Scott's Dec 2006 Blog

Mid-Atlantic Radar

Scott's December, 2006 Blog

New Year's Eve: Out With The Old, In With The Older.
Sunday, December 31

I am reminded of The Who's song "Won't Get Fooled Again": meet the new boss, same as the old boss.

Not much to add to the ideas that have been persistently presented here...mostly zonal flow + Southeast High Pressure Ridge (similar effect as a "Bermuda High") = no winter. And while the signs *seem* to be there that the pattern will evolve, only the calendar suggests a prolonged period of storm winter weather is pending.

SHORT TERM. The storm that produced snow and a moderate ice event across Colorado and the Plains (and severe wx near the Gulf Coast) is now pushing up into the Great Lakes. The attendant frontal boundary is moving east; opening the door for copious moisture to be transported up out of the Gulf and across the southeast and over the Mid-Atlantic. Rather predictable setup here: accumulating snow to the northwest behind the Low, storms and rain to the southeast along the Front. Rain totals exceeding one inch seem a cinch for the interior Southeast from Alabama up into Virginia...probably into PA and NY. Even the western Great Lakes will see rain from this event. In anticipation of this precipitation, numerous Flood Watches are in effect...click HERE for our Severe WeatherCenter.

Timing is not good for tonight's New Year's Eve festivities and travel, especially for the Mid-Atlantic and Northeast. While a "plain rain" event for most, pockets of freezing rain can not be ruled out for locations north of the PA Turnpike.

The storm will pinwheel a dry slot over the Mid-Atlantic effectively shutting down the precipitation by Monday night. Not much in the way of backlash precipitation, although the favored western slopes of the Appalachians should see a little white stuff late Monday.

LONG TERM: During hurricane season I ran out of unique and creative ways to say: nothing happening. Much the same this winter, at least so far. High Pressure builds back into the region next week and this will get thermometers again climbing to above normal readings. Let's go with mid week highs of 60° in Raleigh, 58° in Richmond and 55° in Washington, DC. Another storm develops near the TX/LA border over the Gulf on Wednesday, producing rain and storms (again) before getting precipitation into the Tennessee Valley, southeast and Mid-Atlantic on Friday. Departing return flow from the High over the Eastern US, will have maintained temperatures too warm for frozen precipitation, so this too looks to be another rainmaker.

It just doesn't look good for any cold air intrusion until at least January 10 and that may be short lived.

PARTLY PERSONAL: Last blog for 2006 and I'd be remiss in failing to thank you for visiting Mid-Atlantic WX.com this past year. Of the many, many blessings in my life, I count highly among them the friendships developed here at the web site. Have a happy...and a safe...New Year's and we'll see you in 2007!

New Year's Storm Wet...Not White For Eastern US.
Thursday, December 28

Not very much going on as High Pressure will hang on into the New Year's Eve weekend. Click HERE for map. Temps remain above normal in areas with clear sky and slightly above average where clouds have thickened. Next storm ejects out of the SW CONUS, crossing the central US and brings a slight chance of severe storms Friday and Saturday along the Gulf Coast, east of Big Bend. This storm will bring another round of snow to the central Rockies and Plains tonight into early Saturday.

Typical of the pattern we've experienced since October, the system will tack up into the Lakes, pulling a Cold Front across the eastern US later in the weekend. Ahead of the Front, warmer air from the Southwest will nudge up temps across much of east from Friday into Sunday morning. The front should get plain rain into the Mid-Atlantic by Sunday morning...with another good soaking on tap. Rain could be moderately heavy with totals approaching one inch or more. So, while New Year's Eve probably is dry in the region the same can't be said for Monday or Monday night. Cold Front is east of the region on Tuesday and with High Pressure building in behind the boundary there could be scatter snow showers on Tuesday.

