Ph.D. Student - Earth System Science (UC Irvine), B.Sc. - Atmospheric Sciences (Cornell University)
By: Zachary Labe , 10:33 PM GMT on November 01, 2009
"Afternoon Thoughts" (Updated 11/1)
Good evening!!! So it is that time of year being November 1 is Sunday, to bring out the winter blog format for the general weekly discussion. Also be sure to check out my November outlook posted below. As usual significant storm systems, lake effect snow outbreaks, strong Alberta clippers/Manitoba Maulers/Saskatchewan Screamer, or polar air plunge will bring out a specially formatted blog for that occasion. Generally if you remember special blogs are the usual blogs issued during the winter unless the week looks relatively quiet, and therefore will allow for this formatted blog to be posted. I tried to accompany everyone's needs in terms of weather maps. If I am missing anyone's favorites, just drop a comment by. So our winter journey begins, hop aboard to "congo" train.
Well Sunday is the start of November, which always reminds me of one of the dullest, grayest months of the year. Stratiform rain events with temperatures in the 40s always seem to dominate the pattern, with chilly frosty nights on a brown countryside. It amazes me how brown things already are across the region as Blue Mountain is nearly completely brown except for some yellow oaks especially below 800ft. Many leaves have come down, and the colors of Autumn are quickly by the wayside. The fun holiday of Halloween is already over and Thanksgiving plans are being made. Recreational outdoor activities are just about over with Fall sports coming to a close excluding championships. Friday night football games now bring an extra chill to the air at night, and local wildlife begins to make final preparations for winter hibernation. I have noticed an increase in squirrel and deer activity the last week across south-central Pennsylvania. Now neighbors and local news media have reported bear sightings in my neighborhood just a few homes away; must have come out of the mountains. It seems the cloudy pattern has already set in with these last few days of October being under a marine layer with who knows when the last day of sunshine was. Acorns continue to fall through trees onto the forest flow in quite an abundance I must say this year. On a meteorological approach November starts the forecasting challenge months with model mayhem and all the fun that goes along with that. Precipitation type issues become a problem, especially towards the end of the month and looking at thermal layers becomes more important than ever. Skewt T charts become more important along with bufkit data to determine well 850s are below 0 with surface temperatures in the mid 30s, but yet it is raining because 1000-500mb thickness are above 540. This is also the time of year where elevation becomes critical with a general rule of thumb emerging for every 1000ft there is a 3-4degree temperature difference. Lake effect activity begins to heat up with CAPE, Omega, dendritic growth, ice crystal development, wind trajectories, etc becoming critical. O the joys of forecasting from now through March and early April. But for me this is my favorite time of year for forecasting; there is so much to be learned and gained everyday and the challenge makes it all the better. I will try to put my nose out, when it proves prudent for difficult forecasts whether my solution works out or not. The time changes also allow for models to come out an hour earlier, which is very beneficial on some busier nights of the week. El Nino years are some of the most model mayhem years there are during the winter, so let it begin. Are you ready for another forecasting season? Have a great day!!!
"Current Surface Plot"
(Courtesy of HPC)
(Courtesy of Wunderground)
(Courtesy of NOAA)
"Forecast Discussion"(Pennsylvania, Maryland, Delaware)(Updated 11/1)
So my previous setup had two sections with forecast discussions with one being for the three states and the other for the Lower Susquehanna Valley. It seemed that I kept repeating myself in both sections, so I decided for the winter format to have one discussion to talk about the forecasting techniques and discrepancies used in my official forecast, which is below. This discussion will allow me to express my thoughts along with an analytic approach to perhaps mention past data to support a forecast or mention about model discrepancies. Hopefully this format will suit to everyone’s liking and will not be just another restated section with the same details.
