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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KLWX 032152
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
452 PM EST MON MAR 3 2014

.SYNOPSIS...
LOW PRESSURE OVER SOUTH CAROLINA THIS AFTERNOON WILL MOVE OFFSHORE
THIS EVENING. COLD CANADIAN HIGH PRESSURE RETURNS TO THE AREA
TONIGHT THROUGH WEDNESDAY. LOW PRESSURE IS EXPECTED TO DEVELOP NEAR
THE SOUTHEAST COAST MIDWEEK AND TRACK UP OR JUST OFF THE EASTERN
SEABOARD LATE IN THE WEEK.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
-- Changed Discussion --
DRY AIR HAS BEEN PUNCHING SOUTHWARD INTO THE CWA AND THIS HAS
BEEN EATING AWAY AT THE SNOW. AS SUCH...HAVE BEEN TRIMMING THE
NORTHERN FRINGE OF THE WINTER STORM WARNINGS THIS AFTERNOON. JUST
ADDED ANOTHER ROW OR TWO OF WRNG CANCELLATIONS...FOLLOWING RADAR
TRENDS AND LTST HRRR.

DRIER AIR WILL CONTINUE TO SPREAD THROUGH THE CWA...WITH PARTIAL
CLEARING SETTLING IN THIS EVENING. HIGH PRESSURE RIDGE OVER THE
MIDWEST WILL ALSO EXPAND EASTWARD MAKING IT INTO THE MID-ATLANTIC
BY DAYBREAK TUESDAY.

TEMPERATURES ARE ALREADY IN THE TEENS ACROSS THE CWA THIS AFTERNOON
AND WILL ONLY FALL MORE TONIGHT. EXTENT OF CLEARING AND HOW MUCH
WINDS DIMINISH WILL DETERMINE HOW COLD IT WILL GET. MET/MAV GUIDANCE
EXHIBIT PRONOUNCED DIFFERENCES...WITH THE MAV QUITE A BIT LOWER THAN
THE MET. PREFER THE MAV GUIDANCE WITH FAIRLY HIGH CONFIDENCE IN
CLEARING TONIGHT. ALSO BELIEVE THAT WINDS WILL DIMINISH OVERNIGHT.
THESE ASPECTS COMBINED WITH A SNOW PACK SUPPORT THE COLDER SOLUTION.

DO NOT PLAN ON ISSUING A WIND CHILL ADVISORY ATTM...GIVEN THE
EXPECTATION OF DIMINISHING WINDS AS TEMPERATURES BOTTOM OUT.
OBVIOUSLY IF WINDS WIND UP BEING HIGHER THAN FORECAST OVERNIGHT THEN
THIS WOULD NEED TO BE A CONSIDERATION.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
SFC HIPRES CENTERED OVER THE NRN MID ATLANTIC REGION TUE MRNG WILL
WEAKEN TUE AFTN AND NGT AS IT PROGRESSES EWD TOWARD THE COAST.
AIRMASS WILL MODERATE THRUOUT THE PERIOD AS H8 RIDGE AXIS SHIFTS
EAST OF THE AREA AND WINDS START TO VEER MORE FROM THE SOUTH.
LEANED ON THE COLDER SIDE OF GUIDANCE FOR TEMPS GIVEN THE SNOW
COVER. FCST HIGHS IN THE UPPER 20S AND LOWER 30S TUE...AND LOWS IN
THE SINGLE DIGITS AND TEENS TUE NGT ARE BOTH 15-20 DEG BELOW
NORMAL.