Chilly, but near normal temperatures for the first week of 2007. I've both conversed with people and posted here at the blog that this pattern holds until January 3 (at least). Better make that January 5-6...although I don't see a Biblical Eastern US snow storm coming at that time, either. In fact, some models and NCEP's Extended Forecast Discussion each suggest the so called "Bermuda" High builds back over the region in a week. There is plenty more time for winter to pile up on us!

Tornadoes Rake Tampa/N FLA on Christmas...Heavy Rains Deluge Mid-Atlantic.
Monday, December 25

The squally line previously discussed as a possible threat for Florida materialized this today near Florida and across northern Florida. A tornado touched down in Pasco County near the Tampa Country Club. Several injuries reported with reports of 30 homes sustaining moderate damage...just off I-75. Storm reports HERE. Imagine enjoying Christmas morning and moments later your home is hit by a tornado.

This line of storms spun in as the storm headed inland...very close to how the models depicted the inland track. No severe reports elsewhere although there were four separate tornado watches from Florida up to the VA/NC border. Heavy rain is moving into the Northeast and much of the Mid-Atlantic will be precipitation free on Tuesday. Mountains of WV and perhaps the Alleghany Foothills and Blue Ridge will see some snow showers or flurries on Tuesday but accumulations are anticipated only along the western slopes of the Alleghany Mountains. Temps rebound later this week prior to another storm coming up on the persistent southern jet...this may impact the region later on Saturday. *Probably* rain but several days away and we'll see how the next event sets up. Unless we get a Cold Air Damming (CAD) setup wedged over central-western Virginia later this week, I remain bullish we have at least one more week before cold air and invade the eastern US.

Christmas Storm Now Organizing...Taking Aim On The East.
Sunday, December 24

Using the Gulf of Mexico satellite loop from our HurricaneCenter we can see the storm now beginning to crank up over the GOM. Click HERE. I'll note this storm will have a surprise or two as models continue to poorly handle the dynamics. Here's what the NAM and GFS now show for the storm's track as of 6Z this morning (click graphic for more maps):

Slight shift back to the west is noted, dashing hopes of those wanting snow who are located east of the storm track.

Moderate to heavy rain along the Gulf coast, Florida and SE US...very slight chance of severe weather right along the coast from the Outer Banks down to Jacksonville. Severe weather...possibly in the form of a squally line...over the Florida Peninsula. Do not be surprised to hear a rumble of thunder anywhere from Mobile up to NYC on Monday afternoon! I know, you want snow on Christmas and get thunder. Well, I think that's kinda cool!

Snow likely across the Tennessee Valley, WV, Ohio Valley and interior Northeast. It is possible Lake Effect Snow piles up the accumulation south of Lakes Erie and Ontario, while Upstate NY and interior VT, NH and the "upcountry" of Maine see moderate accumulations exceeding 4-6 inches.

I'll be back late this afternoon with another look at the 12Z models and update timing and type of precipitation. No matter how you slice it, Christmas is a rainy and breezy day for the entire Mid-Atlantic region. Please check back here at the blog and visit our Winter WeatherCenter and Severe StormCenter for the latest.

UPDATE: 6:30PM. No big changes to the coverage presented here. Plain rain overnight in the Deep South expanding into SE US. Think mountains from extreme NE GA up through the Allegheny foothills (eastern slopes) and Blue Ridge Mountains south of Staunton, VA may start as wet snow or sleet...possibly changing briefly to freezing rain with small accumulation possible. Even these areas will transition to rain during the Christmas day. Expect widespread rain totals exceeding one inch across most of the Mid-Atlantic.

Entire I-95 corridor and the I-81 north of Roanoke, VA will be all rain. Rain will end from SW to NE across the Mid-Atlantic as the dry slot pivots through. As the storm passes, back lash snow will develop along interior mountains, kicking in the Lake Effect Snow machine and accumulating on the western slopes of the Alleghenies as well as western-central PA, the Southern Tier and Upstate New York. Any rainfall will change to snow with totals exceeding 2-4 inches in areas highlighted above.