1028mb high pressure begins to nose in from the west allowing the easterly flow regime to push off the coast. Some of the overrunning precipitation along the slow moving cold front will impact far eastern zones in Delaware in early evening, but low stratus will push offshore for a chilly night. MOS GFS guidance suggests low in the low to mid 30s for areas in southern Pennsylvania and northern Maryland with lows in upper 20s for northern Pennsylvania and upper 30s for southern Delaware and Maryland. But with clear skies and falling dewpoints I would chop off about 2-4degrees off MOS guidance with lows at or below 32F for most areas north of northern Maryland. For central Maryland and southern Maryland including Delaware lows in the mid 30s are likely with frost formation. ECMWF guidance running a bit colder this week with H85s for a majority of the region around (-4)C-(-6)C especially after Tuesday. 1024mb high pressure generally looks in control for Monday across the northern Middle Atlantic with slightly below normal temperatures. 2m GFS/NAM combo temperatures look to be a good bet for Monday generally in the low to upper 50s ranging over the Pennsylvania, Maryland, and Delaware region. GFS seems to be running a bit too cold with highs verifying around 3F warmer than model printout. Sunshine will dominate the region with dry air through the vertical Skewt T profiles. Winds out of the 299degree trajectory will allow for some scattered cumulus to form over the higher elevations of western Maryland above 2000ft up through the Laurel Highlands and North Central Mountains of Pennsylvania. Thickening clouds Monday night with increasing mid level cirrus will allow for a milder night than Sunday night as GFS guidance suggests a general 40%-70% cloud cover over the region. But despite this, decoupling winds will allow for some radiational cooling conditions with near normal lows in the 30s and low 40s over the Northern Middle Atlantic. PWATs increase slightly on Tuesday up to .6inches as an advancing shortwave moves through the region reinforcing the cold air as 1000-500mb thickness fall at or below 540 according to the latest ECMWF runs. A 305degree wind trajectory will prevail Tuesday as H85 winds increase to 30knots allowing for a sharp northwest flow. This will keep cloud cover over the region with a strato-cumulus deck especially closer to the lakes. NAM QPF prints little to no precipitation over much of the region, but combined with a SREF compromise a few hundredths may be printed out especially with a lake influence. Vertical temperature profiles suggest thicknesses may support a few wet snowflakes towards Bradford especially Tuesday night. With a sharp northwest flow and mostly cloudy skies, temperatures will be below normal with GFS 2m temperatures around the upper 40s for areas north of the Mason-Dixon Line with low 40s for northern Pennsylvania. That may verify just a bit too cold. GFS and ECMWF really enhance the cold air for Wednesday as a 1024mb anticyclone moves over the Middle Atlantic cutting off the lake enhanced precipitation over the far northwest. GFS 2m temperatures suggest bitter cold highs for Wednesday and Thursday with temperatures below 50degrees for areas north of northern Maryland. This seems a bit too cold, but for now I am slightly leaning towards the colder guidance. NAM temperature profiles are a bit warmer, but H85 NAM temperatures have not been verifying well this month. Another weak ripple in the jet approaches the region towards Thursday and Friday with GFS QPF near .1inch for some areas especially over Pennsylvania. Vertical temperature profiles suggest H85s at or below -6C with 1000-500mb thicknesses near 535dm on average. But with the center of circulation for the Alberta clipper passing to the northwest, surface temperatures should warm into the 40s for many areas. But despite this any evaporational cooling aloft may pose a threat for some light snow showers over Pennsylvania especially towards Friday. I am not quite buying the ridiculous latest GFS and ECMWF guidance of highs not reaching 40degrees on Friday for even areas as far south as KMDT, but I am monitoring the potentially cold air. ECMWF has an amplifying low pressure in southern Canada and I am watching this scenario for maybe a light snow event especially towards the higher elevations of New England. GFS algorithms even favor a few inches of snow towards Bradford, although that has a cold bias. NWS looks to be running a bit too warm in this time period for forecast temperatures too. Lake effect snow potential also exists in this time period with a 320degree trajectory. The (-2)-(-3) deviation trough will slowly lift out of the region towards the weekend. So generally this week looks below normal temperature wise with possibly well below normal temperatures towards the end of the week with several chances at, at least snow flurry potential for northwestern Pennsylvania and western Maryland. Keep an eye on Friday.
(Courtesy of Penn State Meteo.)
"Current Water Vapor Loop"
(Courtesy of Penn State Meteo.)
