[dT-REX]

SET CONDITION CHARLIE#43 .... SET CONDITION CHARLIE #4... issued
...........stardate 200901.29 at 02000z

WWCINC -- Weather Weenie Commander in Chief -- has issued CONDITION CHARLIE advisory#4 for a H.EC.L. --
HISTORIC EASTERN US LOW valid for the approximate time of 2 FEB 0700 EST to 5 FEB 0700 EST
for the Following areas .

CONDITION CHARLIE #5 covers the following areas

... THE OHIO VALLEY .... (IND OH western PA)
... THE EASTERN GREAT LAKES
... ALL of the APPALACHIAN MOUNTAINS ( far Northern GA eastern TN western NC far western VA ALL of WVA western half of NY state)
... Northern NEW ENGLAND


...There is a chance that this advisory will be Upgraded or Altered to H.O.V.S. (Historic Ohio valley Snowstorm)


CONDITION CHARLIE shall by declare whenever the atmospheric pattern and MODEL data shows a pattern that is FAVORABLE -- but NOT a probability-- of development of any of these features
S.E.C.S. (Significant East Coast Snowstorm) ...
M.E.C.S. (Major East Coast Snowstorm)...
H.E.C.S. (Historic East Coast Snowstorm) ...
S.E.C.L. (Significant Eastern US Low)...
M.E.C.L. (Major Eastern US Low)...
H.E.C.L. (Historic Eastern US Low)...

is likely to occur.


SITUATIONAL ANALYSIS :

There is a lot to say about this developing event for February 2-3 so let's get right to it. If one were to go back and take a look at the numerical model performance of the major winter weather events over the past 15 to 20 years (since the birth of modern numerical weather prediction models) one thing that stands out is that the major winter weather events have often been very well detected in the medium-range forecast. By that I mean to say such events as the January blizzard of 1996 the March 1993 super storm the December 2000 New York City New England snowstorm.. February 2006... Presidents' Day II February 16-17 2003 just to name a few of them... all very well predicted in the medium-range forecast period by the available medium-range weather model guidance. .

Even if you want to go back further in time the medium-range models had a stored breakthrough in the early forecasting of the severe New England blizzard of February 1978 as well as the Midwest Ohio Valley blizzard of January 1978 (aka the Cleveland superbomb) and the February 1983 I-95 historic snowstorm.

I believe we are looking at the same sort of thing here again. It is easy see what appears to be some similarities between two particularly historic events and the potential event for February 2 -- 3. The initial comparison that I and some other posters have made has to do with the similarity between the track and the surface intensity of this potential upcoming event in the March 12-13 1993 superstorm.

The March 1993 super storm featured a surface low pressure of 961 MB which occurred over the lower portion of the Chesapeake Bay. In March 93 superstorm is also noteworthy in that the massive intensification phase occurred when the surface Low was SOUTH of the VA / NC border. This is unusual in that most of the time the intensification phase occurs with Northeast snow storms and nor'easter's once the surface Low pressure area has reached the coast north of Cape Hatteras/ 35° north latitude.

The other comparison that some have made is based on the some similarity between FEB 2-3 upcoming event and the November 25 1950 great Appalachian blizzard. The massive snowstorm can be seen in the two-volume KU snowstorm books.



MARCH 1993 analog idea. There is validity to make a comparison beween that event and what will likely happen FEB 2-3. Unfortunately since so many people know of the March 1993 super storm it is clear that such a comparison IS going to be thrown around a lot between now and February 3 not only here but in a lot of other places. But there are some important differences which have to be taking the consideration.


Here is a map of the upper air pattern and service conditions for the March 1993 storm. Keeping in mind that it was mid-March... the first major difference to note is that 850 temperatures were a LOT colder in March 93 super storm than it will be February 2 -- 3.

 090129025341.gif (27.82K)
Number of downloads: 17



 090129025418.gif (28.31K)
Number of downloads: 11



In March 12 1993 NYC 850 temp was below -10c and the arctic air -- again for mid-March and not late January or early February!!!-- extended deep into the Tennessee Valley. Thus the baroclinic zone for the Southern low in the March 1993 storm was way to the south. The actual surface Low formed over the Gulf of Mexico in Florida Panhandle and under went explosive development there with hurricane force winds reported in the Florida Panhandle. This is one of the reasons why the southern Low developed so rapidly over the southeastern states which is not typical for the classic nor'easter or Northeast snowstorm

With the system for next week... the surface Map synoptic shows some key diffeences. First there will be a HIGH that will move off the East Coast which will set up southerly winds from Georgia to Maine ahead of the system.... so of course there will be no arctic air moving into place as the Low to the South develops. Indeed if anything the baroclinic zone will be well to the West of the East coast.