Next update tomorrow afternoon. Safe travels and Merry Christmas!

Christmas Storm Poised To Bring Wind, Rain And Snow...
Santa Will Need His Raincoat In The Mid-Atlantic.
Saturday, December 23

Very dense fog this morning across portions of the Mid-Atlantic resulted from 1+ inches of rain yesterday. Here's what my back yard looked like here in the Shenandoah Valley this morning around 7:15AM:

This morning's fog is burning off (the old adage is true: fog at seven, gone by eleven) and winds are swinging around out of the west, so the region will be breezy while drying out. Temperatures should climb well into the 50's and 60's by early afternoon. Nice weather for last minute shopping!

The storm has crossed the Great Lakes and is tracking into eastern Canada. High Pressure now building in behind the departing storm will drift to the East on Monday as the new storm (currently over AZ) previously discussed here gets moving over the northern GOM. This latest system comes inland along the north-central Gulf coast and will produce rain over the Deep South and Florida. Here's this morning's model map depicting the 6Z NAM and GFS:

I will note the 12Z runs seems to be shifting slightly east and we'll see if this is a flip-flop or a trend. If you're along the I-95 corridor and want snow...this is helpful but do not hold your breath. It does appear this storm will phase with northern stream energy and as the intensifying system reaches PA the winds may really be howling! The tough part is determining where the storm will track and how much cold air gets into the mix.

It is most likely the storm tracks near but west of the Appalachian Mountains, so this will be a rain event south of the Potomac River. HOWEVER...cold air may be entrenched along the mountains from GA up into NC and precip may start as wet snow with some mixed precip. I'm also concerned a slight Cold Air Damming (CAD) event sets up over Extreme SW VA and the eastern slopes of the Blue Ridge...perhaps into the New River, Roanoke and Shenandoah Valleys early Christmas morning. If so, some light snow or freezing rain may kick off the precipitation. If this happens, there will be a change to rain as temps climb into the 40's. Rain totals may exceed one inch over the Carolinas and Virginia by Monday night. This scenario often produces "back lash" snow in these areas so we'll monitor how the Low develops and see if there's potential for for a rain to snow change later Christmas night. In any event, all rain for the central and eastern Mid-Atlantic states.

A potent storm coming up the Tennessee Valley into PA can trigger significant Lake Effect Snows, so we'll watch for this potential as well.

As the storm tracks north a secondary Low should develop around the Delmarva and New Jersey. Snow lovers from central PA through Upstate NY may be treated to a late White Christmas as this storm could dump at least a couple inches over these areas by early Tuesday morning. If you're traveling from Christmas Eve through Tuesday, you'll want to keep updated on this evolving storm threat...visit our Winter StormCenter and check in here at the blog for updates.

I will be updating the blog throughout the holiday weekend and hope you'll check in for the latest on this pending event. Today is also my birthday; turning 51 is far less traumatic than turning 50. I remember a great quote from Joe Garagiola, the former catcher and baseball broadcaster: "how old would you be if you didn't know how old you were?". Whatever 51 is supposed to feel like, it doesn't with me!

UPDATE: 7:00PM. Here's this afternoon's 18Z model map for the NAM and GFS:

GFS has moved slightly to the east from this mornings 6Z run shown above. What the lines do not depict is intensity...the GFS is a little weaker with the storm as it crosses the Mid-Atlantic. The devil is in the details with this type of storm and we'll continue to watch and see if the deepening Low Pressure center indeed tracks just east of the Appalachians. Still concerned for some frozen mix for areas mentioned in today's earlier post (especially if the track gets more to the east). No reason to change the belief this is a cold rainy event south of the Mason-Dixon Line (again, with the possible exception of mountain areas already highlighted). Monday night-Tuesday morning Lake Effect Snow should be underway with the possibility of some accumulation reaching the western slopes of the Alleghenies. Elsewhere, no snow.

