Major East Coast Snowstorm Possible...

By: Zachary Labe , 1:57 PM GMT on February 28, 2009

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Thoughts on February 28-March 2 Storm...
A major coastal storm will be working along the Middle Atlantic coastline during Sunday night through Monday. Early morning water vapor loop shows increasing moisture across the southeastern states with an impressive 500mb cutoff vortex across the extreme deep south almost as far south as the Florida panhandle. This is causing a deep surge of cold air with snow being reported well into the southeast gulf states. Winter weather advisories have been issued for the Atlanta metro area for 1-3inches of snow. Interestingly enough this is the second time this year snow has occurred much farther south than climatologically favored snow locations. Surface maps indicate a gathering low pressure across Georgia. This low will lift northward along a frontal boundary and move northeast along the coastline keeping a favorable track for an all snow scenario. A cold Canadian high will funnel in northwesterly winds to all of Pennsylvania along with dry air which will inhibit widespread moisture, but instead it will provide all snow for all of Pennsylvania. There is no mid-level warming in this storm system for once. Upper trough begins to become negatively tilted as low pulls up the coastline causing the low amplify. There is still some question to what and how much amplification takes place in the early stages of this storm as it will have a result in how far the precipitation gets in the west. Strong frontogenisis occurs in eastern Pennsylvania early Sunday evening as moisture pulls into the region. Deformation axis looks to be across extreme eastern Pennsylvania with the hills of Chester and Bucks County getting the brunt of the banding. Some mid level instability will promote high snow rates of 1-2inches for much of the event in these areas along with the possibility of thundersnow. 700mb RH charts indicate a non-gradual boundary between snow and non-snow which will likely setup near the Harrisburg area up through the northern Poconos. This area is where the highest bust potential exists with the possibility of more or less snow than being forecasted. No snow is expected from a line of Chambersburg-Lewistown-Mansfield and westward. Instead these areas will be seeing just some high cirrus clouds under a cyclonic flow. As the low strengthens to near 1000mb off the coast the tight pressure gradient will promote high winds in many locations causing blizzard conditions especially across far eastern Pennsylvania. The snow will be powdery as snow ratios especially in western areas will be near 15:1. Overall the event favors extreme eastern Pennsylvania for heavy snow with a prominent cutoff zone near the Harrisburg area. Isolated totals of 16inches are possible in a few higher elevations above 700ft in far eastern Pennsylvania.

Timeline...
3-5pm... Clouds will begin to thicken across southern Pennsylvania after any breaks in the clouds early afternoon. Temperatures may be slightly above freezing for most locations, but with colder air funneling in they will drop below freezing as the precipitation moves into the region.

5-9pm... As isentropic lift occurs to our south. Light snow will begin spreading into southern and eastern parts of Pennsylvania. Temperatures during this time will still be right around freezing preventing roads from too much accumulation for the initial light snow. As heavier precipitation moves in travel will become highly discouraged. Snow amounts in this period will range around a coating to up to one inch.

9pm-12am... Heavier precipitation will work into the region along with enhanced banding in many locations across eastern Pennsylvania. Snow rates may approach 1inch per hour in some locations. Roads will quickly become snow covered. Temperatures will fall into the 20s statewide. Snowfall accumulations will be 2-4inches in far eastern areas with 1inch across the west.

12am-4am... This period will feature the heaviest snow with rates approaching 3inches in one hour for a few isolated locations. Thundersnow can also not be ruled out for the I-95 area. Snow accumulations will range from 3-5inches in the east and 1-3inches in the west. Temperatures will fall into the low to mid 20s and winds will begin to become gusty. Blizzard conditions cannot be ruled out for a period in far eastern areas.

4am-8am... The morning commute will feature the main banding pull northeast of the region with additional snow accumulations of 1-3inches statewide. Winds will remain gusty with blowing and drifting snow with limited visability.

8am-12pm... The final burst of snow will approach with an upper level low along the western flank of the storm with a period of light to moderate snow across eastern Pennsylvania. Additional snow accumulations may be 2-4inches for many areas. Temperatures will continue to fall with increasingly windy conditions.

Radar...
Radar...

Warnings...
Warnings...

NAO...
NAO...

This is my current rain/snow line...
This storm will feature very far south in comparison to storms of the previous few winters. This sleet/snow line is for the period at the height of the storm for these locations. To the north of the line will be snow and to the south will be more of a mix or rain.

My sleet/snow line is... Greenville, SC - Charlotte, NC - Fayetteville, NC - Goldsboro, NC - Wakefield, VA - Salisbury, MD - Lakewood, NJ

*Note these lines are estimates and actual locations may vary.