In addition as you can see from this map from 12 MARCH 1993 the phase between the streams occurred Over the Mississippi Valley where the northern branch finally caught up with the Southern short wave over the Delta. The powerful short wave developed a severe negative tilt over Alabama and Georgia were the surface Low under went explosive cyclogenesis.

With the February 2 -- 3 potential event for next week the models are clearly showing the phase occurring over the Mississippi Valley and just like in March 93.... the whole trough axis goes negative before it reaches Atlanta. The difference is that for February 2-3 event coming up.... it does NOT appear that the two streams are going to phase so deeply into the southeastern states. As a result the surface Low will NOT form over the Florida Panhandle and NOT undergo explosive development over the Florida Panhandle and Georgia.

Instead the surface Low forms over the Tennessee Valley and then tracks up the spine of the Appalachians or just to the east. Unless these models are vastly different there is little chance that this Low for February 2-3 in form over the Florida Panhandle and undergo explosive development over the Southeast states in a manner similar to the March 1993 super storm.


NOV 1950 : The first storm ever forecasted using NWS numerical model programs, brought heavy snow and hurricaneforce winds across 22 states. The storm killed 383 lives and caused $70 million in damages. This analog is probably a much better fit but it is not well known. In many ways the pattern was a somewhat similar to March 1993 but in the November 1950 storm the phase occurred much further to the north. A baroclinic conditions were vastly different from the March 1993 super storm and much closer to what we are going to see February 2-3

click on these links

http://greatlakes.sa...50_500_loop.gif

http://greatlakes.sa...50_850_loop.gif

http://greatlakes.sa...50_sfc_loop.gif



Uccellini and P. J. Kocin presentation can be seen seen here from 2004 http://ams.confex.co...paper_73168.htm




2 COULD THIS SYSTEM SHIFT TO THE COAST -- a la MARCH 1993 SUPER STORM?

I think this is very doubtful for number different reasons. The first reason is that it goes against a seasonal trend which by now most of us know features systems tracking further north and west with time as we get closer to the event. Could this particular storm boxes seasonal trend and actually shift back toward the coast? Sure it could put you have to find a reason for that to happen other than wishing for it.

Wishing is not a sound basis for making a Meteorological assessment ( hey thats sig worthy!!!).

Another reason is that we are now within the Day 6 time frame of this event and closing fast. IF this shift to the East Coast is going to happen it will have to happen soon.

In addition the other problems we have with reagrd to this system and weather models is that the Canadian the GFS and the UKMET all show significant biases to the south and east in this time frame... and this is obvious and self evident given how THOSE models were all consistently way too far south and east with the current Low pressure system now ending its trek for the Northeast. Last Friday Saturday and Sunday those models consistently forecasted below tracking through Northern Virginia and Maryland and providing a heavy all snow event from northern New Jersey into all of New England.

In addition even if the system were to shift to the coast because of the synoptic set up at the surface going into the event -- the big High movng off the East coast which is a terrible set up for East Coast snowstorms --the entire event would have to a phase in other two streams which are allow the Upper Low to close off and undergo undergo explosive cyclogenesis close enough to the coast to overcome the Low-level warming but just far enough off the coast so that they heavy comma head snows fall over the I-95 cities.

Talk about a miracle.

[/size]

Focusing on this next system for February 2 -- 3 you also need to be wary of surprise big changes which might occur within one model cycle... where the previous model runs had no such feature. In particular the 0z FRI operational GFS is a case in point. Over the last several runs this model has been depicting a closed transitory 500 low located somewhere off the southeast Canadian coast. However on the new 0z Wednesday in one of the GFS that closed 500 MB Low is now much stronger much deeper and sticks around over southeastern Canada or just off the Newfoundland coast for a prolonged period of time. The development of this Upper Low into a stationary feature near Newfoundland -- essentially making it a 50-50 low-- is a major change from what the ealier runs of the EFS for showing now suddenly for some reason this model has developed a weak insignificant Low pressure area in the West Atlantic into a massive system which stalls over just east of Newfoundland Canada -- making it a 50/50 Low.