I'll be back Sunday afternoon with a Christmas Eve update.

Mid-Atlantic Snow Lovers Want Bing To Sing: "I'm Dreaming of a White Christmas" ...But Instead Will Hear Aerosmith: "Dream On"!
Friday, December 22

Late on today's post (7:25PM) as I started Christmas shopping today. This large storm (located over Missouri in yesterday's blog) is heading into the extreme western Great Lake states. Snow with some mixed precip currently over Wisconsin will expand to the U.P of Michigan overnight. Plain rain to dissipate tonight across the Southeast and Mid-Atlantic...while in the Northeast the rain continues tonight with some frozen precip mixed The Adirondacks and interior New England.

This storm clears out on Saturday with sunshine and milder temps across the Mid-Atlantic. Next storm crosses the NW Gulf and comes up and in over the north-central Gulf coast on Christmas. Looks like this tracks inland and a new Low spins up off NC, then tracking up the Northeast Coast on Tuesday. This will renew the rainy precip for the Mid-Atlantic on Christmas...however...there is a chance of FREEZING RAIN from the eastern slopes of the Blue ridge into WV early Monday! Anyone traveling Christmas morning along the I-81 corridor or west should be alert for the potential of freezing precipitation. Temperatures will quickly rebound on Monday, but lingering frozen precipitation may return at night as the storm pulls away. We need to watch this as there could be snow over interior Pennsylvania into New York State. More on this in tomorrow's blog.

So, for the Mid-Atlantic region, there may be some freezing rain on Christmas, especially close to higher inland elevations but those of you dreaming of a White Christmas can (to mix metaphors) stick a fork in it. Ain't gonna happen.

Weather calms down for a couple days before attention will focus on another potential system racing on the Southern Jet Stream later next week.

While we are seeing a shift in the pattern, what is missing is cold air. And I am bullish that the cold stays bottled up in Canada at least through the New Year's weekend.

I'll be back tomorrow (my birthday!) with another update.

"Yes, Virginia, There Is A Pattern Change"...But...
Thursday, December 21

A quick look at Water Vapor shows a great deal:

You can see the "swirl" over the central Plains, depicting Low Pressure that dumped huge snow amounts with blizzard conditions over Colorado. The frontal boundary is easily seen with clouds, rain and some storms while drier air builds in over Texas. The Southeast and Mid-Atlantic will see rain overspreading the region overnight and Friday as the Low heads up into the Lakes. Right now, it looks like the Western Lakes and Northern PA/Southern tier of NYS will be the areas to watch for frozen precip on Friday morning. Cloudy and rainy all day event for the Mid-Atlantic with rain totals possibly exceeding one inch from NYC to Atlanta...heavier amounts for interior Carolinas. Click HERE for maps.

The Cold Front will traverse the region on Saturday and should be off shore by Saturday afternoon. Winds shift out of the W/NW but temps will only drop a few degrees behind the boundary. Sunday should be clear and mild for much of the region...in fact, temps could be 10-12 degrees above normal. This is when things become rather complicated!

A steady stream of storms should begin this weekend with the first forecast to develop south of TX/LA over the NW Gulf of Mexico. Computer guidance indicates this Low will track into the Ohio Valley on Christmas and I think that will verify. However, a new (secondary) Low Pressure area will also organize off the NC/VA coast, and this is when things get dicey. Mild air will be pumped into the Southeast and Mid-Atlantic by the first storm coming out of the GOM, therefore the Christmas Eve and Christmas Day forecasts feature rain and not snow. Right now I'm uncertain how potent the new coastal Low will become; the GFS model is honking BIG storm (read: snowstorm) for interior PA, NY and New England. It however, appears to be the outlier as most models show this to be a weaker system. This Christmas coastal storm will need to intensify in order to have any hopes of getting colder air down into the Poconos and Catskills. If this does pan out, this *could* be a significant interior snow storm north of the Potomac River. South of the Mason-Dixon Line, more rain on Tuesday with the specter of a little frozen precip along the mountains. I'm "iffy" about how this will develop but there is a shot of relief for snow starved folks in the Northeast.

