FXUS61 KLWX 200731
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
331 AM EDT MON MAY 20 2013

.SYNOPSIS...
A WARM FRONT WILL PASS THROUGH THE AREA TODAY WHILE AN UPPER-LEVEL 
DISTURBANCE MOVES THROUGH THE AREA. HIGH PRESSURE OVER THE ATLANTIC 
WILL PROVIDE A SOUTHERLY FLOW FOR TUESDAY THROUGH 
THURSDAY...BRINGING WARM AND HUMID CONDITIONS. A COLD FRONT WILL 
PASS THROUGH THE AREA LATE IN THE WEEK AND COOLER CONDITIONS WILL 
RETURN FOR NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
CURRENT ANALYSIS SHOWS A STATIONARY BOUNDARY OVER THE REGION EARLY 
THIS MORNING WHILE UPPER-LEVEL LOW PRESSURE SLOWLY MOVES INTO THE 
AREA FROM WEST VIRGINIA. 

THE STATIONARY BOUNDARY SEPARATES WARM AND MOIST AIR TO THE SOUTH 
AND WEST FROM COOLER MARINE AIR TO THE NORTH AND EAST. WIDESPREAD 
LOW CLOUDS ALONG WITH FOG/DRIZZLE ARE EXPECTED TO THE NORTH AND  
EAST OF THE BOUNDARY ACROSS NORTHEASTERN MARYLAND. HOWEVER...PLENTY 
OF MOISTURE IS TRAPPED UNDERNEATH THE NOCTURNAL INVERSION SO AREAS 
OF LOW CLOUDS AND FOG/DRIZZLE ARE ALSO EXPECTED SOUTH AND WEST OF 
THE BOUNDARY. A FEW SHOWERS ARE POSSIBLE EARLY THIS 
MORNING...ESPECIALLY CLOSER TO THE UPPER-LEVEL LOW ACROSS CENTRAL 
VIRGINIA. 

THE STATIONARY BOUNDARY WILL MOVE NORTH AS A WARM FRONT LATER THIS 
MORNING AND AFTERNOON. SOUTHERLY WINDS BEHIND THE BOUNDARY WILL 
USHER IN WARM AND HUMID CONDITIONS. THE UPPER-LEVEL LOW WILL SLOWLY 
MOVE INTO THE REGION DURING THIS TIME. THE COMBINATION OF WARM AND 
HUMID CONDITIONS ALONG WITH COOLER AIR ALOFT WILL CAUSE AN UNSTABLE 
ATMOSPHERE THIS AFTERNOON. SHOWERS AND T-STORMS ARE EXPECTED TO 
DEVELOP DURING THIS TIME. A LIGHT WIND FIELD AND INSTABILITY 
REMAINING SOMEWHAT LIMITED DUE TO CLOUD COVER SHOULD KEEP THE SEVERE 
THREAT LOW. SCATTERED SHOWERS/T-STORMS MAY CONTINUE INTO THIS 
EVENING...BUT DRY CONDITIONS ARE EXPECTED OVERNIGHT DUE TO THE LOSS 
OF DAYTIME HEATING.

WARM AND HUMID CONDITIONS WILL PERSIST OVERNIGHT WITH MIN TEMPS 
HOLDING IN THE 60S FOR MOST AREAS. PLENTY OF MOISTURE UNDERNEATH THE 
NOCTURNAL INVERSION WILL RESULT IN AREAS OF LOW CLOUDS/FOG.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
MID-ATLANTIC WILL RESIDE IN A WARM SECTOR DURING THE MID-WEEK. THIS 
WILL ALLOW FOR A WARM UP TUESDAY THROUGH WEDNESDAY...WITH MAXIMA IN 
THE MID 80S. IF THERE IS MORE SUNSHINE...THEN MAXIMA COULD EVEN 
REACH UPPER 80S IN SOME LOCATIONS. 

TUESDAY MORNING MAY START OFF WITH SOME FOG/STRATUS...BUT CLOUDS 
SHOULD BREAK FOR SOME SUNSHINE DURING THE AFTERNOON. MODELS SHOW 
MOISTURE IN PLACE...AND SOME INSTABILITY AS WELL HOWEVER AM HAVING 
TROUBLE FINDING ANY GOOD FORCING/FOCUSING MECHANISMS FOR CONVECTION 
THEREFORE CONTINUE TO FAVOR A DRY FORECAST FOR TUESDAY WITH ONLY 
ISOLATED CONVECTION ACROSS THE NORTHWEST.