3. NE US SNOWSTORMS DO NOT OCCUR BECAUSE THERE IS A LOW NEAR THE COAST ...
I've said this before and I am probably going to say it many times but apparently it needs a lot of repeating. When the models and not cause snowstorms. The big classic historic northeast Snowstorms occur only when certain conditions are current in the atmosphere before the event reaches the East Coast and begins to develop. Seeing a BIG L on a weather map that is within 500 miles of the East Coast between the months of December and March does not make it in East Coast snowstorm threat.

When the models are representative of what's going on in the atmosphere. It's not really useful to say "But these 3 models are futher south and east because while that hat might be true she doesn't have a real bearing on how the atmosphere is going to develop.

Case in point the European model from last Thursday and Friday. The models consistently taking the main low and its associated short wave through the Ohio Valley and consistently had the track does most furthest to the north and west along with the warmest 850 temperatures and the warmest low-level warming. And to be sure last Thursday and Friday and even Saturday the European model was by itself on the 0z and 12z runs. Yet by Saturday 12z runs many of the other models start to turn dramatically towards the European solution once we got within 72 hours... this is especially true with the UKMET and the Canadian. On January 23 the 0z and 12Z UKMET had the main low tracking off the southeast the new coast and burying most of the cities in the I-95 Carter from DC to Boston with a tremendous snowstorm. On January 24 at the Ukmet began to shift dramatically to the north and west so that by 12z the UKMET had the surface low tracking through WVA.


It is important that when you're comparing models you are comparing apples and oranges. Often time a lot of amateur weather hobbyists / enthusiasts will compare the current run of the European to that of the GFS or CMC or Ukmet. It's okay to do that to get a general idea of what's going on but more importantly at this stage of the game it is imperative that you compare the current run of a particular model with its previous editions of the SAME MODEL to find out what the trend is in that particular model.

In nother words compare the current run of the European to the previous few runs the European to find a what the trend on the European model has been. You do not get a trend by comparing the European to the GFS since a totally different models. By doing so you are comparing apples to dinosaurs. You can compare any operational model to its ensemble to see if it is an outlier or with the operational model solution is within the ensemble mean.

But again you have to compare ensemble means to the previous versions to see what the ensemble mean trend is. He does not do you a lot of good to compare the GFS ensemble to the Canadian ensemble.




SUMMARY:

as of right now... I do not see this event as a serious no threat at all to any portion of the I-95 cities... from RDU to BOS. In fact for those areas I see a lot of warm temperatures and showers and heavy thunderstorms. If one wishes to formulate a track similar to March 1993 but displaced it 100 miles or so to the West ... I could support such a idea/ forecast. This looks to me to be a heavy and possibly a historic snowstorm for much of western Virginia the far western mountains of North Carolina and Virginia perhaps eastern Tennessee Mountains Central and East Ohio much of western Pennsylvania and western New York State as well as the eastern Great Lakes.

[size=3]Once the system closes off in the atmosphere and achieves maximum intensification it should bring widespread heavy snows for much of upstate New York the St. Lawrence Valley and Northern New England.

[simpsonsbuff]

Dave, great write up as they always are. I do have a sorta IMBY question here. You say

Quote

Once the system closes off in the atmosphere and achieves maximum intensification it should bring widespread heavy snows for much of upstate New York the St. Lawrence Valley and Northern New England.

This sounds to me what you are saying is that the system will create its own cold air and change what was rain in NNE to snow. So that the areas that received 12+ today in W NH and into Vermont would see a rain to snow hit. A big storm, but not what you believe could be a historic storm to the places listed above?

Thanks!

[CAT5ANDREW]

Could NYC/LI be looking at a potential 3-4 inch within a 12 hour period rainstorm with high temps in the 50s with Thunderstorms??

AND.....Could THIS Low be the one to start the process towards a TRUE -NAO??

[stebo48858]

Nice write up, will be interesting to see the evolution of this system as it progresses through the weekend and into early next week, hoping maybe back up a little west more to include Detroit area, but I don't wanna go wish casting here, an interesting storm is still interesting even if it misses me by miles.

[nin9inch9nails]

Dave,

I predict 4,000 hits on thread by day's end. 3,000 coming from the folks living on the EC telling you why you're wrong. 1,000 telling you why you're correct... :whistle:

[MidwestChaser]

DT,

How far west do you think this'll end up?