"7-Day Zonal Forecast Outlooks"(Pennsylvania, Maryland, and Delaware)(Updated 10/31)
Monday- High pressure dominates the weather across the Northern Middle Atlantic with weak troughing in place over the region. A cool northwest flow will keep temperatures slightly below average and allow for scattered cumulus to form over the higher elevations from South Mountain in Pennsylvania through western Maryland up through the spine of the Appalachians and Alleghany Plateau in Pennsylvania. This will allow for temperature 4-6degrees below normal for highs. Morning frost is likely for many areas after a very cold night Sunday night with frosts and freezes likely from northern Maryland and northern Delaware on northward through all of Pennsylvania excluding the Philadelphia region. Patchy fog is also possible especially towards the Middle Susquehanna Valley up through Williamsport where air and water temperature inversions remain near 25F differences. Patchy VFR fog is also possible across other valleys especially in Pennsylvania. Fog and frost will quickly dissipate over the region with plentiful sunshine. Highs will range from the low 50s over elevations above 1800ft across northern Pennsylvania with mid 50s likely for a majority of the state with upper 50s towards Philadelphia and Lancaster. Upper 50s to low 60s are likely for much of Maryland with low 50s west of the Cumberland Gap and mid 60s for areas to south coastal Maryland. Across Delaware a uniform high range of 54-58 is likely statewide. Monday night will feature clear skies with increasing cirrus over the west keeping a hold on temperatures. Dewpoints will be low with calm winds allowing temperatures to fall in the 30s for most areas outside of the urban areas and coastal waterways towards the Delmarva. Lows in those warmer regions will be in the low to mid 40s. Widespread lowering alto stratus is likely for many areas along and west of the Blue Ridge by daybreak.
Tuesday- A weak shortwave will be advancing towards the region to reinforce the trough and aid in carving out a deep trough by the end of the week. Lowering alto-cirrus and alto-stratus is likely by daybreak with some patchy fog likely over the eastern Maryland and Delaware valleys courtesy of the cooler morning lows in the upper 30s. A cool, cloudy day is in store for much of the Appalachian region with more partly cloudy skies the farther east one goes. A weakening center of circulation will be moving of the region with very dry air associated with it. Despite this some precipitation is possible over western Pennsylvania and western Maryland courtesy of the lake effect flow with a northwest wind and orographic lift. Generally less than a tenth of an inch of rain will occur in these regions with generally patchy drizzle elsewhere over the Northern Middle Atlantic. Highs will be the warmest of the week with a weak southwest flow at the surface as the low tracks north of the region. Highs will range from the mid 40s near Bradford to the low to mid 60s near Washington DC. Most of the region will have dry conditions. Towards Tuesday night the northwest flow will be reinforced by the generally dry cold frontal passage allowing partly to mostly cloudy skies expected much of the night over the region with a northwest breeze. With falling temperatures aloft some wet snow flakes are possible towards northern Pennsylvania especially above 1700ft. Generally dry conditions are expected elsewhere. No snow accumulation will occur. Lows will be the warmest of the week as cloud cover and wind will prevent temperatures from really dropping off. Lows will range from the low to mid 30s over northern Pennsylvania and western Maryland, upper 30s over central and northeastern Pennsylvania, low 40s over northern Maryland, mid 40s over the rest of Maryland and Delaware.
Wednesday- High pressure moves back in control across the region weakening the northwest flow and any lake enhanced precipitation that forms. Any snow flurries over the far northwest will dissipate by 8am. Partly cloudy skies are likely over much of the region with clear skies east of the Blue Ridge Mountains courtesy of a downsloping wind. Temperatures will likely be several degrees below normal over the entire Northern Middle Atlantic with well below normal temperatures over the higher elevations. Highs in the upper 40s are likely for southern Pennsylvania, excluding Philadelphia with low 50s throughout all of Maryland and Delaware. Highs in the mid 40s are likely in the I-80 corridor with low 40s are across all of the northern tier border counties especially above elevations of 2000ft. Wednesday will likely be the coldest night of the season as high pressure remains in control with clear skies, calm winds, and dewpoints in the 20s. Low 20s are likely for northern Pennsylvania especially near Bradford and across Tioga, Potter, and McKean Counties. Lows in the mid 20s are likely from Johnstown to Altoona to State College to Wilkes-Barre with upper 20s likely for a majority of the southern portions of Pennsylvania with low 30s for Philadelphia. Upper 20s to mid 30s are likely for all of Maryland and Delaware with a few low to mid 20s over the Alleghany Plateau in western Maryland. Patchy deep river valley fog may also form overnight courtesy of the high water to air temperature contrast overnight. Most areas excluding the inner cities will likely have a hard freeze.
