: 77%
Wind: Calm
Wind Gust: 0.0 mph
Updated: 12:35 AM EDT on April 20, 2014
Town of Lumberland
Glen Spey, NY
Elevation: 1326 ft
Temperature: 40.6 °F
Dew Point: 24.8 °F
Humidity: 53%
Wind: Calm
Wind Gust: 0.0 mph
Updated: 12:34 AM EDT on April 20, 2014

About Personal Weather Stations