Storm Reports...
None.

Storm Impacts...
1. Periods of very heavy snow in mesoscale banding.
2. Snow rates of 1-2inches across far eastern Pennsylvania.
3. Blowing and drifting snow generally after the storm.
4. High impacts to metropolitan areas of eastern Pennsylvania.
5. Sharp-cuff of snow/no snow between Reading and State College.

Snow Map...

*Note this does not include snow amounts from the first wave.

Selected City Accumulations for the Northeast...
Hagerstown, MD- C-2inches of snow
Baltimore, MD- 5-9inches of snow
Washington, DC- 5-10inches of snow
Wilmington, DE- 6-12inches of snow
Dover, DE- 5-9inches of snow
Cape May, NJ- 3-7inches of snow
Trenton, NJ- 8-14inches of snow
New York City, NY- 5-10inches of snow
Poughkeepsie, NY- 6-12inches of snow
Binghamton, NY- 2-4inches of snow
Albany, NY- 2-5inches of snow
Hartford, CT- 9-15inches of snow
Concord, NH- 6-12inches of snow
Providence, RI- 8-12inches of snow
Worcester, MA- 9-15inches of snow
Boston, MA- 6-12inches of snow
Nantucket, MA- 3-6inches of snow
Hyannis, MA- 3-7inches of snow
Portland, ME- 6-12inches of snow
Bangor, ME- 8-12inches of snow
"Subject to Change"

Model Analysis
Instead of looking at each model, I am going to show maps that helped support my forecast from each model. The low will be forming across the southeast near the coast of the South Carolina coastline. Low pressure will track to the northeast. The GFS seems to have a pretty good hold on the precipitation shield and low strength. Although the low does seem a bit stronger and more amplified looking at infrared satellites and the water vapor loop.

As the low tracks there will be a sharp-cutoff between snow and no snow. 700mb charts indicate the best relative humidity to be across eastern Pennsylvania.

While QPF will be lighter in the western side of the precipitation shield, snow ratios will be better as colder air comes rushing into the system. I was looking at the snow from last night and it is very dry with a low moisture content made up of dendrites. Omega growth and dendritic growth is superb for this event with best dynamics found in the mesoscale bands that are likely to form overnight Sunday. While the best frontogenisis remains to our south it does appear there will be an intense band of snow over eastern Pennsylvania.

500mb charts are classic for the entire event with a sharp negatively tilted trough and a deep 500mb vortex to the south. Jet streak is located in eastern Pennsylvania and that will be associated for where the heaviest snow will fall.

Overall it looks like a classic nor'easter is headed towards the Northeast.

After the storm...
Monday- Coastal low near benchmark will be pulling to the northeast. Deformation band of snow will remain parked across eastern Pennsylvania with heaviest snow likely in extreme eastern portions of the state. For a time Monday morning snow could be quite heavy in far eastern areas. Disturbance with weak associated cold front boundary will move by afternoon pushing the system out of the area and bringing in much colder air. Dewpoints will drop below zero for the mountains with temperatures below freezing statewide. Winds will be quite gusty under tight pressure gradient causing windchills in the single digits. This will likely be the coldest day during the next 9-10 months. Under the week upper air disturbance snow showers will persist across the state with some light snow accumulations possible in the Laurel Highlands and northwest mountains. Monday night will feature lows dropping in the single digits for much of the state under a gusty 20-35mph northwest wind. Wind chills will be near advisory criteria for the mountains. Partly cloudy skies will prevail.

Tuesday- Tuesday will feature partly cloudy skies statewide. A few snow showers will be across the Laurel Highlands during the day with a few coatings of snow possible. A low strato-cumulus deck will prevail across the higher elevations above 2000ft. Downsloping winds will result in sunshine for eastern areas along with a fresh snow pack making air temperatures quite cold. Highs will generally be below freezing statewide with some blowing and drifting of snow in the morning under breezy conditions. Tuesday night will feature clear skies and breezy conditions. A few cirrus and cumulus clouds may work overhead overnight as a weakening disturbance moves to the north. Lows will drop in the teens and single digits statewide.

Wednesday- High pressure remains in control across Pennsylvania with sunshine. Temperatures will be warming up back to the low 40s and upper 30s for most areas which is still slightly below normal. Wednesday night winds will begin to calm combined with low dewpoints which could make for some very cold temperatures in the sheltered valleys. Lows will work down in the teens and single digits once again.

