Ph.D. Student - Earth System Science (UC Irvine), B.Sc. - Atmospheric Sciences (Cornell University)
By: Zachary Labe , 10:51 PM GMT on December 26, 2008
"Afternoon Thoughts" (Updated 12/26)
Good Friday evening!!! I want to first start off and hope that everyone had a wonderful Christmas! It is amazing that Christmas is already over, wow what a rush. Now onto New Years before the long, cold, and boring months of January, February, and March. This blog covers the period of weather from Friday the 27th to Thursday the 1st. Then towards the weekend a potential winter storm makes it's mark towards the Northeast. During early next week around the 30th or 31st I will likely issue my January Outlook with also my December verification.
So now we enter the new year. 2008 has come and gone with global impacts of a great variety. It is time for once again those New Year's resolutions, that we all know are never followed through, hehe. But in all honesty as many of us look forward to the new year, others sit depressingly looking at what horrible could go wrong with the new year. Truthfully the new year does mark a new you. It is a new beginning full of new opportunities. As the countdown at Time Square begins, let that mark the beginning of a fantastic tomorrow! Weatherwise, there are a many of things to look forward to. More thunderstorms, blinding snowstorms, and flooding rains are likely eyeing up our region as they always do. After coming off of what really was a quiet summer in terms of severe weather, it seems that once again the threat is there. As a whole Harrisburg is really not known for it's severe weather. While events occur such as the Flood of 72, Blizzard of 96, Tornado Outbreak of 04, and Hurricane Isabel of 02, but still these events are found far between each other by nearly every five years. Many parts of the country deal with blizzards, tornadoes, and hurricane threats every single year and what seems to be every single month during some seasons. But the one remarkable thing I can say about Pennsylvania weather is the variety and seasonability that we are so lucky to experience. You can find every type of weather in the state nearly every year in every season. So what will the weather bring our area for this coming year? No answer can be given, but I know for sure that I will be here to track it for another year and I look forward to everyone else here along with me tracking these systems. Have a wonderful New Years!!!
"Current Surface Plot"
(Courtesy of HPC)
(Courtesy of Wunderground)
(Courtesy of NOAA)
"Forecast Discussion" (Updated 12/26)
High pressure located over northern Maine and the Canadian Maritimes will be departing to the east giving way to a strong southwesterly flow with rising heights. Warm air floods in across the Northeast by late Friday night with any shallow cold air being displaced now farther to the north. QPF initially will be very light generally a few hundredths of an inch. Then by Saturday for the first time in quite a while H85s will rise above 10C statewide across Pennsylvania as southwesterly flow takes over with winds occasionally breezy on the ridgetops in the Laurel Highlands. 2m surface temperatures look to rise near 60degrees across southern Pennsylvania with 50s elsewhere. Snow pack will greatly melt. Developing low pressure in Midwest will head up through the Great Lakes as a 996mb low and bring a cold front eastward across the Ohio Valley towards Tuesday. Flow generally just brings marginally light precipitation for much of Saturday with QPF below .1inches for the most part. Cold front comes crashing through for Sunday with a cold front generally drying up as it heads eastward. H85s will dive from 10C to about 0C in about a 12hour period. Other than that front generally has weak dynamics with little QPF up to .25inches as a max. 500mb jet develops a more zonal flow to start the next week with a Pacific orientation airmass keeping temperatures around normal values. Arctic air will be hard to find anywhere across the CONUS. A ripple in the northern jet drops south out of Canada with maximum vortex lifting across New York State. Dynamics are lacking so shortwave will only generally bring reinforcing cooler air with H85s dropping to -10C across parts of northern Pennsylvania. Another disturbance drops down from Canada towards Wednesday with a bit better dynamics and a colder origin of air. Light warm air advection snows may break out across the State, but with QPF below .1inch, there will be little to no snow accumulation. Colder airmass moves in with H85s near -10C statewide. High pressure builds over region for Thursday and Friday with below normal temperatures setting the stage for a potential weekend storm.
(Courtesy of Penn State Meteo.)
"Current Water Vapor Loop"
(Courtesy of Penn State Meteo.)
