MODELS SHIFT TOWARD MONDAY'S EAST COAST SYSTEM (BOSTON-DC METRO)
Posted: (November 22, 2008 03:36 pm)

We are now 48 hours from the Monday system along the East Coast and if you read my blogs you know this is the time when the model get much more accurate and I tend to play the NAM vs. GFS for weather systems this close. I do not discount the NGM, EURO, Candian and others, I just tend to lean more on the NAM/GFS solution. I do this from experience in the last 15 years of forecasting and the changes made with the NAM and GFS.

So where are we TRENDING. Many of you know that is a HOT WORD I use when forecasting because models are about trending not one model run. Often times a model may make a huge change on one run and go back and forth. Trust me I have been burned by that many times and use snow lovers go running for the TUMS when this happens. So what are the trends for the NAM and GFS. Let's look below and see where we are going. 

NAM RUN TODAY	7AM	THIS IS THE	LATEST RUN	TODAY
CITY	PRECIP	THICKNESS	5,500/850MB	SURFACE TEMP	MY CALL	NOTES AND TRENDING !
PHILLY	.31"	542 to 539	30-31	44 to 45	RAIN	WARMER TREND
LEHIGH VLY	.15"	536 TO 528	28 to 23	40 TO 32	RAIN TO FLURRIES	WARMER, LESS PRECIP
POCONOS	.16"	536-528	29 TO 23	37 TO 31	WET RN/SNW SHWRS	WARMER, LESS PRECIP
A.C. METR0	.65"	543 TO 531	32 TO 28	50 TO 42	RAIN	WARMER & WETTER
NYC METRO	.38"	541 TO 532	31 TO 27	45 TO 40	RAIN	WARMER & WETTER
BALTIMORE	.09"	543 TO 535	33 TO 28	44 TO 43	RAIN SHOWERS	WARMER, LESS PRECIP
D.C. METRO	.06"	544 TO 534	35 TO 28	45 TO 43	RAIN SHOWERS	WARMER, LESS PRECIP
BOSTON	1.29"	545 TO 536	32 TO 38	44 TO 49	HEAVY RAIN	WARMER & WETTER
GFS RUN TODAY	7AM	THIS IS THE	LATEST RUN	TODAY
CITY	PRECIP	THICKNESS	5,500/850MB	SURFACE TEMP	MY CALL	NOTES AND TRENDING !
PHILLY	.58"	543 to 524	33 to 20	44 to 35	RAIN	WETTER BUT COOLER THAN NAM
LEHIGH VLY	.72"	540 TO 526	31 TO 20	37 TO 21	RAIN TO SNW SHWRS	WETTER BUT COOLER THAN NAM
POCONOS	.75"	540 to 526	32 to 20	34 to 31	WET SNOW/3-5"	WETTER AND COLDER THAN NAM
A.C. METR0	.75"	545 TO 527	37 TO 22	51 TO 39	RAIN	WETTER, SLIGHT COOLER THAN NAM
NYC METRO	.93"	542 TO 525	35 TO 22	47 TO 36	RAIN	WETTER, SAME TEMPS AS NAM
BALTIMORE	.40"	544 TO 528	34 TO 23	44 TO 38	RAIN	WETTER, SAME TEMPS AS NAM
D.C. METRO	.36"	544 TO 527	35 TO 22	44 TO 37	RAIN	WETTER, SAME TEMPS AS NAM
BOSTON	1.04"	544 TO 537	34 TO 29	50 TO 42	OCC. HEAVY RAIN	SAME PRECIP, COOLER ENDING

MY THINKING AT THIS POINT...

This system is more typical of a November system than the last week or so. I do think the GFS has a colder ending and that has to be watched as the cold air comes down very quickly at 10,000 to 5,000 feet.  This could mean flurries in the end in the big I-95 cities, with snow showers in the Lehigh Valley.  The Poconos & Catskills could see a few inches of wet snow here ranging from 2-4" and maybe a little more if this all comes in perfect for them. Areas in the Lower Hudson Valley, NW NJ and Lehigh Valley could end as a period of SNOW SHOWERS.

THE "X" FACTORS ???

Well the models have been underplaying the cold this last week so could be a factor. The other is "snow pack" That may be a stretch since the Lake snow cover in PA, NY and Ohio is not widespread like a winter system and not all that deep. It's worth mentioning both factors but I lean heavily on that both factors WILL NOT 
have a huge impact on the Monday system.