Colder conditions and snow potential this weekend...

[WXBUFFJIM]

As we round out the week and head into the weekend before Christmas, there is likely going to be snow and extreme cold in the forecast across most of the eastern and central part of the nation. Cold and wind is a guarantee. The uncertainity comes in the evolution of a ocean storm along the east coast Sunday into Monday. Right now the track is far enough offshore that the megalopolis will likely be spared a significant snow. But the upper dynamics still needs to come through with a light snow accumulation potential for Philly, Baltimore, and Washington points north and east.

Detailing this situation day by day, a strong cold front will plow through Minnesota, Wisconsin, and the Upper Peninsula of Michigan later Saturday into Saturday night. Behind the arctic front, temperatures will drop to about minus 20 degrees in the arrowhead of Minnesota including Embarass and International Falls. This combined with strong winds could bring winds chills down to minus 40 degrees in northern Minnesota including the arrowhead. Further east into the Upper Peninsula of Michigan, a winter storm watch is up for late Saturday into Sunday as strong northwest winds bring temperatures down into the single digits, wind chills down to 25 below zero, and the end result will be a huge lake effect snow event with possibly up to 18 inches of snow possible particularly in the higher terrain of the upper peninsula from Skandia to Trenary and Steuben. A significant lake effect snow event is also expected Saturday night through Monday in lake effect favored areas of Lakes Michigan, Huron, Erie, and Ontario as well.

By Saturday night expect light snow along the arctic front to impact lower Michigan and also the Chicago area and the Quad Cities and falling temperatures. For example Chicago is expected to drop to 10 degrees in the city with single digits north and west Saturday night along with that chance of snow. Highs Sunday in Chicago will likely stay in the mid teens with strong northwest winds and dangerous wind chill readings of minus 2 to minus 16 degrees. A slow moderating trend is likely by later Monday for Chicago.

Further west into the Quad Cities area, a very cold night Saturday night with lows in the single digits and a chance of light snow or fluurries along the arctic cold front. High temperatures Sunday in the Quad Cities will likely remain in the single digits to close to 10 degrees and then drop to near zero Sunday night. Wind chill readings during this time potentially could be as low as 5 to 15 degrees below zero. A moderating trend is likely later Monday for the Quad Cities vicitnity.

While a brief respite from the arctic air is expected Monday through Wednesday in the upper midwest, a more significant arctic blast is likely Wednesday night through Thursday with dangerously cold wind chills. More on that later.

As this arctic front plows through the Ohio Valley and the southeastern United States Sunday into Sunday night, this will likely be accompanied by a strong upper level disturbance. This upper disturbance will likely bring snow to areas of the southeastern states Sunday and Sunday night. This could mean a light coating in Atlanta with an inch or two north of Atlanta. Higher snow totals are possible along the west facing slopes of the Appalachians. At the same time this occurs, very cold temps will dive into the southeast including Florida. Sunday night could feature a hard freeze for northern Florida and Monday night could feature a hard freeze for northern and central Florida including Tampa and Orlando. Frost is even possible Monday night down to the inland areas west of Miami over the Everglades.

While the arctic chill and strong north and northwest winds are a certainity, the question is what about an east coast storm? Yes this storm will form in pieces. The first weaker system will form later tonight off the Carolina coast and head north northeastward towards the general direction of Cape Cod. Areas north and west of Boston including parts of Maine could experience a light coating of snow Saturday as this weak wave of low pressure passes by. The bigger more impressive system is expected to form later Sunday along the Delmarva coast and head towards the general direction of Cape Cod or just offshore from there on Monday. Should heavy snow occur from this coastal system, it appears Boston and Portland, Maine are targeted for the heaviest of snow and the emphasis is a few inches as opposed to a couple of feet of snow in this area. But there is still possibility that this coastal system misses New England altogether giving those area little if any snowfall.

Meanwhile for areas further down the coast, the focus is not much the coastal storm, but a strong upper system that should pass by just south of Washington DC Sunday night into early Monday. Areas north of this upper storm could experience a light coating of snow including Washington, Baltimore, and Philadelphia. Should this occur, this particular area of the country will see their first measureable snow of the season. While 1-3 inches seems possible for Philly, Washington, and Baltimore, it does not appear there will be much more than that UNLESS the coastal storm develops closer to the coast. We still need to pay close attention to the megalopolis because the exact track and intensity of this storm is still unclear. We saw what happened on January 20th, 2000 when the National Weather Service mentioned very little snow for the megalopolis, then BANG there was a 20 inch snowfall from the shores of the Chesapeake Bay northward to coastal New England.

No matter what occurs for the megalopolis whether it snows or not, it will be windy and extremely cold Sunday night into Monday. High temps Monday may only stay in the 20s from DC up to Boston with wind chills in the teens and single digits. If we experience snow cover, temps maybe even colder than advertised.

So again the big story is extreme cold this weekend and into Monday, which will be brief and short lived. At the same time a significant lake effect event is likely in lake effect favored areas as cold northwest winds roar over relatively warmer lake waters. Finally the coastal storm at this point does not appear to be a significant threat to the east coast. While snow is likely from the upper disturbance associated with this storm, it appears not much will accumulate in the megalopolis except for a light accumulation. Part of the reason for this perhaps could be the fact the NAO is positive, so cold air that is invading the United States will be brief and short lived as described earlier. A negative NAO would mean longer more prolonged cold snaps. We're also missing the Greenland blocking high, which again diminishes the chances for a significant east coast storm along the coast. But we've seen times when there were exceptions to that rule, which is why the amount of cold air as well as the exact track and intensity are key elements as things evolve over the next few days. Stick around.