A PAC NW SHORTWAVE TROUGH WILL AMPLIFY OVER THE CENTRAL PLAINS WED
AND SERN CONUS ON THU. 12Z MODELS CONTINUE TO INDICATE SFC LOPRES
DEVELOPMENT NEAR THE SOUTHEAST COAST. A SUPPRESSED TRACK OF THIS LOW
IS FAVORED UNDER A PREDOMINANTLY ZONAL FLOW PATTERN AND AN ABSENCE
OF PHASING JET STREAMS. MOST OF THE MODEL GUIDANCE PROGS THE TRACK
OF THE LOW FAR ENOUGH OFFSHORE AND SOUTH OF THE AREA TO KEEP THE
BULK OF THE PRECIP SHIELD DOWNSTREAM OF THE CWA ON THU. HAVE
CONFINED LOW CHANCE POPS FOR RA/SN ON THU TO FAR ERN AREAS OF THE
CWA. COMPARED TO TUE...TEMPS 5-10 DEG WARMER WED AND 10-15 DEG
WARMER ON THU ARE FCST.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LOW PRESSURE WILL DEEPEN OFF THE SOUTHEAST COAST THURSDAY NIGHT
BEFORE MAKING ITS WAY NORTHWARD OFF THE EAST COAST ON FRIDAY.
THIS GENERAL SYNOPTIC PATTERN OF A COASTAL LOW FORMING FOR THE END
OF THE WORKWEEK HAS PERSISTED IN THE GLOBAL MODELS THROUGH THE
PAST WEEKEND...THOUGH THE TRACK OF THE LOW AND THE RESULTING LOCAL
EFFECTS HAVE VARIED RUN-TO-RUN. BOTH EURO AND GFS CONTINUE TO
TREND THE LOW OFF THE COAST...SO LEFT ONLY CHANCE OF LIGHT SNOW IN
THE FCST FOR THURSDAY NIGHT/FRIDAY MORNING.

HIGH PRESSURE WILL WORK INTO THE AREA FOR THE END OF THE WORKWEEK
AND BEGINNING OF THE WEEKEND. WEAK LOW PRESSURE MAY FORM AS A
SHORTWAVE TROUGH PASSES OVER THE MID-ATLANTIC SATURDAY NIGHT AND
SUNDAY MORNING. THIS FEATURE IS AGREED ON IN BOTH THE GFS AND EURO.
WITH LOWS SATURDAY NIGHT AROUND FREEZING...PRECIP TYPE SHOULD BE
MOSTLY RAIN WITH LOW QPF EAST OF THE ALLEGANY FRONT. HIGH PRESSURE
SETTLES BACK INTO THE AREA FOR THE BEGINNING OF NEXT WORKWEEK.

&&

.AVIATION /22Z MONDAY THROUGH SATURDAY/...
SNOW HAS ENDED AT ALL TERMINALS EXCEPT CHO...WHICH SHOULD END BY
21-22Z. VFR CONDITIONS RETURN IN THE WAKE OF THE SNOW. NORTH WINDS
MAY GUST UP TO 20 KT THIS AFTERNOON...BUT WILL DIMINISH TONIGHT AS
HIGH PRESSURE BUILDS IN FROM THE WEST.

VFR TUE AND WED UNDER THE INFLUENCE OF HIPRES. THE LATEST GUIDANCE
KEEPS A COASTAL LOW WELL SOUTH AND EAST OF THE AREA THU. ANY WWD SHIFT
IN THE CURRENT GUIDANCE WOULD INCREASE THE RISK OF AT LEAST LGT RA
OR SN ON THU.

VFR CONDITIONS ARE EXPECTED LATE IN THE WEEK.

&&

.MARINE...
NORTH WINDS REMAIN IN SOLID SCA CRITERIA THIS AFTERNOON...BUT SHOULD
START TO DIMINISH THIS EVENING AS HIGH PRESSURE BEGINS TO BUILD IN
FROM THE WEST.

LGT WINDS UNDER THE INFLUENCE OF CANADIAN HIPRES ON TUE AND WED.
LOPRES IS EXPECTED TO DEVELOP OFF THE SOUTHEAST COAST MIDWEEK. THE
PRESSURE GRADIENT BETWEEN THIS LOW AND HIPRES TO OUR NORTH ON THU.
THERE IS A POSSIBILITY OF WINDS REACHING SCA CRITERIA ON
THU...ESPECIALLY IN THE MID CHSPK BAY AND LATER IN THE DAY.