Thursday- Departing high pressure will keep generally sunny skies statewide with some warming of the air temperatures. Melting snow will be occuring statewide. Highs will be near seasonal values with highs in the mid 40s across the south and mid to upper 30s across the north. Thursday night clouds will moves in and thicken from west to east ahead of the next storm system. Some light rain may move into western Pennsylvania after midnight with amounts generally less than .1inches. Lows will be in the mid 30s across the west to around freezing in the east.

Friday- Low pressure moves across the western Great Lakes into Canada with a slow moving cold front with limited moisture. Light rain showers will persist throughout the day with totals less than .25inches for all areas with most areas much less than that even. Stratus deck will lower over the higher elevations with ceilings below 1000ft causing for some IFR conditions at the local airfields. High temperatures will be mild under southwesterly flow across western Pennsylvania in the 50s, but eastern Pennsylvania will still be under easterly flow keeping highs cooler and in the 40s thanks to departing high pressure in the Canadian Maritimes. Friday night will feature cloudy skies and light drizzle and rain showers. Lows will be mild and well above normal generally in the upper 30s statewide.

Please post storm reports in this blog from across the Northeast during the winter storm...
This blog is in progress. Check back soon...

"Here northeast of Harrisburg 2008-2009 winter statistics"
(Snow Stats)
Current Snow Cover- 2inches
Monthly Total- 3.00inches
Seasonal Total- 25.40inches
Winter Weather Advisories- 7
Winter Storm Warnings- 2
Ice Storm Warnings- 1
Blizzard Warnings- 0
Freezing Rain Advisories- 0
Winter Storm Watches- 4

(Temperature Stats)
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
Coastal Storm - 2.00inches

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so Blizz, I am guessing the storm from last night went farther than the 70/40 benchmark? what happened? it seems like the 95 corridor didn't get anywhere need what was predicted
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Well I guess the makes Harrisburg the only city yet to have a 6inch+ snowstorm this winter, hahahaha.
Member Since: December 14, 2007 Posts: 285 Comments: 15142
Wow, some impressive isolated totals. 15inches is actually the highest I have heard for any area across the whole Northeast so far!
Member Since: December 14, 2007 Posts: 285 Comments: 15142
Blizz will be very jealous of your snowfall total. we haven't had anything close to that in a good while. the last time we were double digits (10.5") was March 17, 2007.
i wouldn't want the power outages though. you have to give Blizz your address so he can send the trophy. lol
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Just featured us (Leonardtown, MD) on WUSA9 tv. 15 inches of snow, 44 trees down, local HS opened as shelter due to power outages.

They said we were the 'winners'! for the Balt/Wash area snow totals.
Member Since: Posts: Comments:
sounds like a great couple of days for you MG. 60 degrees would be nice for us, but i think we will be upper 40's to low 50's
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Quoting TheRasberryPatch:
just don't let it happen again weathergeek. hahaha
what was your total for the two days?


7.0 for the 2 days.
Member Since: December 25, 2005 Posts: 0 Comments: 1744
RP --The county does not have much equipment and hires outside contractors to help. BUT-the plows did all the streets around us and missed us! We are on a short end of street with 7 houses, usually we get plowed Ok. They have already cancelled school for tomorrow so I am sure there are many streets like ours, and there were power outages in the county. Snow took down some trees. 60 degrees by end of week.
Member Since: Posts: Comments:
no plows today MG. wow. i thought penndot was bad. usually maryland is very good with snow removal. must be your county not used to the snow. haha. they must think they live in georgia or bama or texas.
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Hey Blizz,

Decent storm for me. 12" plus or minus. The wind is gusting upwards of 35 mph. Drifting has been pretty impressive.
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just don't let it happen again weathergeek. hahaha
what was your total for the two days?
Member Since: January 26, 2007 Posts: 72 Comments: 6276
We are finaly in for the nite. Cold but beautiful here.
Only one problem-road never got plowed. I expect them after dark so we will have that pile of ice at the end of the driveway in the am. Small price to pay for such a great storm. I will post more storm pics tomorrow.
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Today I got 6.5 inches of snow. I will take it!!! Right now it is 22 degrees with Windy conditions. Raspberry Patch I learned my lesson!!
Member Since: December 25, 2005 Posts: 0 Comments: 1744
Blizz - did you see today was tornado advisory day?
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Hey Blizz. I have been in a favorable position for a few of these systems.

it is amazing how Hagerstown has that little bit of snow for the season. they are up in the mountains and usually below freezing when most are just above freezing. that goes to show this season has been weird for storms. i don't even think any storms came up through baltimore or a bit west or up the chesapeake. that usually happens a few times of the year.

Member Since: January 26, 2007 Posts: 72 Comments: 6276
hurigo- You are actually getting a rare phenomenon. Bay effect snow. North winds are drawing moisture from the Chesapeake Bay and bringing snow snow showers into your area.