Thursday- Widespread heavy frost is likely over the entire northern Middle Atlantic towards Thursday morning as high pressure remains in control but slowly departs to the east of the region. Any patchy fog with visibilities below 1mile will likely burn off by 8am or 9am. Sunshine will generally rule conditions for the first half of the day before high and mid level cirrus work their way into western areas ahead of a weak shortwave that will slowly be strengthening and amplifying and will pose an interesting solution towards Friday. In any case Thursday will continue the theme of well below normal temperatures with highs around 10degrees below normal. Highs will range from the upper 30s near Bradford to mid 40s over the central third of Pennsylvania running west to east to upper 40s over the southern portions of the state. Upper 40s are likely for northern Maryland with elevations above 2000ft seeing readings in the low to mid 40s. Lower 50s are likely for Delaware and the rest of Maryland. Thursday night will bring in increase in clouds especially for areas to the west ahead of an advancing shortwave mentioned above. Some light precipitation may occur later in the evening towards western Maryland, but especially over northwestern Pennsylvania. These areas may see rain and snow showers as temperature profiles favor very cold air aloft. Little to no snow accumulation is likely even above 2500ft. Lows are likely in the 30s for all of Pennsylvania and western Maryland with low 40s for the rest of Maryland and Delaware.
Friday- Friday poses an interesting solution as an amplifying shortwave perhaps transfers some energy offshore allowing for some light precipitation under the very cold atmosphere aloft and at the boundary layer. Widespread clouds are likely over the entire northern Middle Atlantic with ongoing snow showers likely over northern Pennsylvania towards daybreak. A deep trough will carve over the eastern United States with unseasonable temperatures. Diurnal heating of the atmosphere may allow scattered showers to develop, especially over Pennsylvania during much of the day where temperatures combined with evaporational cooling may result in rain and snow showers and perhaps all snow showers over areas north of I-80 or elevations above 1300ft. Accumulation is not likely although the situation is being watched especially for areas towards New England. Despite any precipitation scenario highs will be near 10-15degrees below normal with highs in the low 30s for northern Pennsylvania, mid 30s for central Pennsylvania, and upper 30s to low 40s for southern Pennsylvania. Across Maryland and Delaware mid 40s are likely. Friday night will feature more rain/snow showers over the region especially towards areas north of the Pennsylvania turnpike. Again any accumulation is in question, but I would watch the lake effect snow belts for some light snow accumulation possible. Lows likely in the 20s to 30s are will occur over the entire Northern Middle Atlantic with mostly cloudy skies under a northwest flow.
"Current River Ice Reports and Ski Conditions" (Updated 11/1)
Well obviously the ski resorts are not open on the east coast, and there is zero ice on any waterways so this discussion is basically worthless until about mid to late November. But this discussion will still talk about water temperatures and opening dates for ski resorts. Water temperatures in Lake Erie have been steadily dropping through October now into the low 50s. Some of the more shallow channels towards the Erie shore through Cleveland are reporting water temperatures as low as 51degrees. Up towards Buffalo temperatures are slightly warmer towards the lower mid 50s near 54degrees. These water temperatures are cold enough for hypothermia to set in if someone enters or falls into these waters. Cold water temperatures provide a shock to the nervous system rapidly increasing heart rate and providing a shut down to the body after an extended period of time. Movements are slower and inhibitions are weakened. Please act responsibly when near waterways this time of year especially as we progress through the month of November. Below are a few listed planned opening dates for Northern Middle Atlantic Ski resorts. These dates are subject to change. Based on the winter forecast, it looks like a great ski season is ahead for the entire east coast with plentiful amounts of snow especially in comparison to the last few winters. I have been looking at some of the latest data and while I think patterns will be transient with sometimes the trough to our west, I do not see chances at extended warmer than normal periods especially in comparison to the last few winters. Many ski resorts especially in the snow belts will likely be making snow by the middle to end of November depending on conditions. See my November outlook below for more information.