[dT-REX]

nin9inch9nails, on Jan 29 2009, 01:05 AM, said:

Dave,

I predict 4,000 hits on thread by day's end. 3,000 coming from the folks living on the EC telling you why you're wrong. 1,000 telling you why you're correct... :whistle:

Yeah well as you know Hart I am one that caves into public opinion rather easily

[Hoosier]

New UKIE is jaw dropping.

[dT-REX]

CAT5ANDREW, on Jan 29 2009, 12:57 AM, said:

Could NYC/LI be looking at a potential 3-4 inch within a 12 hour period rainstorm with high temps in the 50s with Thunderstorms??

AND.....Could THIS Low be the one to start the process towards a TRUE -NAO??

This Low will help bring about a -NAO

and I see increased threat for a SECS MECS threat 11 -12 FEB 2009

I may issue CONDITION CHARLIE #5 Thursday Midday

[dT-REX]

Hoosierwxdude, on Jan 29 2009, 01:09 AM, said:

New UKIE is jaw dropping.

yeah I saw... I like that solution some

[LES_CHASER007]

Very good discussion DT and extremely informative.

[NCAPPS86]

SOUNDS GREAT DT!

[HM]

Hey DT, I agree w/ this and said the same things the last two days. This is NO way an East Coast potential and never was. But it certainly could be an historic event and one to tell the grandchildren for the interior regions.

***IF the streams phase/go severely negatively tilted, there could be a sub 975mb SLP moving across the Northeast***

Perhaps a FEB outbreak of severe weather for the East Coast/Southeast ahead of the SLP?

[VortMax]

This winter cannot end fast enough.

[simpsonsbuff]

simpsonsbuff, on Jan 29 2009, 12:55 AM, said:

Dave, great write up as they always are. I do have a sorta IMBY question here. You say This sounds to me what you are saying is that the system will create its own cold air and change what was rain in NNE to snow. So that the areas that received 12+ today in W NH and into Vermont would see a rain to snow hit. A big storm, but not what you believe could be a historic storm to the places listed above?

Thanks!

I'll take that as i'm reading it right, haha.

[nesis]

This storm will go into --

Volume III of the KU book --

in the section titled --

"Near Misses"

[weatherwiz]

HM, on Jan 29 2009, 01:18 AM, said:

Hey DT, I agree w/ this and said the same things the last two days. This is NO way an East Coast potential and never was. But it certainly could be an historic event and one to tell the grandchildren for the interior regions.

***IF the streams phase/go severely negatively tilted, there could be a sub 975mb SLP moving across the Northeast***

Perhaps a FEB outbreak of severe weather for the East Coast/Southeast ahead of the SLP?

I've been thinking about that. This looks like this could be a setup prime for those in the SE for this time of year. If they can generate enough instability to survive the incredible shear that will be in place there could be some nasty storms down that way. I would think lapse rates wouldn't be an issue either as the SLP begins to rapidly deepen drawing in colder air into the center. This should help strengthen the lift as well. Moisture return would be no issue either with such a strong flow out of the gulf they could easily advect quality moisture into those areas. Still about a week out but this potential is looking quite fun!

[nesis]

State College, PA was a sweet spot in 93 whereas Philly got it ok

In this case it looks like State College, PA will be the Philly of 1993. In the game but just not west enough.

[TeaysValleyWV]

I wonder if my kids will ever get to go back to school...4 days out this week so far, probably a few more next week. They will probably cancel just on the threat monday. I'm liking the track so far.

[HM]

weatherwiz, on Jan 29 2009, 01:23 AM, said:

I've been thinking about that. This looks like this could be a setup prime for those in the SE for this time of year. If they can generate enough instability to survive the incredible shear that will be in place there could be some nasty storms down that way. I would think lapse rates wouldn't be an issue either as the SLP begins to rapidly deepen drawing in colder air into the center. This should help strengthen the lift as well. Moisture return would be no issue either with such a strong flow out of the gulf they could easily advect quality moisture into those areas. Still about a week out but this potential is looking quite fun!

At first, when the streams are separate, there will be strong ascent in a jet couplet across most of the Gulf Coast/Southeast w/ an intensifying surface low. The trouble is, the baroclinic zone is not quite as pronounce YET like it will be later on in its life cycle. However, there could be some good theta-e advection for Florida/coastal plain of GA/SC/NC and as the jet lifts north and phasing happens.... a good right entrance jet region ascent for most of this area, especially FL.

At this point it is all speculation but could be a SOLID FEB styled Southeast US outbreak of severe weather. Depends on when exactly things phase and how much advection can occur.