Pennsylvania severe weather...
"Afternoon Thoughts" (Updated 2/1)
This blog does not yet contain information on the coastal storm so the weekly forecast and discussion is only valid for Sunday. But by Sunday afternoon I will update on post the full discussion and forecasts for each day for the rest of the week.
Good evening all!!! There has been quite a bit of talk about the state of meteorology and forecasts. Has forecast accuracy really increased in the last 10 years or has it declined? The age of technology and advancement of meteorology proves that we should be advancing. New Doppler radar, satellites, and computer models are supposed to be making the 3-day forecast become as accurate as the 1-day forecast and the 5-day forecast as accurate as the 3-day forecast and so on. But is this really the case? I mean look at our computer models. For predicting the 1993 superstorm all there really was, was the ETA model. And then along came the NGM. There were other models too. Now we have a plethora of computer models. Forecasting use to just consist of analyzing surface maps, patterns, and trends. Since then the real forecasting of weather seems to have diverted away from the old habits. But I firmly believe this is not the correct road to chose. When choosing to make a forecast you come to a two road path; either take the short road and take the computer models verbatim, or take the hilly road and look at overall pattern schemes to make forecasts. The later always seems to be more accurate. But that is not to say that forecasting without computer models is a solid accuracy. In fact during a test trial at the HPC, two meteorologists were chosen with one doing a QPF forecast looking at computer models while another meteorologist analyzed surface patterns. The computer model QPF forecast in the end proved to be more accurate. A balance of these two roads makes up the equation to an accurate forecast. In reality, the science of meteorology is relatively young and based off of complicated mathematical equations and a basis of many sciences such as Physics. Model verification will increase as continuously new satellites will take data from a global perspective and add them to the existing computer models. There are still many "white noise" locations across the globe where data is relatively limited and this results in highly volatile solutions capable of many scenarios in the long to medium term. Absolute forecasts are non-existent in every storm. We still do not have a great idea of how the atmosphere works and how weather in Asia correlates to weather patterns in North America. But we have come a long way from the magnetic local news weather boards of previous decades. Forecasts with the highest accuracy rating are those of a combination of old and new habits. And as new weather balloon data and ROAB data is launched, the practice of weather forecasts will improve. Overall analyzing patterns and hand drawing surface maps is just as accurate as looking at computer model simulations. The field of meteorology is a growing and continuously complex science that will mature greatly in the next 10 years. All we can do is take our best guess at what the weather will be tomorrow. But yes all it is, is an educated guess. We cannot quite prediction the future, but we sure can try. Looking towards the future we can only expect more "waking up to 10inches of partly cloudy," but we can hope those occurrences are far and in between.
"Current Surface Plot"
(Courtesy of HPC)
(Courtesy of Wunderground)
(Courtesy of NOAA)
"Forecast Discussion" (Updated 2/1)
A retreating trough gives way to a southwesterly flow for Sunday bringing in some mild air. A clipper system will be headed across the Northern Great Lakes and deepening to nearly 990mb which will help intensify the warm air advection. H85s will rise slightly above 0C across the Mason-Dixon line, but generally 850s will be near 0C statewide. A few snow showers cannot be ruled out across the northwestern part of the state as some .05 QPF is generated by the GFS and NAM. 2m temperatures will rise to nearly 5-7C across southern areas under a breezy southwesterly wind. Looking at the H5 chart a deepening trough will be dropping out of the Great Lakes towards Monday along with the passing of a cold front.
(Courtesy of Penn State Meteo.)
"Current Water Vapor Loop"
(Courtesy of Penn State Meteo.)
"Weekly Forecasts" (Updated 2/1)
Sunday- An approaching cold front will draw in southwesterly winds bringing in more mild air. Breezy conditions will persist throughout the day with gusts up to nearly 30mph on the southern facing ridgetops. Temperatures will rise into the 40s and possibly 50s. Snow cover will try to limit the warmth, but I think low 40s are likely across northern Pennsylvania with mid 40s in central Pennsylvania, and upper 40s for southern Pennsylvania. Areas near Philadelphia should rise to 50degrees or slightly above. Skies will feature altocumulus with some rain showers across the Laurel Highlands and snow showers across the Northwestern Mountains. Rain amounts will generally be near a trace with snow accumulations generally a coating to one half an inch. Downsloping conditions will cause no precipitation for east central and eastern Pennsylvania. Sunday night the cold front will move across the region bring a shift in the winds to the northwest. Lows will generally be in the low 20s in the mountains to upper 20s across the south under mostly cloudy skies. The front should stall across western New Jersey. A disturbance will ride up along the front bringing snow showers into southwestern Pennsylvania later Sunday night. Snow accumulations will be up to 1inch.
