Possible cyclogenesis or bombogenesis situation next week.

[WXBUFFJIM]

Good evening everyone. As we establish a pattern change across the nation, a deep trough in the upper levels will likely establish itself along the eastern seaboard by later this upcoming weekend as cold air reinforces itself. In addition, keep an eye on a strong vigorous piece of upper level energy rolling past the Ohio Valley and into West Virginia and Virginia by Sunday night into Monday morning. By later Monday, this piece of upper energyand weak surface low pressure is forecast to transfer it's energy towards the Mid Atlantic coast resulting in strong cyclogenesis and possibly bombogenesis. By Monday afternoon, a 980 mb storm is forecast to develop off the Mid Atlantic coast. This combined with approaching upper level energy along the Mid Atlantic coast could potentially result in snow and enhanced accumulating snowfall rates and tremendous wind with gusts well over gale force from Virginia Beach northward up to Washington, Baltimore, Philadelphia, and New York City. With cold air in place and a reinforcing shot of cold air coming in during this snow, precip type shouls remain all snow in the major cities and mostly snow along the coastal areas with possibly rain to start along the Virginia and Maryland coast Monday and Monday evening.

By Tuesday morning, low pressure is expected to continue to intensify and is progged to be at 968 mb Tuesday afternoon near Cape Cod. Once again the Cape and eastern Long Island and Martha's Vienyard could see precip starting as rain or a rain/snow mix before becoming all snow. It appears snow, heavy at times could also occur from Providence northeastward into Boston by Tuesday. This combined with wind gusts of 40-60 mph potentially could result in near whiteout conditions.

While this scenario is not an absolute guarantee, forecast confidence is increasing for an ocean storm and a deepening upper trough along the northeast and Middle Atlantic coast from late Sunday-Tuesday. This makes for a potential winter storm situation for the major cities and even in coastal sections. As we go along day by day will continue to monitor this situation and folks living from Virginia northward up to New England are urged to monitor this situation closely.

Jim

[rainstorm]

thanks for the info

[Scorpion]

Sounds exciting for you guys in the Northeast!

[WXBUFFJIM]

It's something to watch, but it's not guarnateed the northeast and Mid Atlantic will se a snowstorm and wind combination because there is no indication of a greenland blocking high, which favors a winter storm of significant proportion. It's rare to experience a snowstorm courtesy of a coastal storm in the northeast and mid atlantic unless the Greenland blocking high is better established. Also the North Atlantic Oscillation I heard is positive at this point. While these scenarios favor a more offshore track, the major cities and coastal sections could still see their first real snowstorm of the season and while chances are low, it's not impossible. Agin though it's still too early to tell how much snow or wind if any does in fact occur since we're 5-6 days out here.

Jim

[PurdueWx80]

As a side note, in my synoptic dynamics graduate course last year, we talked a bit about blocking highs. Typically they are preceded by bombogenesis - it's sort of the same scenario as tropical systems that pump heat into a ridge. I don't think the Greenland block you mention is always necessary, and in fact, it would be interesting to see if the block develops 3-7 days after this storm. If so, that would guarantee the development of the polar vortex over southern CA or the US Christmas week or points after!

[Guest]

Looks increasingly likely Northern MA and NE will see snow, significant snow at that. Philly to Richmond is the question mark, but I think we will see a good snow (not as much as whats going on in NYC tho). Looks to be another snowstorm threat around Christmas for BWI South. Winter is definitly here!

[bostonweatherman]

Looks like a big one, based on the GFS 18z (after significant snows in the 6z and 12z) and the 0z and 12z ECMWF, at least for the Boston area.

http://www.geocities.com/bostonwinterwe ... ssion.html

[yoda]

Looks like a big one, based on the GFS 18z (after significant snows in the 6z and 12z) and the 0z and 12z ECMWF, at least for the Boston area.

http://www.geocities.com/bostonwinterwe ... ssion.html

I would not bite on that 18z GFS until I see the 0z GFS...

[bostonweatherman]

the fact is it continues a trend of several runs in a row... don't bite on a 6 or 18z when it's the first or second time showing the storm, but this is the fourth or fifth run in a row!

[wxguy25]

Sorry to spoil your fun, but I DONT see it this way at all.

I would be more concerned about the follow-up s/w on D7. that WILL have the potential to dig if the first system on D5-6 lifts Northeastward to Newfoundland and becomes the 50-50 low. That would force the secondary s/w to dig instead of cut across the lakes.

Furthermore, that energy should remain in one piece instead of having several different pieces of s/w energy consolidating into one as the phasing s/w digs into the lakes and closes off developing the primary SLP area (inducing bomb cyclogenesis); so the potential is BETTER w/ the follow-up system than the first one IMO. Even if the 50-50 is transient.

The new D 10 ECMWF is VERY …VERY promising w/ the Ridge up in Asia, it allows the Trough to amplify into Europe. that combined w/ the trough over the EUS could allow the ridge near the Azores (AZORES HIGH) to amplify toward Greenland sending the NAO negative, but we need to get the PV out of there first before this can happen.

[Dave C]

Local mets starting to discuss this potential. The next two days will see our coldest weather of the season(highs near 30 overnite lows in teens), then a 2 day warm-up Thurs and Fir followed by another cold shot this weekend. The storm potential is 5 days out so will be fun to watch model evolution as we draw closer to the event. Water temps still mid 40s east of Mass. so could make a very interesting rain-snow line forecast in SE Mass(if this thing verifies).

[bostonweatherman]

I see you're from Middleboro... could be very interesting for you...

I'm up in Newton, so it looks to be all snow here!

[yoda]

Local mets starting to discuss this potential. The next two days will see our coldest weather of the season(highs near 30 overnite lows in teens), then a 2 day warm-up Thurs and Fir followed by another cold shot this weekend. The storm potential is 5 days out so will be fun to watch model evolution as we draw closer to the event. Water temps still mid 40s east of Mass. so could make a very interesting rain-snow line forecast in SE Mass(if this thing verifies).

Topper Shutt (Channel 9 Met) here talking about POTENTIAL... and keeps stressing that it is POSSIBLE and we need to watch closely...

[Dave C]

Agree 100% Yoda.

[Stephanie]

Wow! This was only a mere possibility or a blip on the radar screen a few days ago.

Very interesting Jim. You always provide us with great summaries.

[fjf31970]

How would the weather on Long Island be if this storm does materialize?Could this be similiar to the dec 1992 storm?

[Chris the Weather Man]

How would the weather on Long Island be if this storm does materialize?Could this be similiar to the dec 1992 storm?

Ah, Dec 1992, but I think that this potential will be a FAR CRY from the Dec 1992....... heck, I think it can be wiscasting, but I could be wrong...

[nystate]

Not trying to be a "weenie", but is there any chance that Upstate NY (ART, SYR) could get in on some of the action?

[bostonweatherman]

maybe some... but not like the coast...