Blue Mountain Ski Area... December 1
Camelback Ski Area... December 5
Tanglwood Ski Area... December 18
-Link to official reports page from NWS...Link.
-Link to local ski resort snow conditions...Link.
"Current Northeast Snow Depth and Northeast Wind chills"
(Courtesy of Wunderground)
"Lake Effect Snow Conditions" (Updated 11/1)
As for the beginning of November, it is understandable that there are few lake effect snow threats this week and for the next few weeks at that. Anyways there is one chance this week for a few lake enhanced rain/snow showers for northern Pennsylvania. Tuesday night a shortwave will rotate along the trough axis and move through the Great Lakes up through Quebec and Ontario. It will allow the flow to turn to a 269degree trajectory. GFS bufkit data suggests H85s dropping to around -5C with boundary layer temperatures remaining marginal in the lower 30s Tuesday night. But with a weak trigger and a meager flow with winds near 10-15mph, there will not be much lift. Still a few lake effect snow showers are possible towards Bradford Tuesday night. Winds will shift to a 337degree trajectory towards early Wednesday morning allowing the moisture to cut off from the lakes as the low turns more northerly and high pressure moves in with a -2 deviation trough. No accumulation is expected for northern Pennsylvania. Elsewhere a typical northwest flow will occur Tuesday through Wednesday with a chance at a few rain showers as a weak reinforcing cold front moves through with scattered cumulus. So far there have not been any lake effect snow outbreaks for the Northeast. A few lake effect rain bands have occurred especially towards New York State where several inches of rain fell near Oswego through the Tug Hill Plateau accompanied by thunder and wind. Lake effect snow season usually begins to kick in towards the end of November with usually the first outbreak of lake effect snow during the month of November even in the warmer of winters. El Nino winters tend to favor some of the lake effect snow belts as the sharp temperature contrasts allow for steep lapse rates aiding in the development of stronger bands. So I guess we shall see soon enough...
"Current Lake Erie Wind Direction and Speed"
(Courtesy of NOAA)
"Current Lake Erie Water Temperature"
(Courtesy of NOAA)
"Long Term Outlook" (Updated 11/1)
I am a little bit hesitant towards the long term forecast as guidance and teleconnections have been switching solutions each day. But there is beginning to appear that there may be sufficient evidence for the coldest air of the young season to enter onto the east coast around the 11th of the month, or second week of November. Latest GFS predictions indicate very cold and unseasonable air with a negative EPO ridge forming in the west. Meanwhile the ECMWF is beginning to latch on to this scenario also indicating a steep trough forming over the east coast with slight hints at a weakly positive PNA and a weakly negative west based NAO forming in this time period. Arctic air has really been building across the north with cold air into Alaska also. This air may get dislodged around this time period headed towards the continental United States. Eurasia snow cover after having a severely and worrisome negative snow cover anomaly in the beginning of October, has made a remarkable comeback with nearly an above normal snow cover anomaly currently. This is great for signs down the road as far as building cold air masses over the polar regions. Arctic sea ice levels are also beginning to increase after some very warm southwesterlies in this region caused well above normal temperatures earlier in October. All this evidence points to a cold surge heading towards the United States around this time period. As far as where the location of the coldest weather will be remains uncertain, but latest guidance is certainly suggesting that it is possible for the east coast to be under the center of the trough axis. Latest ECMWF weeklies released a few days ago indicated slightly below normal temperatures across the east coast in this time period. As far as closer to medium term range the weekend of the 7th to 8th coming up is looking pretty quiet for now with near normal temperatures and at this point dry conditions, but looking at our track record I guess we can expect that to change.