A SMALL CRAFT ADVISORY MAY BE NECESSARY THURSDAY NIGHT AND FRIDAY AS
A LOW PASSES TO OUR EAST OFF THE COAST.

&&

.CLIMATE...
-- Changed Discussion --
IAD...
STORM TOTAL SNOWFALL REPORT TODAY FOR IAD WAS 4.9 INCHES...WHICH
TIES 3 MARCH 1978 FOR THE 8TH HIGHEST DAILY SNOWFALL IN MARCH
SINCE DULLES SNOWFALL RECORDS BEGAN IN 1962 AND THE MOST IN MARCH
SINCE 5.1 INCHES ON 2 MARCH 2009.

THE CURRENT FCST LOW TNGT FOR IAD IS 0F DEGREE...WHICH WOULD SET
THE DAILY MIN TEMP RECORD FOR 4 MARCH AND APPROACH THE ALL-TIME IAD
MIN TEMP RECORD FOR MARCH OF -1F DEGREES ON 15 MARCH 1993 (THE NIGHT
FOLLOWING THE MARCH 1993 SUPERSTORM).

DCA...
STORM TOTAL SNOWFALL REPORT TODAY FOR DCA WAS 3.8 INCHES...WHICH
TIES 22 MARCH 1914 FOR THE 32ND HIGHEST DAILY SNOWFALL IN MARCH
SINCE OFFICIAL WASHINGTON SNOWFALL RECORDS BEGAN IN 1885. IT WAS
ALSO THE MOST SNOWFALL IN A DAY FOR MARCH AT DCA AIRPORT SINCE 4.5
INCHES ON 2 MARCH 2009.

THE CURRENT FCST LOW TNGT FOR DCA IS 9F DEGREES. MIN TEMPS IN THE
SINGLE DIGITS IN MARCH HAVE ONLY OCCURRED TWO OTHER OCCASIONS ON
RECORD (6F DEGREES ON 5 MARCH 1972 AND 4F DEGREES ON 4 MARCH 1873).
OFFICIAL TEMPERATURE RECORDS FOR WASHINGTON DC GO BACK TO 1872.

BWI...
STORM TOTAL SNOWFALL REPORT TODAY FOR BWI WAS 3.8 INCHES...WHICH
TIES BOTH 10 MARCH 1934 AND 10 MARCH 1960 FOR THE 42ND HIGHEST
DAILY SNOWFALL IN MARCH SINCE OFFICIAL BALTIMORE SNOWFALL RECORDS
BEGAN IN 1892. IT WAS ALSO THE MOST SNOWFALL IN A DAY FOR MARCH AT
BWI AIRPORT SINCE 4.7 INCHES ON 2 MARCH 2009.

THE CURRENT FCST LOW TNGT FOR BWI IS 5F DEGREES...WHICH WOULD TIE
THE DAILY MIN TEMP RECORD FOR 4 MARCH AND THE ALL-TIME BALTIMORE MIN
TEMP RECORD FOR MARCH THAT WAS SET BACK IN 1873. OFFICIAL
TEMPERATURE RECORDS FOR BALTIMORE GO BACK TO 1873.
-- End Changed Discussion --
&&

.LWX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
DC...NONE.
MD...WINTER STORM WARNING UNTIL 9 PM EST THIS EVENING FOR
     MDZ016>018.
VA...WINTER STORM WARNING UNTIL 9 PM EST THIS EVENING FOR
     VAZ055>057.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ530-
     531-535-536-538-539.
     SMALL CRAFT ADVISORY UNTIL 6 AM EST TUESDAY FOR ANZ532>534-537-
     540>543.
-- End Changed Discussion --

&&

$$
SYNOPSIS...JRK
NEAR TERM...BPP/HTS
SHORT TERM...JRK
LONG TERM...CEB
AVIATION...JRK/BPP/CEB
MARINE...JRK/BPP/CEB
CLIMATE...JRK/HTS