National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KLWX 212137
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
537 PM EDT TUE MAY 21 2013

.SYNOPSIS...

-- Changed Discussion --
OFFSHORE HIGH PRESSURE WILL CONTINUE TO BRING WARM MOIST SOUTHERLY
AIR INTO THE REGION THROUGH THURSDAY. AFTERNOON AND EVENING
THUNDERSTORMS ARE POSSIBLE EACH DAY. A COLD FRONT WILL PASS
THROUGH THE REGION THURSDAY NIGHT INTO FRIDAY. COOLER CONDITIONS
ARE EXPECTED OVER THE WEEKEND.
-- End Changed Discussion --

&&

.NEAR TERM /TONIGHT/...

-- Changed Discussion --
ISOLD TSTMS PSBL OVR THE MTNS THRU MID EVE. THESE MAY PRODUCE
BRIEFLY HEAVY RAINS. UPR LVL WIND FIELD IS VERY LGT.

LGT FOG PSBL AFTR MDNGT...MOST PREVALENT RIGHT B4 SUNRISE AND THEN
QUICKLY BURNING OFF. LOWS IN THE 60S XCPT L70S IN THE CITIES.
-- End Changed Discussion --

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...

-- Changed Discussion --
CWFA WL BE WARM SECTOR THRU PD...AS SFC HIGH WELL OFF ERN SEABOARD
AIDS SLY FLOW/MOISTURE ADVECTION. THUS AMS WL REMAIN UNSTBL...W/
POPS GNLY INCREASING IN RESPONSE TO DROPPING MID LVL HGTS. WL STILL
HV A DIURNAL TREND TO STORMS. THU LOOKS TO BE THE BETTER DAY IN
TERMS OF TSRA DVLPMNT AS CDFNT/UPR LOW DROPS THRU GRTLKS. HV
RAISED POPS BOTH DAYS AND INTRODUCED LKLYS ON THU.

SPC HAS WRN MD/HIGHLANDS OUTLOOKED IN SLT RISK THU AHD OF THE CD
FNT.
-- End Changed Discussion --

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...

-- Changed Discussion --
CFP THU NGT. AFTR THAT THE NEXT SVRL DAYS LOOKING GOOD AS CANADIAN
HIGH PRESSURE BUILDS IN WITH TEMPS 5-10 DEGREES BELOW NORMAL.

SHORTWAVE OVER THE TN VLY ON SUNDAY SHOULD REMAIN WEST OF THE LWX
CWA...WILL HAVE TO MONITOR FOR INCREASED POPS. AS OF NOW EXPECT
SOME HIGH CLOUDS SUNDAY WITH A WARMING TREND STARTING THAT
CONTINUES INTO MID NEXT WEEK.
-- End Changed Discussion --

&&

.AVIATION /22Z TUESDAY THROUGH SUNDAY/...

-- Changed Discussion --
VFR CONDS AT ALL TERMINALS. XPCT AREAS OF LOW CLOUDS/FOG TO DVLP
LT TNGT...CONTG INTO THE WED MRNG PUSH BUT DISSIPATING AFTR
SUNRISE. THIS TIME HV LEANED MORE TWD FOG DVLPMNT INLAND SINCE
SKIES WL BE PRTLY CLR SUPPORTING RADL COOLING DOWN TO MOIST
DEWPTS. HWVR LOW CLDS WL BE LURKING JUST E OF DCA/BWI.

DIURNAL THUNDERSTORM ACTIVITY WED/THUR WITH IFR CONDS POSSIBLE IN
THE HEAVIEST ONES. SLY FLOW UNTIL A COLD FROPA THURSDAY NIGHT. NWLY
FLOW WITH CLEAR CONDS SATURDAY. JUST SOME HIGH CLOUDS ON SUNDAY.
-- End Changed Discussion --

&&

.MARINE...
THE PRESSURE GRADIENT WILL STRENGTHEN OVER THE REGION WED AFTN AND
NGT AS LOPRES MOVES THRU THE GREAT LAKES AND HIPRES REMAINS PARKED
OVER THE WRN ATLANTIC. SLY RETURN FLOW WILL INCREASE ACCORDINGLY
BETWEEN BOTH SYSTEMS. A SCA GOES IN EFFECT WED AFTN FOR THE WATERS
THAT ARE MOST PRONE TO SLY CHANNELING IN THE MID CHSPK BAY AND
LWR/MID TIDAL POTOMAC RVR. SCA EXPANDS WED NGT TO INCLUDE ALL OF THE
MD CHSPK BAY AS A SLY NOCTURNAL JET DEVELOPS.

SLY FLOW WITH HIGH PRESSURE OFFSHORE AHEAD OF A COLD FRONT THAT
COMES THROUGH THURSDAY NIGHT. SLY CHANNELING TO 20 KT POSSIBLE WED
EVENING...AND THURSDAY. NWLY FLOW TO 20 KT POSSIBLE FRIDAY. LIGHT
AND VARIABLE FLOW THIS WEEKEND.

&&

.TIDES/COASTAL FLOODING...

-- Changed Discussion --
EXPECT POSITIVE TIDAL ANOMALIES TO DEVELOP DURING THE MIDWEEK AS SLY
FLOW STRENGTHENS. CBOFS GUIDANCE...WHICH HAS VERIFIED FAIRLY WELL OF
LATE...FCST WATER LEVELS TO STAY BELOW MINOR COASTAL FLOODING
THRESHOLDS THRU AT LEAST THU MRNG.

COLD FRONT MOVES THRU ERY FRI MRNG. WLY WINDS BEHIND THE FRONT
SHOULD ERASE ANY POSITIVE TIDAL ANOMALIES.
-- End Changed Discussion --

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM WEDNESDAY TO 6 AM EDT THURSDAY
     FOR ANZ530-531-539.
     SMALL CRAFT ADVISORY FROM 2 PM WEDNESDAY TO 6 AM EDT THURSDAY
     FOR ANZ532>534-536-537-540>543.

&&

$$
UPDATE...WOODY!