AIR MASS REMAINS THE SAME ON WEDNESDAY. MODELS HINT AT A BETTER 
CHANCE OF DIURNAL CONVECTION SO HAVE INCLUDED CHANCE POPS IN THE 
FORECAST FOR SCATTERED THUNDERSTORMS ACROSS THE CWA.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
SLIGHT HEIGHT FALLS ARE FORECAST TOWARD THE END OF THE WEEK AS AN 
UPPER TROUGH APPROACHES...IN TANDEM WITH A COLD FRONT. THERE IS SOME 
QUESTION REGARDING TIMING OF THE FROPA...LATEST GUIDANCE SUGGESTING 
LATE THURSDAY INTO EARLY FRIDAY. DUE TO UNCERTAINTY HAVE CHANCE POPS 
IN THE THURSDAY THROUGH FRIDAY TIME FRAME...AND WE CAN FINE TUNE THE 
TIMING AS WE GET CLOSER. 

THERE IS GOOD AGREEMENT THAT THE FRONT WILL HAVE MOVED THROUGH THE 
AREA BY THE WEEKEND...FAVORING A COOLER/DRIER AIR MASS. FORECAST 
REFLECTS MOSTLY CLEAR SKIES AND TEMPERATURES NEAR CLIMATOLOGY.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
PLENTY OF MOISTURE REMAINS TRAPPED UNDERNEATH THE NOCTURNAL 
INVERSION. LOW CLOUDS AND AREAS OF FOG WILL CAUSE IFR/SUB IFR 
CIGS/VSBYS EARLY THIS MORNING. A WARM FRONT WILL PASS THROUGH THE 
TERMINALS LATER THIS MORNING AND CONDITIONS WILL IMPROVE BY LATE 
MORNING/EARLY AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS ARE 
EXPECTED...MAINLY THIS AFTERNOON AND EVENING. AREAS OF LOW 
CLOUDS/FOG ARE POSSIBLE AGAIN TONIGHT.

THERE IS THE POTENTIAL FOR SOME FOG/STRATUS EARLY 
TUESDAY...PARTICULARLY IF SOME OVERNIGHT CLEARING TAKES PLACE AS 
LOW LEVEL MOISTURE REMAINS. BUT CONFIDENCE REMAINS ONLY LOW-MODERATE 
ON OCCURRENCE ATTM. VFR EXPECTED TO PREVAIL THE BALANCE OF TUESDAY. 
CHANCE OF THUNDERSTORMS RETURNS FOR WEDNESDAY AFTERNOON...AND 
SHRA/TSRA REMAIN POSSIBLE UNTIL A COLD FRONT MOVES THROUGH LATE 
THURSDAY INTO EARLY FRIDAY. 

&&

.MARINE...
A STATIONARY BOUNDARY OVER THE WATERS WILL MOVE TO THE NORTH AS A 
WARM FRONT TODAY. SOUTHERLY WINDS ARE EXPECTED TODAY THROUGH TONIGHT 
BEHIND THIS BOUNDARY. HOWEVER...WIND SPEEDS WILL REMAIN BELOW SCA 
CRITERIA. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED...MAINLY 
THIS AFTERNOON AND EVENING.

SOUTHERLY WINDS ARE EXPECTED DURING THE MID WEEK UNTIL A COLD FRONT 
MOVES THROUGH TOWARD THE END OF THE WEEK SWITCHING WINDS TO THE 
NORTHWEST. SOUTHERLY FLOW CHANNELLING UP THE BAY COULD BRING 
MARGINAL SCA CONDITIONS UP THE BAY PARTICULARLY DURING THE LATE 
AFTERNOON/EVENINGS. 

&&

.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES REMAIN NEAR NORMAL EARLY THIS MORNING. SOUTHERLY 
WINDS ARE WILL DEVELOP OVER THE WATERS TODAY AND ANOMALIES ARE 
EXPECTED TO INCREASE. HOWEVER...THE HIGH TIDE THIS AFTERNOON WILL BE 
THE LOWER OF THE TWO. WILL HAVE TO WATCH SOUTHERLY FLOW DURING THE
MID-WEEK AS IT MAY SUPPORT AN INCREASE IN DEPARTURES AGAIN. BUT
CBOFS KEEPS WATER LEVELS BELOW MINOR THRESHOLDS THROUGH HIGH TIDES
TUESDAY AFTERNOON.

&&

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

&&

$$
SYNOPSIS...BJL/BPP
NEAR TERM...BJL
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...BJL/BPP
MARINE...BJL/BPP
TIDES/COASTAL FLOODING...BJL/BPP