"Current NAO and PNA Predictions"
(Courtesy of NOAA)
"Monthly Outlook" (November)
Well, how quick time flies by as now it is time for me to express the November Outlook. October went by pretty according to forecast with most climate reporting stations in my forecast (-1)-(-2)departure zone for areas excluding Philadelphia on southward which saw near normal temperatures. Many areas had their coldest October on record in the running around midmonth as a strong nor'easter brought snow to north central Pennsylvania with very cold temperatures, but later in the month temperatures warmed up with a sudden swing in the pattern to bring very mild temperatures for the last week of the month. Precipitation though was a bit more than forecast, with forecast calling for normal precipitation, but it turned out many areas are nearly 1-2inches above for October. But the change from the dry period to the active period was nailed by the original forecast, which called for the switch around midmonth which was accompanied by the series of nor'easters. All in all October's forecast was very successful. Anyways onto the November forecast. This was a difficult forecast for me as a lot of teleconnections and guidance show conflicting equations for a final solution. Teleconnections appear to support a near seasonal pattern for the first half of the month, before guidance starts to diverge in solutions. Latest ECMWF weeklies support a switch to a colder regime around the 10-15th of the month; this is also backed up by some of the ridiculous arctic runs of the GFS. The October 31, 12UTC ECMWF model suggests towards the 11th of November a return of the Aleutian Low with a weakly negative NAO forming, negative EPO, and a weakly positive PNA. This all suggests a possible pattern change to the trough axis surging eastward towards the east coast. Meanwhile Nino region 3.4 SST anomalies continue to rise favoring the moderate El Nino, which goes according to forecast. So all of this leaves a difficult forecast…
Temperature- It appears we will start the month with near normal to slightly below normal temperatures for the first week as we manage a weak trough in control with a series of high pressures. This will result in near normal highs, but well below normal low temperatures with ideal radiational cooling. Most locations will drop below freezing several times for this first week of the month. Towards the second week of the month and third week of the month is where model guidance is suggesting a negative AO, which will allow cold Canadian air to enter the continental United States. According to guidance this could be over the east coast with possible well below normal period. But as in El Nino regimes, patterns are transient even during the height of the winter so I do not think a trough dominates the flow of the east coast the entire month. There should be periods of above normal days between troughs entering the Midwest parading on eastward. Not exactly set in a forecast for Thanksgiving week, last week in the month, but the ECMWF weeklies are predicting temperatures to be below normal. Therefore my temperature forecast is going to be as followed... A general (-1)-(-3) departure for monthly anomalies for much of Pennsylvania and western Maryland, excluding Philadelphia. Towards the rest of Maryland through extreme southeastern Pennsylvania and all of Delaware I am going with a (+.5)-(-.5) temperature anomaly for the month. I think a weakening southeast ridge along with easterly flow for the first week will prevent ideal radiational cooling therefore limiting the below normal temperature extent in this region.
Precipitation- Precipitation proves difficult as usual because other than existing patterns, there is not too much information to base a forecast off of. I am going to go with a near normal precipitation month, but there is the possibility that the month could be dry. With nearly the last 6 months being above normal precipitation months, I will stick with a continued semi wet pattern. The first week of the month looks dry with perhaps a stormier pattern towards the middle and end of the month. If the center of the trough axis remains near the east coast, then likely the pattern will by drier. So a good rule of thumb for one to follow this month is a colder month will likely be drier and a warmer month will likely be wetter. Troughs situated to our west allow for warmer temperatures with weak ridging, but also active storms moving up through the Ohio Valley. As for snowfall, that forecast is extremely difficult but I would not be surprised if most all areas see their first flurries this month in the entire Middle Atlantic with a few periods of lake effect snow accumulation especially if the GFS cold outbreak pans out. As for synoptic snows, that remains to be seen.
"Temperature and Precipitation Outlooks from Climate Prediction Center for next 30 days"
(Courtesy of NOAA)
-Winter Outlook 2009-2010...Link
"Here northeast of Harrisburg 2009-2010 winter statistics"
Current Snow Cover- 0inches
Monthly Total- 0inches
Seasonal Total- 0inches
Winter Weather Advisories- 0
Winter Storm Warnings- 0
Ice Storm Warnings- 0
Blizzard Warnings- 0
Freezing Rain Advisories- 0
Winter Storm Watches- 0
Lowest High Temperature- 41degrees
Lowest Low Temperature- 23.5degrees
Wind Chill Advisories- 0
Wind Chill Warnings- 0
(Snow Storms Stats)
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.