So, yes, the pattern is showing signs of changing but the Southern Jet Stream is still ripping across the US and truly cold air remains trapped well to the north. Additional impulses will race along the southern jet next week and we'll watch the northern jet for signs of a shift into the US. I'm not enthused about any cold weather ideas until after January 1st but there are signs (NAO and PNA among them) that the pattern shift is underway and the colder air will eventually follow.

I'll be back with another post here at the blog on Friday night and will update throughout the weekend.

Winter Lovers in Near Panic! and...
Aurora Alert For Tonight.
Saturday, December 16

Near record warmth expands on Sunday and Monday over much of the Eastern US...prompting snow lovers to begin chugging Mylanta! How about mid 70's over the Carolinas and near 70's for the Mid-Atlantic?

Here's the dastardly doer of Fall's return:

High Pressure will drop down over the Southeastern US, pumping mild air from the Southwest. A wimpy, moisture starved Cold Front situated over the Central US will push east, banging into the Ridge. This boundary should cross the Mid-Atlantic late Monday. Not much in the way of rain associated with the frontal boundary, but it begin to change the current pattern. Behind the front, cooler High Pressure builds on Wednesday with temps getting closer to December norms...but not what most would consider cold. I will caution those who love wild winter weather that when this Ridging (similar in nature to a Bermuda High) is a dominant feature, snow storms are tough to come by in the Mid-Atlantic.

Next system to monitor will be a developing Upper Level Low (ULL) over the SW United States. This is the potential event hinted at in the December 14 blog. Where this tracks will have a huge impact on sensible weather over the Central and Eastern US as we approach the Christmas holiday weekend. My opinion is virtually every medium-range model is worthless with ULLs so I can't offer much commentary about how they depict this storm. When there has been a subtropical High over the SE US the trend for these systems is to track across the Lower Mississippi and then Ohio Valley. If this Ridge were to collapse or shift well offshore, a Carolina track would be favored. HUGE weather difference with those scenarios, so we'll watch and wait. Meanwhile, enjoy the great weather (sorry winter lovers...I find this flavor of winter to be exhilarating!).

AURORA ALERT. A coronal mass ejection (CME) is expected to near-miss Earth tonight. If you're a sky watcher, it may be worthwhile for you to "keep looking up" tonight!

Lastly, No blog yesterday so I'll extend belated best wishes during the Festival of Lights, which began at Sundown yesterday. Happy Hanukkah.

Mild, Not Wild, At Least For A While.
Thursday, December 14

I've talked with several people this week wondering where's winter? While it is mild this week, temperatures just one week ago were 15 to 20 degrees *below* normal. Using our wx station's data, the mean temperature for December, 2006 thus far is 34.6°; the typical mean temperature for December is 36.2°, so one can make the case (at least in my location) that December has been colder than normal. Of course, over half the month remains so we should examine what has transpired and where we may be going.

The next question I'm getting is "why the warm weather?". That's more complicated and I won't pretend to have all the answers. There is general agreement that an expanding El Nino tamped down the Atlantic hurricane season forecast numbers and this climate feature certainly has some impact on winter in the Southeast and Mid-Atlantic. We'll need to wait and watch to see if the extended pattern actually takes on El Nino characteristics...right not it is not. This graphic shows how NOAA is reading the current El Nino phase:

So far, so good. Again, this does not say it will always be warm in Alaska or normal in Florida...but it does show you the anticipated averages from December to February. What we like to watch for is fluctuations in the two jet streams (Polar to the north, Pacific to the south). To oversimplify, it is difficult to get cold and snow deep into the CONUS when the Polar jet is "trapped" in Canada and the Pacific jet is racing across the lower US. This pattern shifts when there's a change someplace else (High Pressure over the NW US, a "block" over the North Atlantic, changes in the SE "Bermuda" High). Until then, what you see is what you get.