"Weekly Forecasts" (Updated 12/26)
Saturday- Statewide it appears Saturday will be a dreary day with overcast skies and occasional drizzle. But I can report that warm temperatures will be found across the region under a strong southwesterly flow. On occasion breezy conditions with gusts up to 25mph may occur on the southern facing ridgetops. Some light rain will occur at times throughout the day with a few areas of freezing drizzle across the higher elevations. Precipitation amounts though will generally be under a tenth of an inch and temperatures will be above freezing by early morning. Highs will be very mild approaching some records in a few areas with highs in the 60s across southern Pennsylvania south of the turnpike, highs in the 50s should be expected elsewhere. Saturday night it appears drizzle and fog will be found statewide with locally dense fog across the areas with remaining snow cover. Rainfall amounts will be less than a few hundredths of an inch. Lows Saturday night will be extremely mild and near 20-25degrees above normal with them in the low 50s across southern Pennsylvania and 40s elsewhere.
Sunday- The cold front will be approaching from the west in the Ohio Valley sparking some rain showers statewide. High temperatures will once again be well above normal with them similar to Saturday highs likely in the 60s in the south and upper 50s elsewhere. I would also watch for a few areas of thunder to develop as some unstable air works into western areas and all southern areas. Rainfall amounts will generally be up to .25inches with lesser amounts towards eastern Pennsylvania as the cold front dries up. Sunday night the front will pass through the rest of the state with rain showers coming to an end. A few snow showers may linger up in northwestern Pennsylvania but little to no accumulation is expected. Lows will fall steadily through the night back to seasonal lows in the mid 20s across the northwest to low 30s across the far southeast. Some gusty winds will be found in the early evening behind the cold front gusting up to 40mph at times, but overall impacts should be below advisory criteria.
Monday- High pressure remains parked over region with sunshine prevailing statewide. A few snow showers in the morning are possible, though, across the Erie Plateau with snow accumulations up to a half an inch possible. Temperatures will be much cooler than they were Sunday, but still above normal as to seasonal values. Highs will be in the upper 40s across southern areas with low 40s across northern areas. Monday night will feature clear skies and calm winds giving way to radiational cooling. Still with dewpoints relatively high, I find it hard to see temperatures getting very cold. Lows will drop into the low to mid 20s across northern valleys with upper 20s found elsewhere.
Tuesday- A dry disturbance drops down from Canada on Tuesday giving way to sunny skies to start the day followed by afternoon clouds. Little in the way of precipitation is expected other than a few flurries across the northwest. Highs will be cooler back down towards more seasonable readings with highs in the low to mid 30s across the north and low 40s across the south. Winds will turn out of the northwest bringing in colder air for Tuesday evening. Tuesday night will feature cloudy skies across the state under a northwest flow. Lows will be back to normal lows will lows in the teens across the northern mountains to mid 20s across southern areas.
Wednesday- An Alberta Clipper along with a cold front works its way down into the region with the center staying to our north in New York State. None the less some light snows will break out across the state with even light rain mixing in for southern areas. Generally snow accumulations will be less than one inch and rain totals will only wet the ground and be reported as a trace. Cloudy skies will prevail under a stratus deck. Flow will turn more northwesterly as weak cold front passes through with another slightly colder airmass. A few lake effect snow showers look to form across northwestern areas with accumulations up to one inch in the snowbelts. Wednesday night high pressure moves into control ending any residual snow showers giving way to clear skies with light northwesterly winds preventing temperatures from dropping to low. Still low temperatures will drop in the teens across the north to mid 20s across the south.
Thurday- High pressure remains in control statewide with sunshine prevailing. Temperatures will average a degree or two below normal with highs in the upper 20s across the north to upper 30s across southern areas. Winds will be light out of the west. Thursday night clear skies with light winds and low dewpoints will give way to great radiational cooling conditions. Lows will drop into the low to mid teens across the north with upper teens to low 20s across the south. A few clouds may approach the region from the south ahead of the next storm system.
"Current River Ice Reports and Ski Conditions" (Updated 12/26)
Interestingly enough the other day the Susquehanna River had moderate ice traveling down it with it in the form of sheet ice. Climatology suggests this is a relative rarity for December standards for southern branches of the river to have moderate icing. There was also a river-water rescue the other day during all of the ice jams as a boats motor was reported stalled out near Rockville. Fortunately everything turned out ok. But this is a constant reminder that waterways in the winter time are very dangerous. With the coming warm spell, any waterway with ice still on it will melt so please take caution around the melting ice even across northern areas. Ice fishing does not look possible this coming week. Colder weather does move in for the end of next week. As for ski reports, ski conditions will develop to the poor level for this weekend as rain and very mild temperatures overtake the region. There will be significant snow melt across all ski resorts. Towards the start of next week conditions will improve and snow making will be allowed to resume. Natural snow looks to be hard to come by this week with only about one inch of natural snow found up near Erie and Bradford, maybe a dusting across the Laurel Highlands. Chances of snow do increase though towards next weekend. Looking at the pattern down the road it does seem relatively stormy so period of snow will be possible in early January. Overall ski conditions will remain from poor to slow throughout the entire week. Temperatures will only fall below freezing during the night time low temperatures. Thursday will be the coldest day of this term.