"Current River Ice Reports and Ski Conditions" (Updated 2/1)
Finally we got our cold and relatively snowy January that many people had been asking about for years. All waterways across the entire state of Pennsylvania have at least a little ice on them with most of them being frozen over. Latest ice reports from the Susquehanna area that most of the river is completely frozen over with 10% free flowing water near the Harrisburg river reporting station. Ice consists of frazil pans with snow cover. Up across the northern sections of the Susquehanna River there are reports of 100% ice/snow coverage near Lewisburg. Up towards Williamsport the east channel remains without ice, but the west channel is completely frozen over. Across the Juniata river basin near Clarks Bridge they are reporting complete ice cover with no free flowing water. Towards the Delaware River ice coverage is becoming thicker over time especially towards the Delaware Water Gap. Up across north central Pennsylvania near the Pennsylvania Grand Canyon Pine Creek is being reported as completely snow/ice covered with only free flowing water near the ripple locations. Across western Pennsylvania the triple river connector near Pittsburgh is being reported as ice covered. Across local lakes ice thickness is generally being reported with a 6-8inch thickness across the northern mountains with ice fishing having perfect conditions. Across southern Pennsylvania ice thickness in not thick enough on large lakes for most areas. Across the Lake Erie basin the lake is nearly completely frozen over with ice fishing being reported as quite popular. Overall it appears the winter time sports of ice fishing and ice skating look to have wonderful conditions continuing through next week as temperatures will only rise above freezing for one or two days on Sunday and Monday. Temperatures then drop below normal for the rest of the week. It still is very unsafe to walk across any frozen rivers as the ice is quite misleading and especially now with snow covering the ice hiding its actual thickness. Waterway ice conditions are being reported as the best in years!
Ski conditions are being reported as the best in years with many ski resorts reporting bases up to 70inches of snow in Pennsylvania. Locations across the Laurel Highlands have just picked up some fresh powder, 2-7inches, from some lake effect snow Friday night and conditions look to be great through next week. Blue Knob is reporting 85% operation of trails with other locations reporting up to 100%. Ski conditions across south-central Pennsylvania are the best in a decade with Roundtop, Whitetail, and Liberty reporting nearly 50inch snow bases and full operation under some new snow from last Wednesday and a bit Friday afternoon and evening. Conditions across the Poconos and northern Lehigh Valley are excellent after nearly 7-9inches of snow fell from midweek. Shawnee Mountain is report 100% of the trails open with a 72inch snow base that is not going anywhere until late May. Blue Mountain ski is reporting 98% operation with even 20 lanes of snow tubing going on. Camelback is reporting great conditions along with other ski resorts. Take advantage of the next seven days as these great conditions will not last forever. For once it seems like ski resorts are not struggling in the snow department this year.
-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 2/1)
Well Lake Erie froze over just about completely this winter, which hasn't happened in a few years. This has limited lake effect snow outbreaks for the past few weeks and this looks to continue. It does appear there is the potential for some lake effect snow for this coming week. As a low pressure pulls out to sea the flow will turn northwesterly near the 310degree trajectory. This will be towards Tuesday and Wednesday. Meanwhile as that trough is departing a ridge will be moving in from the Mississippi Valley keeping the flow northwesterly. With Lake Erie generally frozen over and with ice on Lake Ontario and Huron this outbreak will not be too widespread nor strong. H85s will near -15C or potentially colder for a time. Looking at Omega fields near Bradford there does appear to be some weak omega and with dendritic growth. This should result in ample snow growth with ratios up to 20:1 in some areas. Western and northern facing ridges will see the most lake effect snow likely across the Northwest Mountains. The flow does not quite appear westerly enough for widespread bands in the Laurel Highlands. Snow accumulations should range in the moderate category likely 3-6inches with isolated amounts in Warren, McKean, Erie, and Crawford Counties near 8inches. Snow accumulations across the Laurel Highlands and North Central Mountains will be more on the order of 1-4inches. Some snow showers and flurries should be able to make it east of the mountains at times also with a possible coating or two along the Raystown Lake-Lewistown-State College-Williamsport line. Also across the northeastern mountains in Bradford and Wayne County there could be some streamers as flow is northerly during the day Tuesday. 1-3inches of snow will remain possible. Overall though this snow should just be a nuisance for snowbelts.
