FXUS61 KLWX 200110
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
910 PM EDT SUN MAY 19 2013

.SYNOPSIS...
A WARM FRONT WILL SLOWLY LIFT NORTH OF THE AREA TONIGHT INTO
MONDAY MORNING. A WEAK MID-LEVEL TROUGH WILL MOVE THROUGH MONDAY.
HIGH PRESSURE BUILDS OVER THE WESTERN ATLANTIC TUESDAY AND
WEDNESDAY...WITH SOUTHERLY RETURN FLOW PROVIDING WARM TEMPERATURES
TO THE REGION. A COLD FRONT WILL APPROACH FROM THE GREAT LAKES
LATE THIS WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
HIGH PRESSURE LOCATED OVER THE NORTHERN ATLANTIC HAS LED TO 
SOUTHERLY FLOW ACROSS THE MID ATLANTIC.  A STATIONARY FRONT IS 
CURRENTLY DRAPED ACROSS VA STATE AND WILL MOVE NORTHWARD AS A WARM 
FRONT BY MONDAY AFTERNOON.  THE WARM FRONT NOSED NORTHWARD LATE THIS 
AFTERNOON AND MIXING OCCURRED TO BREAK UP SOME OF THE LOW CEILINGS.  
AS SFC HEATING CEASED CLOUDS INCREASED AGAIN THIS EVENING.  SFC 
ANALYSIS DOES NOT SHOW A DISTINCT STATIONARY FRONT BUT BELIEVE IT IS 
SITUATED NORTH OF THE BAY AND ACROSS CENTRAL VIRGINIA.  OVERNIGHT... 
LITTLE MOVEMENT OF WARM FRONT AND THEREFORE LITTLE CHANGE TO
CURRENT AIRMASS AND SCATTERED SHOWERS WILL CONTINUE ACROSS CENTRAL
VIRGINIA. HEAVIER SHOWERS TO THE SOUTH HAVE WANED THIS EVENING AND
DO EXPECT THAT TO CONTINUE OVERNIGHT. SATURATED LOW LEVELS
ELSEWHERE WILL LEAD TO DRIZZLE AND PATCHY FOG OVERNIGHT AND MONDAY
MORNING.

AN UPPER LEVEL LOW WILL MOVE ACROSS THE REGION MONDAY AND HELP MIX 
THE LOW CEILINGS.  SHOWERS AND THUNDERSTORMS ARE POSSIBLE ACROSS THE 
CWA IN THE AFTERNOON AND EVENING.  SOUTHERLY FLOW WILL CONTINUE TO 
USHER IN HIGH PWAT AIR AND FCST SOUNDINGS SHOW CAPE VALUES AROUND 
500 J/KG WITH A SLOW STORM MOTION.  HEAVY RAIN WILL BE POSSIBLE IN 
THUNDERSTORM ACTIVITY. 

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
LOW CLDS AND FOG WL CONT TO BE A FACTOR INTO THE MRNG HRS.
HWVR...THE MAY SUN ANGLE WL GRDLY ERODE THE SATD LYR...PERMITTING
THE FNT TO JUMP N OF AREA BY THE AFTN. SOUTH OF THIS FRONT...A
WARM AND A MODESTLY HUMID AIRMASS WILL BE IN PLACE. MAX TEMPS IN
THE 80S EACH DAY ALTHOUGH CLOUDS MAY INHIBIT TEMPS FROM REACHING
80F IN SOME LOCATIONS ON MON.

NAM/GFS/ECMWF PROG A MID-LVL SHORTWAVE TROUGH TO MV THRU THE MID-
ATLC REGION ON MON. LIFT/MOISTURE AHEAD OF THE TROUGH IN CONJUNCTION
WITH DAYTIME HEATING WILL SUPPORT DIURNAL CONVECTION OVER THE CWA.
POPS HIGHEST TOWARD CENTRAL VA/SRN MD BUT STILL IN CHANCE RANGE.

MID-LVL RIDGE BUILDS OVERHEAD TUE AND WED AFTER THE SHORTWAVE
TROUGH EXITS THE AREA. COVERAGE OF SHOWERS AND STORMS WILL BE LOW
TUE AND WED DUE TO AN ABSENCE OF ORGANIZED LIFT AND A STRENGTHENING
SUBSIDENCE INVERSION. MAV/MET DIVERGE HERE. KEPT FCST DRY FOR MOST
OF THE I-95 CORRIDOR AND CHSPK BAY AS WEAK STEERING FLOW WILL
LIMIT HOW FAR EAST CONVECTION PROPAGATES ONCE INITIATED OVER THE
MTS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT WILL APPROACH FROM THE 
GREAT LAKES/MIDWEST REGIONS WED NGT AND THU BEFORE PASSING THRU
THE AREA ON FRI. CHANCES FOR SHOWERS AND STORMS WILL ACCORDINGLY
INCREASE LATE IN THE WEEK AND WILL BE HIGHEST WITH FROPA. ABOVE
NORMAL TEMPS AHEAD OF THE COLD FRONT WILL TREND MUCH COOLER IN
WAKE OF FROPA FRI INTO THE WEEKEND.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
IFR CONDITIONS EXPECTED THIS EVENING AND INTO MONDAY MORNING. SOUTHERLY
FLOW WILL CONTINUE THROUGH THIS PERIOD AND LOW CEILINGS AND VSBYS
EXPECTED.

IFR CONDITIONS LIKELY TO START THE DAY MON BEFORE MRNG STRATUS/
FOG MIX OUT FROM W TO E. PREDOMINATELY VFR CONDITIONS EXPECTED MON
AFTN ALTHOUGH BRIEF RESTRICTIONS IN SHRA/TSRA ARE POSSIBLE.
DIURNAL FOG/LOW CLOUDS POSSIBLE AT NGT AND ERY IN THE MRNG EACH
DAY IN THE MIDWEEK. CHANCES FOR SHRA/TSRA WILL BE LOW DURING THIS
TIME.

&&

.MARINE...
SCA ADVISORY CANCELED FOR THIS EVENING.  

SOUTHERLY FLOW WILL CONTINUE OVER THE WATERS BUT SHOULD STAY UNDER 
SCA CRITERIA.  SHOWERS AND DRIZZLE EXPECTED WITH LOW CEILINGS 
OVERNIGHT.  AN UPPER LEVEL DISTURBANCE WILL CROSS THE REGION MONDAY 
AND SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE.  SLOW STORM MOTION 
AND HIGH MOISTURE WILL LEAD TO HEAVY RAIN IN ACTIVITY.

LGT SLY FLOW ELY IN THE WEEK WILL STRENGTHEN LATER IN THE WEEK.
SCA CONDITIONS POSSIBLE BY THU...WHEN A COLD FRONT APPROACHES FROM
THE NW.

&&

.TIDES/COASTAL FLOODING...
NO TIDAL FLOOD ISSUES EXPECTED IN THE NEAR FUTURE /TNGT OR EVEN
TOMORROW/.

WATER LEVELS SHOULD TICK UPWARD ELY NEXT WEEK WITH SLY FLOW
PERSISTING AND A WAXING GIBBOUS MOON. THIS FAR OUT...STILL SOME
UNCERTAINTY IF POSITIVE ANOMALIES INCREASE ENOUGH TO REACH MINOR
THRESHOLD.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$

UPDATE...SHEFFIELD