-Link to official reports page from NWS...Link.
-Link to local ski resort snow conditions...Link.
"Current Northeast Snow Depth and Northeast Windchills"
(Courtesy of Wunderground)
"Lake Effect Snow Conditions" (Updated 12/26)
Little to no chances of lake effect snow this week as flow generally remains more zonal and westerly. Water temperatures generally remain in the 30s across Lake Erie with some near 32degree readings towards Toledo, Ohio in the more shallow part of the lake. Ice reports remain to be very few across the Lake Erie region. So it seems that we still have a while to go before the lake effect machine cuts off for Pennsylvania. Best chances of any lake effect precipitation will be late Sunday into early Monday after cold front moves through region. But airmass in generally Pacific with H85s only near -5C, which is not cold for this time of year nor unstable enough for widespread snow bands. Winds will also be light near the 270 trajectory out of the due west. But none the less a few scattered snow showers may occur in Erie County with a coating to one inch in a few isolated spots, nothing more than a mere nuisance for that region. Then high pressure moves in for midweek before a disturbance moves down for Tuesday into Wednesday in the form of a clipper. Flow turns a bit west-northwest along with colder air near -10C 850s. But high pressure quickly moves in region by Wednesday night. Still a few cells of lake effect snow showers may form in some northwestern snowbelts dropping up to 1inch of snow maybe 1-3inches on the Erie County Plateau. Towards weekend high pressure remains in control. So all in all very few lake effect snow concerns to worry ourselves with as northern jet stream remains fairly stable unlike the past week or two. Much of the ice along with the lake shores and freezing mist will generally melt in the next few days as a two-day mild spell moves over the region. Cold air will be hard to come by, but that goes by your definition of cold. Highs will be in the 30s across the snowbelts, but to me that is not cold for this time of year for what it could be with highs in the teens and twenties. Seasonable seems to rule the roost the week.
"Current Lake Erie Wind Direction and Speed"
(Courtesy of NOAA)
"Current Lake Erie Water Temperature"
(Courtesy of NOAA)
"Long Term Outlook" (Updated 12/26)
Very difficult long term section for forecasting as model variables have been difficult in showing trends. January is looking highly volatile in terms of temperature trends. It does appear a cold regime will make its way back towards the eastern CONUS, but for how long. The NAO is showing signs of heading sharply negative along with some favorable Greenland Blocking. GFS is been highly advertising building heights over Greenland with a ridge, but during the past few model runs it has been backing off with its solution. The Pacific remains the volatile region which could offset the primed Atlantic. PNA index is in question whether it will rise positive, but GFS ensembles insist it will towards early to mid January. MJO phase also appears to be shifting during the next 20 days to a more favorable trough phase for the east coast of either phases 5 or 6. The AO index is also headed highly negative during the early January time period. Now what has me worried about the pattern is the considerable cooling of the sea surface temperatures in the Central Pacific putting us back into a La Nina state. Now I was forecasting a return of a weak La Nina status, but it does seem the cooling is a bit more than first anticipated by many including the Climate Prediction Center. The implications of this Nina development may really cause some issues down the road with southeast ridge development and western troughs. Still though, those impacts remain to be seen. Now back to the closer long term. A storm is progged across somewhere east of the Mississippi towards the weekend. Greenland blocking and a negative NAO look to remain in place along with a high over southern Canada. Typically that would mean east coast snowstorm, but latest models runs are increasingly showing an inland cutter. Still though I think it is just part of the wild swings in the models especially this far out. A miller B solution looks very possible with the primary weakening near the Ohio River giving way to secondary developing over northern North Carolina and heading up coast delivering a nice ol' winter storm, but confidence remains slim with any solution at this point. EURO is showing wild shifts with lows by near 100mi for each run. GFS had been consistently showing a coastal low solution, but now the last two runs are towards inland runner. It seems to me that a more coastal solution makes more sense as long as the Pacific cooperates. In any case a major winter will likely impact parts of the Northeast for next week. I will have model run updates throughout the coming week.