Snowlover2010- See all that worrying, lol. 5inches was right on forecast. Anyways roads should be fine tonight, just patchy black ice, but even there shouldn't be too much of that.
Member Since: December 14, 2007 Posts: 285 Comments: 15142
how bad will blowing snow be now? will roads be covered again tom morning?
Member Since: January 7, 2008 Posts: 2 Comments: 1003
got about 5in bliz
Member Since: January 7, 2008 Posts: 2 Comments: 1003
Oh has it been cold today. Did not get out of the 20s. we got a light layer of snow, which is slickly frozen. Temps steadily dropped during the day from 37s to current about 27. Some melt when the sun shortly visited. It's snowing now--well actually it is little white flying specs that seem to have no direction or steering control.
Member Since: October 9, 2005 Posts: 100 Comments: 6748
MarylandGirl- Nice pictures, hope you are enjoying the snow!

TheRasberryPatch- I remember you were commenting on Hagerstown, MD during another snowstorm. I was looking at their seasonal total, it is only 6inches this winter.
Member Since: December 14, 2007 Posts: 285 Comments: 15142


Here are the birds at the feeder right after we filled it.
Member Since: Posts: Comments:
TheRasberryPatch- Interesting article. The last part is very interesting about the defective satellite, ha.

PalmyraPunishment- I do not know. The pattern looks somewhat favorable mid to late March, but climatologically speaking that is not the best time of year for snowstorms for Harrisburg, but they do occur. I feel for you guys on the west shore. You really have missed quite a many snows this winter. Rasberry and Snowlover are getting the high totals.
Member Since: December 14, 2007 Posts: 285 Comments: 15142
it came down really hard this morning blizz. the ULL had a nice thick yellow line on the radar this morning that was north or me down to baltimore. so far on your blog it looks like MG is the winner easily.
hope you get to read George Will's comment.

snowlover - the only thing would be refreeze
Member Since: January 26, 2007 Posts: 72 Comments: 6276
so, would it be safe to assume that this was our last hurrah for this season?

i think ive finally grown tired of the cold and wind for now. with us "springing forward" this weekend, i'm ready to break out the shorts!
Member Since: January 31, 2007 Posts: 9 Comments: 2250
TheRasberryPatch- Boy, you have beaten me quite a bit in snow totals the last couple of events. I was on the cutoff anyway over here, my snow map had 3 different totals for Dauphin County, so it was to be expected I was close.

Snowlover2010- All done! Snow total there?


*Thanks all for your reports. Finally a storm that cooperates.
Member Since: December 14, 2007 Posts: 285 Comments: 15142
so funny story. our superintendent came around to all our classes today and said that having school was a stupid move on his point and explained why he did it. so many accidents today. there is no way we should have had school. now at the end of the day they said some stuff would happen with a 2 hour delay tom. is something supposed to happen tonight?
Member Since: January 7, 2008 Posts: 2 Comments: 1003
only 2" huh Blizz. oh well. it came down really hard for 2 hours here this morning. the birds have been flocking to my feeders today.
if you get the chance check out the link on post 381. it is very very interesting.
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Well sounds like my snow map panned out for the most part for most all areas east of the immediant Harrisburg area. 2inches of snow here.
Member Since: December 14, 2007 Posts: 285 Comments: 15142
What a storm for you MG, huh. some advice on the sledding run. if you have a 5 gal bucket fill it with water. add snow to it and put it down on the sledding run. you are making slush. let it freeze before riding on it. it make take a few trips with the bucket to get a nice icy build up. also spread it out. it doesn't have to be ice all the way. come this evening when it is dark that sled run will be perfect.
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Still snowing here, measured 14 inches on the neighbors deck. Have been shoveling, cleaning vehicles, and got in some sledding. actually we tried to compact it for the neighborhood kids. Still have not seen a snow plow on our road. Time for some lunch.
Wonder when it will end here, radar looks like it should end soon but I thought that an hour ago and it is still coming down good.
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if you look at the super doppler there is a bit more coming up from maryland. not sure if it will get up into PA or not
Member Since: January 26, 2007 Posts: 72 Comments: 6276
All we ended up with in Lawnton, just south of Harrisburg was about .5 inches. It is starting to clear a little and getting windy.
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hello eng - did the beaches get as much. you are so right about open fields where you are located. i have driven through some roads in sussex county during a big snowstorm and there can be some huge drifts.
Member Since: January 26, 2007 Posts: 72 Comments: 6276
8-9 inches here in Magnolia, DE just south of Dover. The wind is really whipping. We have had some gusts over 50mph. Everything is shut down today. My guess is drifting snow will make travel difficult into tomorrow. We have lots of open fields here, so the roads will keep drifting shut. Lost power for a few hours last night. Thank goodness for our wood stove! Lunch, then play!! Everyone stay safe!
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About 8 inches here. Sledding round 1 done and somewhat successful. Round 2 coming up soon at local golf course. Still snowing here lightly. Intensity actually picking up and radar returns back it up. A strange tail end of snow reappearing south of me. Perhaps another inch or two as a surprise? That would make us very happy here.

