Eye still on fading hope Fri-Sat

The GFS model has trended closer to the region, and is tempting excitement, however, is still not close enough. The last three runs have been fairly close in developing the low east of Virginia and moving it northeastward and then northward about 500 miles east of Cape Cod and about 300 miles east of the 40/70 benchmark. 500mb forecasts indicates a second vort max off the Virginia coast but it swings east and weakens. The NAM has been consistent in bombing the low to sub 980, and in fact near 970mb. However also has trended more to the northeast, with a similar location to the GFS at 60hrs, but a larger eastward component after that.

Point forecast has kept 30% POPs through Saturday morning, but the zone forecast has dropped snow from the forecast, and there is increasing confidence of dry weather for the period. Our hopes for snow rest closer with possible CAA snow showers from an inverted trough on the northern jet. A better solution for snow overall would be a stronger system to the north, 1) to pull the coastal low further north and west, 2) for more moisture and better chance for snow development.

NWS AFD:

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
MODELS CONTINUE TO ADVERTISE COASTAL STORM DEVELOPMENT FRIDAY NIGHT
AND SATURDAY...BUT INSTEAD OF OCCURRING CLOSE TO THE COAST IT TAKES
PLACE EAST OF 70W. IN THAT POSITION...THE UPPER TROF AND ASSOCIATED
120 KT JET SERVE TO KICK THE STORM NORTH...BUT WIDE OF NEW ENGLAND
AND INSTEAD THREATENING NOVA SCOTIA AND NEWFOUNDLAND.

WE HAVE CONTINUED CHANCE POPS IN SOUTHERN NEW ENGLAND FRIDAY NIGHT
INTO SATURDAY. FIGURE THE UPPER TROF IS GOOD FOR AT LEAST SCATTERED
SHOWERS AS IT PASSES THROUGH. THE PRIME NUCLEATION ZONE ALOFT REMAINS
RATHER DRY DURING THE PERIOD...AND THE 1000-850 MB THICKNESSES REMAIN
BORDERLINE AT BEST FOR SNOW. THIS AUGERS POORLY FOR
PRECIPITATION...AND IF IT OCCURS IT WILL NOT BE FAVORABLE FOR SNOW.
BUT THE DEEPER LAYER IS COLD ENOUGH. A LOT OF QUESTION MARKS AND
MINUSES FOR SNOW...BUT CAN`T RULE OUT A PERIOD OF FLURRIES OR
SCATTERED VERY LIGHT SNOW DURING THE COLDEST PART OF THE NIGHT. SO
WILL GO WITH LOW CHANCE POPS FRIDAY NIGHT AND SATURDAY. THE BEST
CHANCE WILL BE THE CAPE AND ISLANDS WITH A LESSER CHANCE ALONG THE
MASS PIKE. WILL ALLOW FOR A CHANCE OF SNOW INLAND DURING THE
NIGHT...BUT CHANCE OF RAIN DURING THE DAY.

HPC Model Diagnostics discussion:

DEEP CYCLONE FORMING OFFSHORE THE EAST COAST FRIDAY WHICH LIFTS
NORTHEAST...
THE NAM HAS TRENDED NORTHEAST AND SOMEWHAT WEAKER WITH THIS SYSTEM
OVER ITS PAST DAY OF RUNS.  THE ECMWF IS ON THE NORTHEAST SIDE OF
ITS PAST COUPLE DAYS OF RUNS.  THE GFS HAS TRENDED DEEPER AND
CLOSER TO THE COAST OF NEW ENGLAND AND THE CANADIAN MARITIMES WITH
THIS SYSTEM OVER ITS PAST DAY OF RUNS.

DEEP CYCLONE FORMING OFFSHORE THE EAST COAST FRIDAY WHICH LIFTS
NORTHEAST....
AT THE SURFACE...THE MODELS ARE FAIRLY WELL-CLUSTERED IN THEIR
SURFACE SOLUTIONS WITH THE ECMWF/CANADIAN THE FARTHEST EAST.  WITH
THIS KIND OF AGREEMENT...A COMPROMISE OF THE AVAILABLE GUIDANCE IS
PREFERRED.  ALOFT...THERE ARE CLEAR DIFFERENCES AS THE NAM
DEVELOPS TWO 500 HPA CENTERS...AND THE ECMWF/UKMET/GFS SHOW A BIT
OF SPREAD CONCERNING THE POSITION OF THE 500 HPA CLOSED LOW WITH
THE CANADIAN SPLITTING THE DIFFERENCE.  MODEL TRENDS ARE MIXED
HERE.  THE UKMET IS IN THE MIDDLE OF THE SPREAD ALOFT...WHICH
APPEARS BEST AT THIS TIME.