"Current NAO and PNA Predictions"
(Courtesy of NOAA)
"Monthly Outlook" (December)
So here it is the first month of the meteorological winter, and quite hard to believe at that. It feels like we were just watching severe thunderstorms role across the heartland and hurricanes roar across the Gulf of Mexico. But now it is our season for extreme weather; winter storms. Looking back at my November Outlook I called for normal to below normal temperatures with normal precipitation. That is very close to what actually happened and with the temperature department I nailed it spot on. Temperatures for the first half of the month were well above normal and by the second week temperatures plummeted to the coldest temperatures we had seen in November in quite a long time. Temperatures average below normal by a few degrees, but it could have been an even bigger anomaly if we had not seen that very warm outbreak in the beginning of the month. Snowfall I called for normal snowfall to above normal snowfall, and many areas across Pennsylvania are running 150% above normal in the snowfall department. The only area really lacking snowfall is in the Lehigh Valley where they have only seen a few coatings, even the Philadelphia snow season is starting off with a bang. Some areas in the snow belts near Erie have seen some of the snowiest weather in November in decades. Precipitation as a whole though was slightly below normal to normal in most areas. It seems we have been caught in a somewhat drier pattern lately in comparison to other years, still though we are far from a drought. So for December here is what I see…
Temperature- For quite a few months as far back as August, December was looking to be an extremely cold weather in comparison to normal. Now as we approach December, very little has changed in that regard. I am forecasting below normal temperatures across the entire state. Now the anomaly will not be extreme, but it will be enough for a couple of degrees below normal as a whole. I am expecting very cold weather for first week or two of December, before a more rollercoaster type pattern with cold followed by warmth. Then for the end of the month I think the coldest air moves over the Northeast with the coldest weather possibly of the whole winter. There are teleconnective signs of a decent negative NAO that would favor deep troughs over the east coast. But there are a few discrepancies with the models with some favoring a western Atlantic ridge and warm air up the east coast. But I still think the models think we are in a stronger La Nina pattern than we actually are. Just recently the climate CFS model which was forecasting a strong La Nina again, has now backed up to a weak La Nina which is more reasonable. I must also mention that now the CFS shows below normal temperatures across Pennsylvania for every meteorological winter month. All in all I think December will favor below normal temperatures with even some more favorable blocking scenarios towards mid to late month.
Precipitation- Lately we seem to have been in a drier spell, so I find it hard to forecast above normal precipitation. So my forecast calls for normal precipitation with above normal snowfall. Looking at all of the global models, the ECMWF, GGEM, and GFS they all forecast a much stormier weather pattern starting the second week in December and lasting for quite a while. The northern jet seems to become the focal point of all the weather with storms even coming into the northern US Pacific coast and traveling transient across the nation and out to sea in the Middle Atlantic. At times there may be phasing between the northern and southern jet, which could lead to some strong winter storms across the central and eastern US. I also believe the pattern favors many Alberta clippers in which some of them could even be Saskatchewan screamers. Lake effect machine may end towards later in the month as Lake Erie may freeze over this winter, especially with how the pattern is looking. Warm air advection snows are also possible.
"Temperature and Precipitation Outlooks from Climate Prediction Center for next 30 days"
(Courtesy of NOAA)
-Winter 2008-2009 forecast... Link.
-Winter 2008-2009 forecast update... Link.
"Here northeast of Harrisburg 2008-2009 winter statistics"
Current Snow Cover- 0.00inches
Monthly Total- 4.35inches
Seasonal Total- 10.45inches
Winter Weather Advisories- 5
Winter Storm Warnings- 0
Heavy Snow Warnings- 0
Blizzard Warnings- 0
Snow Advisories- 0
Winter Storm Watches- 1
Lowest High Temperature- 23
Lowest Low Temperature- 10
Wind Chill Advisories- 0
Wind Chill Warnings- 0
(Snow Storms Stats)
First Snow - October 29 - Trace
First Snow on Ground - November 18 - Coating
Lake Effect Snow - November 21/22 - 6.00inches
Synoptic Snow - December 16 - 3.5inches
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Light Thunderstorm Rain Mist