If you look at the jet streams on the map above, you'll see the blue lines do not meet...not good for storm production! This split flow keeps temps mild for much of the CONUS. The two jet streams buckle when the pattern changes and sometimes they meet (phase) to produce drastic changes in weather and often generate potent storms.

Again, I'm grossly simplifying the processes at work to give you a basic idea of the current weather pattern. So, what's next? I believe we stay in a split flow for another week and then we see if change is in the wind. Some computer models are hinting the Polar jet drops closer to the Great Lakes and High Pressure Ridging off the SE US pumps back up well inland. Cold air in the north meets moisture transported across the south...perhaps up into the Mississippi and Ohio Valleys...hmm...inland storm on the first day of winter? I don't know. I am bullish on the current pattern through December 20 but beyond then, we'll watch and see.

Wondering what the average likelihood is for a White Christmas where you live? Click HERE.

Next update here at the blog on Saturday morning.

Weather In The East Is Weather In The Least
Monday, December 11

We remain high and dry here in the Mid-Atlantic and much of the Eastern US. High Pressure will hold firm over the Southeast/Mid-Atlantic, drawing above normal temps up on a southwesterly wind flow. A trof over the Central US will bring rain and some storms from Louisiana up into the Central Great Lakes on Tuesday, but dry High Pressure Ridging over the East will limit most of the precipitation east of the Alleghenies.

Meanwhile, a (sorta) Alberta Clipper will scoot across Canada. Atypical of most clippers that come down across the Lakes and produce snow, followed by colder air, this system will remain in the Great White North. In fact, both systems show up nicely on this morning's model map of the GFS and the NAM (click map for more models):

The GFS may be too far north but has the right idea and this Canadian system will not track south into the United States. It won't be all blue skies in the region as a Cold Front will cross the area late Wednesday, bringing rain to the Northeast and Mid-Atlantic States. South of the Potomac, there's not alot of moisture associated with this front and temps will be sufficient for plain rain (though areas from the tip of NYS to Aroostook County, Maine may see a mix or snow. This rather benign front will pass and air flow again becomes zonal with west to east winds as the weekend approaches. I don't think this is a long term deal...in fact, such a wind flow would beat back the High Pressure Ridging over the East...opening the door for a more active weather pattern the week before Christmas. Till then, the mild (and rather boring) weather hold across much of the Eastern US.

Next post here at the blog on Thursday.

Follow The Bouncing Thermometer
Saturday, December 9

Quick blog as the local High School my kids attend is in the State Championship football game today and I'll soon depart for the gridiron!

Boy, it was cold this morning. I took this picture with my cell phone at the top of my street this morning around 6:45AM:

Way too cold (and early) for me, but sunrise over the Blue Ridge Mountains is glorious!

The arctic blast has been brutal with about half of Deep South states setting new record lows for December 8. Today's low was 9 degrees at our Lexington, VA weather station and approached the year's lowest reading of 8.8° recorded on February 19th. Regional temps have been about 20° below normal!

Thursday's Cold Front ushered in arctic High Pressure that has chilled us to the bone, however, that Ridge is moving slightly east to hover over the SE US coast. Our Sea Level Pressure (barometer) was a very high 30.48" early this morning...if you check our wx station over the weekend you'll see the pressure slowly begin to drop as the High moves east. Remembering High Pressure rotates clockwise, the eastern US will be on the back side of the Ridge, meaning winds will shift more to the South and Southwest. Warmer air will build in and temps will bounce back up above normal on Sunday! Quick glance at this morning's sounding shows warmer air just above the surface and this will slowly mix down over the next two days.