HeavySnow, somewhat satiated
Member Since: July 7, 2004 Posts: 18 Comments: 2998
the snow is dwindling down with flurries and blowing snow. the sun is peaking through the thining clouds.
i recieved 6" of snow all this morning and the majority of it coming in a 2 hour span

it is very cold using the snowblower. glad it didn't take me too long
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Hey Blizzard. This is absolutely beautiful. Schools are cancelled all over the region. A good 6-7 inches accumulated here, with some surprising totals near the shore. In Cape May, they got 5 inches, quite a surprise considering snow is rare there. The most appears to be in Vineland, NJ with nearly 13 inches, a good 45 minutes away from me. We're just about finishing the last band, and it's somewhat mixed in with some blowing snow to create the illusion that it's snowing more than it really is. How much snow did you get in central PA?
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well the birds are back flying around and coming to the feeders. snow is very light

Blizz - i hope you get the chance to read George Will's commentary on Global warming. too funny. here is the link

Link
Member Since: January 26, 2007 Posts: 72 Comments: 6276
the snow has definitely let up. not nearly as hard as earlier, but still close to an inch/hour. well Blizz had the snow map on target for my area, unless the snow amplifies even more and i get another couple more inches - hahaha
his timeline wasn't on target, but expecting this ULL was right on.
Member Since: January 26, 2007 Posts: 72 Comments: 6276
if you look at the radar the yellows have been moving east slowly and here where i am i have been in the yellows most of the time it has been snowing - since just before 7am.
PP - it has been like this since 7am.
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Still snowing, but only about 0.5 inches on the ground here in lawnton. A very dry snow with small flakes.
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it's really coming down...

i think we're going to salvage a respectable snowfall out of this one.
Member Since: January 31, 2007 Posts: 9 Comments: 2250
I just measured and now have 5" of snow on the ground. its hard to get a good measurement with the snow so fluffy, but i am looking at my snow gauge and it is just under 6
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Made it to work - 8:20 AM.

I left Carlisle at my normal time. As I left it was snowing at a moderate pace, very windy. Roads were perfect for driving from 641 to I-81 for the entire duration.

743 between Grantville and Hershey was covered in snow, but not bad for driving - however from Lingle Road at 743 until I stopped at work the roads were horrific, even for my Blazer.

3 inches of snow in Palmyra, it's coming down at a rate that I would assess as roughly 3 inches per hour and still falling. Palmyra's roads are of 2 conditions -- slush covered (see also: crap) and snow covered (see also: great).

This was our storm, folks -- we have been crying for a coastal for 2 winters now... and when it finally came -- we still got the snotty end of the ole' eff-stick. Let's just see if we can salvage a decent snowfall out of the remains of this event.
Member Since: January 31, 2007 Posts: 9 Comments: 2250
PP - did you make it in to work? i can't imagine the roads in my area being any good. i wonder what PP's assessment will be about the roads
Member Since: January 26, 2007 Posts: 72 Comments: 6276
i am getting hit hard SSA and lawton. after a night of seeing nothing it is making up for it now.
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Quoting PalmyraPunishment:
Oh look... grass...

*clears throat*

The Lower Susquehanna Valley - Where storms go to die.
I knew we weren't supposed to suspect much, or really even anything, but damn it anyway.
Member Since: December 1, 2008 Posts: 0 Comments: 600
MG it looks like you were close to the center of the heavy snow band. We only have a dusting on the ground this morning around Harrisburg, PA. but it is still snowing.
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i just measured and got a little over 3" and that is just over an hour of snowing.
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Have picked up another 1.5 inches this morning. Breakfast first then out the door to enjoy.
RP-glad you are getting it too.
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Mmmmmmmmm MG sounds good. I didn't cook any bacon this weekend and am hungry for some.
that snow is coming down hard here too MG. very low visibility
Member Since: January 26, 2007 Posts: 72 Comments: 6276

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Cornell University- Atmospheric Sciences Undergrad; Research Assist.- Onset of Spring Indices Toolbox; Interests- Small spatial scale climatolology

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