Washington DC NWS statement

[arlwx]

I'm rooting for the ETA myself (more inland/quicker warmup) than the GFS that NWS favors, as it might cut down on the impending travel headache (the return from Philly). But timing of the warm air is everything.

My SWAG for my Arlington VA driveway:
The 1-3 inches of snow predawn to mid-morning, then the dreaded wintry mix and some rain by mid-afternoon (which may or may not be enough to wash the mess out of my driveway before I return).


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
434 AM EST FRI DEC 12 2003


(snip)
LONG TERM

SAT...COLD AIR DAMMING WEDGE IN PLACE AGAINST THE SLOPES OF THE
APPALACHIANS WHILE LOW PRES OVER SRN MS TRACKS SLOWLY NORTHEAST.
ENOUGH LIFT AND MOISTURE IN PLACE BY 18Z SAT TO WARRANT A SMALL
CHANCE POPS MAINLY OVER THE WRN AND SRN PART OF THE CWA. PRECIP TYPE
TO START AS -SN EVERYWHERE.

06Z SUN-18Z SUN...THIS IS WHERE THE BULK OF PRECIP OCCURS.
ISENTROPIC LIFT INCREASES ABV COLD DOME OF HIGH PRES. COUPLE OF
INCHES OF SNOW POSSIBLE BEFORE PRECIP BEGINS TO CHANGE OVER TO SLEET
AND/OR FREEZING RAIN. 00Z GFS BRINGS THE 1550M H8-H7 THICKNESS LINE
NORTH TO PETERSBURG AND DC SUGGESTING SUBSTANTIAL AMT OF WARM AIR
ALOFT TO CHANGE PRECIP OVER TO FRZA OR RAIN. BEST SN ACCUMULATIONS
POSSIBLY CLOSE OR GREATER THAN WARNING CRITERIA OVR THE FAR NWRN
COUNTIES WHERE GFS HOLDS TO COLDER AIR LONGER BUT EVEN THERE A MIX
TO SLEET POSSIBLE AS H8-H7 THICKNESS LINE CLIMBS OVR THE CRITICAL
VALUE OF 1540M BY 12Z SUN.

WRAP AROUND PRECIP SUN NIGHT AS LOW BEGINS TO DEPARTS. KEPT IT
SIMPLE HERE AS JUST A CHANCE OF RA/SN. BASED ON 00Z GFS EVENT IS
OVER BY 12Z MON. KEPT A LOW CHANCE OF PRECIP FOR THE FIRST HALF OF
MON AS THERE STILL SOME UNCERTAINTY. DID NOT MESS WITH FCST BEYOND
MON.

WILL CONTINUE WITH WINTER OUTLOOK AND LEFT DAYSHIFT DECIDE WHERE TO
GO WITH A WATCH. PTYPE FCST TOO COMPLICATED AND NOT ENOUGH
CONFIDENCE ATTM TO DECIDE WHERE WATCH WOULD BE NEEDED. BEST
POTENTIAL FOR THAT LOOKS TO BE THE FAR NWRN COUNTIES.

ROSA