"Current Lake Erie Wind Direction and Speed"
(Courtesy of NOAA)
"Current Lake Erie Water Temperature"
(Courtesy of NOAA)
"Long Term Outlook" (Updated 2/1)
While it sure looks like the cold of winter and snow of winter is here to continue from looking outside the window, this does not seem to be the case starting late next week. An extended relaxation period looks to be upon us. Looking across the Globe it seems that extreme brutally cold air is hard to find. Across the North Pole there also has been above normal temperatures resulting in no increase in ice cover in the past week or two. It appears the cold air will retreat back across the northern including Alaska. An Alaskan vortex also looks to form during this time making it very unlikely for a major east coast snowstorm in the first week in February. Currently looking at the MJO we are in an unfavorable phase 3 which tends to keep troughing across the northwest and not the eastern CONUS. There does seem to be a progression of the MJO pretty rapidly into 4 and 5 this first half of February which still is quite unfavorable. But by the time mid February works around we could be looking at maybe phase 6 or 7 as indicated by the GFS operational and GFS ensembles. Latest ENSO reports show some warming across the equatorial Pacific and it appears the strongest of the La Nina is over, which is optimistic. Teleconnections remain unfavorable for any extended cold air during the first two weeks of February, but snow cover may help to keep the temperatures more moderate than mild. One thing to note is that the models have shown this warm air progged quite often in this time frame and never come to fruitation. But it does appear this time that we are headed for a more mild spell with less frequent snows. In all honesty I am sure the general public won't mind that forecast. Heading towards mid February it does appear things head a bit more colder and snowier with time.
"Current NAO and PNA Predictions"
(Courtesy of NOAA)
"Monthly Outlook" (February)
Well January finishes on quite a cold note continuing the trend for my winter outlook of below normal temperatures. I am very pleased with my forecast for January of below normal temperatures and normal snowfall. All climate reporting locations in Pennsylvania have reported a below normal mean generally in the (-2)-(-5). Snowfall for the month came in below normal for southern and eastern areas thanks to some mixing. But other than Philadelphia anomalies for snowfall were not really too far off typical means. Lake effect snow belts reported above normal snowfall for January along with northern Pennsylvania which saw well above normal snowfall. Overall January went relatively according to plan. February's forecast does not look quite so easy to forecast. February is the last month for my winter forecast that consisted of December, January, and February and the month looked to be volatile in terms of pattern. Looking at teleconnections the CPC NAO index does report a negative reading for the first half of the month. But looking at heights up towards Iceland it seems that this will be an east based negative NAO which does not really help winter storms for the eastern CONUS. When the models were progging our inland superstorm the low bombed out to near 950mb across northern Canada and changing the overall pattern. Large systems like that generally are pattern changers. So when this 950mb low headed north it shifted the negative NAO to a more favorable west based negative NAO. This no longer seems to be the case. Looking at the PNA it is headed negative giving way to an unfavorable negative state making the Pacific a thorn in our side to try to get any winter storms. The only positive thing I can find in the teleconnections is the highly negative AO progged by mid month. But with a lack of cold air across the northern Hemisphere this may be difficult to occur. The MJO looks to be in unfavorable phases during this month for eastern troughing. It also appears again we have an active northern jet stream which will favor southwest flow events, overrunning systems. This leads me to believe a lower confidence than normal monthly outlook.
Temperature- I am going to take a risk and go against what has been the case this entire winter. I am forecasting normal to above normal temperatures. Above normal temperatures should range from (+2)-(+4). Areas at most risk for above normal temperatures will be south of I-80 as a weak trough may hang up over New England keeping those areas cooler including northern Pennsylvania. The first half of the month definitely looks to be more mild than towards mid month when potentially colder air works in.
Precipitation- Precipitation wise I am going with normal precipitation with normal to below normal snowfall. The northern jet should be active, but with lacking surface features and teleconnections it should be harder to get all snow events. This does not mean a large snowstorm is not possible because towards the 10-12 there have been some indications of potentially a snowstorm. Also with the lakes just above frozen over, this will limit lake effect snow. In any case February is typically the snowiest month for Pennsylvania, so I guess we will see what happens this month.
"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- .75inches of snow
Monthly Total- 2.85inches
Seasonal Total- 21.30inches
Winter Weather Advisories- 6
Winter Storm Warnings- 2
Ice Storm Warnings- 1
Blizzard Warnings- 0
Freezing Rain Advisories- 0
Winter Storm Watches- 4
Lowest High Temperature- 14degrees
Lowest Low Temperature- -3degrees
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 - 3.50inches
Clipper - January 17-19 - 1.50inches
Synoptic Snow - January 27/28 - 4.00inches
Lake Effect Snow - 2.00inches