A rather complex storm system may impact the area on Saturday (December 29, 2012) that could bring a mixed bag of precipitation, mostly in the form of rain. However, there is a chance of snow for the area, as noted in the current NWS forecast:
If this event pans out, this would be our first observation of snow for the season. It could also be our first chance for accumulating snow as well. More discussion about this event is detailed below in the NWS extended discussion:
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/…
WINDS WILL SLOWLY SUBSIDE THIS EVENING AS PRES GRADIENT
SLACKENS…ALTHOUGH WILL STAY BREEZY ON THE ERN SHORE THROUGH THE
EVENING. OTHERWISE…HIGH PRESSURE SLIDES OFF THE COAST BY LATER
FRI AND THE REGION WILL RESIDE UNDER A MOSTLY CLEAR SKY ONCE AGAIN
THU NIGHT AND FRIDAY. EARLY MORNING LOW TEMPS SHOULD BE COLDER FRI
MORNING WITH READINGS IN THE MID 20S TO MID 30S AND HIGHS NEAR
NORMAL IN THE UPPER 40S TO AROUND 50 FRI.THE NEXT LOW PRESSURE SYSTEM SLATED TO AFFECT THE MID ATLANTIC
STATES WILL BEGIN TO DEVELOP IN THE GULF COAST STATES FRI NIGHT
AND TRACK NE TWD THE REGION OVERNIGHT INTO EARLY SAT MORNING. MID-
UPPER LEVEL FLOW IS FAIRLY PROGRESSIVE INITIALLY SO THE SFC LOW
DOES NOT INTENSIFY THAT MUCH FRI NIGHT INTO SAT MORNING.
HOWEVER…OVERRUNNING PRECIP IS EXPECTED TO SPREAD ACROSS THE
REGION FROM SW TO NE EARLY SAT MORNING. WHILE THERE IS THE LACK OF A
COLD AIR WEDGE…TEMPS SHOULD HAVE NO PROBLEM FALLING NEAR
FREEZING BEFORE CLOUDS MOVE IN AND PREVENT THE ATMOSPHERE FROM
COOLING FURTHER. WITH THIS IN MIND…PRECIP MAY START AS ALL SNOW
IN FAR NW ZONES WITH A RAIN/SNOW TRANSITION ZONE TO ALL RAIN OVER
SE AREAS. IT DOES LOOK RATHER LIGHT INITIALLY SO ACCUMULATIONS
WOULD BE LIGHT. PRECIP IS EXPECTED TO BECOME ALL RAIN BY LATE
MORNING AS TEMPS WARM WELL ABOVE FREEZING…BUT HAVE GONE BELOW
GUIDANCE FOR HIGHS…MAINLY 40-45…UPR 40S TO LWR 50S FAR SE
VA/NE NC.THE CHALLENGING PART OF THE FCST COMES SAT NIGHT…HOW FAST DOES
COLDER AIR COME IN FROM THE NW AND HOW RAPIDLY DOES THE SFC LOW
INTENSIFY? NOTE THAT LATEST 00Z ECMWF SHOWS RAPID INTENSIFICATION
OF THE SFC LOW AND KEEPS IT CLOSER TO THE COAST DUE TO MORE
AMPLIFICATION OF THE UPPER TROUGH. THIS TRACK WOULD POTENTIALLY
LEAD TO SOME ACCUMULATING SNOW IN MAINLY NE PORTIONS OF THE CWA. GFS
IS WEAKER/SLOWER TO BRING IN COLD AIR…AND THE SFC LOW TRACKS
FARTHER OFF THE COAST W/ LITTLE MORE THAN A SMALL CHC FOR LIGHT
SNOW SHOWERS SAT EVENING/EARLY SUNDAY ACRS MAINLY THE ERN SHORE.
THE LATEST GFS ENSEMBLE SHOWS A LARGE SPREAD ON THE WEST SIDE OF
THE GFS TRACK SO THE ECMWF MAY BE ON TO SOMETHING…SO FCST WILL
TAKE THIS INTO ACCOUNT AND SIDE CLOSER TO THE COLDER SCENARIO.
GRIDDED FCST HAS CHANGEOVER BY 00Z NW…TO THE COAST BY
MIDNIGHT…WHICH IS FAIRLY CLOSE TO THE 1295 M 1000-850 THICKNESS
VALUES FROM THE ECMWF.