Jim

[CaptinCrunch]

KICH A$$ FOOTBALL WEATHER!!!!!!! let the snow fall hard and heavy!!

[WXBUFFJIM]

Looks like since the upper disturbance is expected to pass south of Washington DC, snow will be likely from Washington DC and Baltimore up to Philly and maybe New York as well. At most a few inches of accumulation would seem likely with a widespread 1-3" coating. A few areas within this corridor could see more than 3", but that seems to be isolated at this point.

The bigger story we must keep in mind is temperatures and wind chills. For example low temps Sunday night in Baltimore will be near 20 and highs Monday will stay in the low to mid 20s as opposed to what we're experiencing today with highs near 50 degrees. Wind chills could easily be in the teens and single digits Sunday night and Monday for the Baltimore vicinity. Then we focus on what the implications of the coastal storm has on New England on Monday. While a blockbuster snow is not expected for the megalopolis, a coating or a few inches could easily occur from DC to Boston.

Winter is definitely here for much of the United States and the worse of winters brutal sting maybe coming up in the coming weeks.

[nin9inch9nails]

Nice analysis..thank you.

[CaptinCrunch]

Looks like from the upper disturbance passing south of Washington DC, snow will be likely from DC and Baltimore up to Philly and maybe New York as well. At most a few inches of accumulation would seem likely with a widespread 1-3" coating. A few areas within this corridor could see more than 3", but that seems to be isolated at this point.

The bigger story we must keep in mind is temperatures and wind chills. For example low temps Sunday night in Baltimore will be near 20 and highs Monday will stay in the low to mid 20s. Wind chills could easily be in the teens and single digits during this time period. Then we focus on what the implications of the coastal storm has on New England on Monday.

Winter is definitely here for much of the United States and the worse of winters brutal sting maybe coming up in the coming weeks.

The Patriots play @ Miami Monday Night!!
But they will play @ NY Jets the following Sunday

[rainstorm]

MISERABLY cold and windy here, with no snow. the wrost possible weather

[KWT]

good to see you lot over in the U.S getting some snow possilby.

As for me in the U.K,simular story this weekend looks like it could be quite cool/cold as we get northerly winds,we'll also get a frontal system from the SW and on the systems northen side it'll turn to snow,before the front moves back south again.

also our first real cold night is upon us on Saturday and Sunday,with some areas dipping down to 17.6F.

[Anonymous]

I'm stunned..............I never really expected this degree of cold weather here so early in NE Virginia. Wow, highs in the low/mid 20s Monday with 20 to 30 mph winds and gusts to 40?

That's unbelievable here in mid December. What's more, we already hit 18 degrees for a low a few days ago, which was shocking. We usually don't get below 20 degrees for a low until January. Now we will have HIGHS in the 20s on Monday?

What kind of a winter is this going to be anyway?!!!

-Jeb

[Wpwxguy]

http://grib2.wxcaster.com/CONUS_GFS_SFC ... _180HR.gif

check this out...........

[JenyEliza]

This upper disturbance will likely bring snow to areas of the southeastern states Sunday and Sunday night. This could mean a light coating in Atlanta with an inch or two north of Atlanta.

WOO HOO!!! Sounds good to me! We've got some last minute Christmas things to do around the house, so some light snow should set the mood perfectly!!

Jeny

[JenyEliza]

http://grib2.wxcaster.com/CONUS_GFS_SFC_SNOW-DEPTH_180HR.gif

check this out...........

OMG!!! If this verifies, we're in the 4-10 inch range. WHITE CHRISTMAS? O MY!!

WOO HOO!!! Looking like maybe a Jen-Walk in Atlanta?

Jeny

[Anonymous]

I am going to be enduring one heck of a frigid jebwalk on Monday. There may even be a bit of snow (not much, probably a coating to a half inch) blowing around.

Such cold for mid December!!

-Polar Jeb BRRRRR!!!!!!!!

[yoda]

I am going to be enduring one heck of a frigid jebwalk on Monday. There may even be a bit of snow (not much, probably a coating to a half inch) blowing around.

Such cold for mid December!!

-Polar Jeb BRRRRR!!!!!!!!

Being the amateur forecaster that I am Jeb.. I see more than just 1/2 inch... I see around 2"... WWA criteria IMO. We will see though what really happens...

[Tip]

After reviewing latest trends in the models, it seems that the first storm Sun-Mon is a minor event for most of the east coast save extreme eastern SNE. Then there is a brief bitter cold shot to the east. During the middle to latter part of next week the mean trough retrogrades to the other side of the Mississippi and takes op residence allowing the cold air to drain into central US. The next storm cuts up west of the Appalachians with the second storm slightly more east as it is deflected by high pressure in the upper central US. This storm has a better chance to deliver wintery weather further east if the trough isn't too sharp on the eastern side. After that the CONUS pattern may breakdown into a zonal flow unless the NAO can be coaxed into going negative.

http://meteocentre.com/models/ecmwf_ame ... 9panel.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_372s.gif

[Wpwxguy]

This statement from Jackson MS nws office concerning the coming Christmas cold. Still no mention of snow, thats something that we'll have to watch.

BIGGEST NEWS STILL WILL THE COLD COLD CHRISTMAS WAITING IN THE WINGS.
MEDIUM RANGE GFS RUNS HAVE TRENDED EVEN COLDER THAN PAST TWO DAYS WITH
THICKNESS FIELDS SUPPORTING DEVIATIONS FROM CLIMATOLOGY AS MUCH AS 30F!
WILL TEMPER THESE A BIT AND STICK WITH OUR TEENS TO 30S SCENARIO. MORE
ON THIS IN LATER FORECASTS.