Typical of winter Highs, this air mass is bone dry with Dew Points in the teens. When Relative Humidity drops below 50% one must be careful patting the dog or cat as mini-lightning (static discharge) is often the result. This dry and milder weather will hold for several days, foiling the hopes of winter weather lovers! While I certainly am not a model hugger, I will note the GFS continues bringing gloom and doom to those who can't wait for winter in the Mid-Atlantic. Near to above average temps with a front coming through Wednesday...producing wet not white stuff. From frozen pipes to Bermuda shorts? Welcome to early December in the Mid-Atlantic!

I'll be back on Monday with another post. Have a great weekend!

Feels Like Winter. :(
Wednesday, December 6

If you visit any of the weather boards you'll see legions of folks who live for winter. Not me. I lived in NY and moved to Virginia from Portland, Maine...I love both places but detest winter. So, the season's coldest air mass and the specter of white stuff in the region doesn't put me in a good mood! However, I know many who visit the web site can't wait for the cold and snow, so I'll put a good spin on things!

The brutal cold air over the Upper Plains continues migrating south and east. This Cold Front means business and will plunge temps well below normal across the Lakes down to the Gulf Coast.

The frontal boundary will push east on Thursday and produce gusty winds but not much in the way of precipitation for the Mid-Atlantic. Notable exception is WV and the NW slopes of the Appalachians where upslope snow showers probably gets squeezed out and produce some accumulations. There's a chance some light snow showers survive the trip over the mountains and track east over the northern Blue Ridge, NOVA and Maryland...but I'm not expecting accumulations in these locations.

Very cold air then sinks over the region Thursday night and Friday...temps easily will be 10°-15° below normal. Chilly, but, dry High Pressure for the weekend and early next week for the Mid-Atlantic area. Looks like a storm comes up out of the Central US later next week.

Sorry for missing yesterday's post as I was away from the computers all day. I'll be back Saturday morning, sooner if anything changes with the upcoming system.

Tomorrow is what used to be referred to as "Pearl Harbor Day". As a youth, I knew several people who where there on December 7, 1941; today just two of those are still us. My father (who happily is quite alive and well at the age of 85) enlisted in the US Coast Guard on December 8, 1941. These men and women all remain very special. It is appropriate to recall their service by visiting the National Parks Service Arizona Memorial at Pearl Harbor.

Coastal Clipper Mon-Tue, Cold Continues...And...
ly discussed here, Low Pressure will organize today off South Carolina and produce showers and rain along the southeast coast, then spread up over eastern VA and the Delmarva Peninsula this evening. Think this morning's models have a good handle on the storm track (click graphic for more maps):

The 12Z models are coming in as this is written and appear a tad east, meaning there may be less precip along the coast and inland. It remains possible that Philly will see some snow with this storm as it tracks northeast and out to sea. No snow, but some rain for Virginia. The track show above with the 6Z models brings some white stuff to NJ, Metro NYC and mostly rain to Long Island and Cape Cod. SE New England (except the Cape) could see small accumulations of snow overnight and Monday morning.

I'm keeping an eye on what should become an active Southern Jet Stream (shades of last winter???) and a storm threat later in the week...Thursday evening into Saturday. This may bring rain and storms to the north central Gulf Coast and Southeast before a rain or snow even in the Mid-Atlantic. Between now and then slightly below normal temps will rule the roost.

Our Winter StormCenter is ready for action...please visit for current information. I'll be back on Tuesday with another post here at the blog.

Damaging Storm Event Today With Strong Winds and Isolated Tornadoes.
Friday, December 1

Rather odd to begin December with near record warmth, Severe Thunderstorm and Tornado Watches, all brought to you be this most impressive storm system. Red MODERATE Risk box depicts where the strongest winds are likely to occur today:

Low Pressure will move up through the Ohio Valley and swing the Cold Front across the Mid-Atlantic and Northeast later today. Severe weather is enhanced by a "negatively-tilted" trof meaning the trof is tilted horizontally from the Northwest down to the Southeast (backwards from most trofs). This anomaly shows up nicely on the current 700mb RUC map...click HERE. Frequently this feature pushes cold air above warmer air at the surface but since colder air sinks, instability is the result. Vertical wind shear usually is observed as well. Given the very strong winds associated with the trof any thunderstorms that pop up today will be capable of damaging downbursts of 60+ MPH. The vertical wind shear could help some storms rotate and so tornadoes are possible, especially in the red MODERATE risk area. Straight line winds will be far more prevalent than tornadoes, sustained winds exceeding 30MPH likely from central North Carolina to western New England. Strongest storms to affect PA from 11AM-4PM...moving east to NJ late afternoon.

Also need to mention expansive Flood Watches in effect as the rain will become heavy in the northern Mid-Atlantic into Upstate NY.

Winds quickly shift to the W/NW once the front passes and these winds may be stronger and more damaging across the Virginias and Delmarva overnight tonight. Temperatures will plunge overnight and strong winds will make it feel even colder.

Please monitor your local forecast (just type your zip code in the Instant WX box above) and keep an eye on developments at our Severe WeatherCenter. You can get live real-time weather conditions from our wx station here in Lexington, Virginia by clicking HERE.

As we're in a short fuse weather situation, only a brief comment on the extended. Low Pressure forms off NC on Monday, but is expected to quickly track NE and away from the coast. This system will pump in another shot of cold air early next week and perhaps some precip from Philly to Long Island. Looks like another storm is looming in one week, but attention is focused on today's weather event.

Another quick update this afternoon.

UPDATE: 1:35PM. Severe threat virtually over for most of VA but eastern sections of VA and NE NC could see some storms with rain as sunshine is heating up things in the lower levels. East of Raleigh up to Norfolk storms may refire this afternoon. Props to SPC for nailing where the severe weather was forecast to develop! This morning's pre-frontal squall has fallen apart and now there are clusters of storms racing across PA, western NY and the Southern Tier. It is possible Supercell development will spin down isolated tornadoes...something to keep an eye on this afternoon. Already a couple tornado warnings east of PIT.

Today's storm reports (click map for more details):

Very strong and potentially damaging winds continue to be the main threat from this event. As the front crosses the region winds will quickly shift to the W/NW and further increase tonight. If you're interested in seeing how fast the low level jet stream is moving, take a look at the clouds...they're screeeeaming by!

I have one of those holiday Galas to attend this evening but will update again later tonight.

UPDATE: 11:20PM. Cold Front now moving off the coast with chilly and dry air filling in behind the boundary. It appears all wind and flood watches and advisories will be allowed to expire.

I'd like to share some graphics illustrating some of what we talk about here and what you might see on TV. Shortly before 3:30PM this afternoon, the Cold Front was crossing the Mid-Atlantic and interior Northeast. In fact, this graphic shows the Cold Front at the precise time it was crossing the Mid-Atlantic WX.com weather station:

You'll often hear comments about the pressure rising behind a front; this graph from our weather station shows SLP bottom out as the frontal boundary approaches:

Notice when the pressure begins rising...at 3:30PM...as soon as the front crosses the weather station. You can tell when a frontal boundary passes by simply observing a barometer; when it begins rising you'll know the front just passed your location.

Another tool is wind speed. Here's this afternoon's wind speed and gust graph:

The strongest winds were recorded as the front crossed the location of our anemometer. You can determine the same information without instruments...strong winds typically precede a shift in wind direction and when you observe this you'll know you now are on the back side of the boundary.

Most all of us are on the now behind the front and so goes the balmy temperatures of the past several days. Saturday should be slightly below normal for the region and then we'll contend with days of below normal temps.

I need to clean up the yard on Saturday and will have another post on Sunday to examine the upcoming coastal Low...and trouble in one week with the potential to bring a winter storm!

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