Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 010151
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
951 PM EDT TUE JUN 30 2015

.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN NORTH OF THE AREA THROUGH TONIGHT.
LOW PRESSURE TRACKING THROUGH THE EASTERN GREAT LAKES WILL SLOWLY
DRAG A COLD FRONT NEAR THE AREA WEDNESDAY...WITH THE FRONT PUSHING
THROUGH AND STALLING TO THE SOUTH THROUGH THE END OF THE WEEKEND.

&&

.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
SVR TSTM WATCH HAS BEEN CANCELLED FOR THE REMAINDER OF THE AREA.
UPPER LVL TROF REMAINS THE MAIN PLAYER IN CONVECTION DEVELOPMENT
FOR THE AREA TONIGHT INTO WED AS IT PIVOTS FROM THE GL REGION EAST
INTO THE NORTHEAST. 01Z WATER VAPOR IMAGERY INDICATING EMBEDDED
SHORTWAVE OVER WV TRIGGERING ON GOING CONVECTION...EXTENDING EAST
INTO WESTERN VA/EASTERN WV WHERE THE BETTER INSTABILITY AND SHEAR
STILL RESIDE. ISO STRONG TSTMS STILL PSBL WITH THE ENVIRONMENT
STILL TO BE WORKED OVER...MAINLY THRU 03Z...WITH SCT SHOWERS THEN
EXPECTED TO PUSH ACROSS THE CWA THE REMAINDER OF THE NIGHT AS THE
TROF SWINGS THRU.

THE TROF WL EMERGE OVER THE ERN SHORE BY WED MRNG. A CDFNT WL BE
APPROACHING...ATTENDANT FM LOPRES THAT WL BE TRACKING ACRS QUEBEC
BY THAT TIME. HWVR...THE CDFNT LOOKS QUITE WEAK...AND AM
STRUGGLING TO FIND FORCING MECHANISMS. AMS WL STILL BE QUITE MOIST
BUT NOT THAT UNSTBL. MID LVL LAPSE RATES WL BE DECENT. WL HOLD
ONTO LOW END CHC POPS...HIER THAN MAV/MET...AND CONT TIL SUNSET.

WL STILL BE IN THE WARM SECTOR TMRW...SO TEMPS WL BE SLGTLY MUGGY
WITH HIGHS MID-UPR 80S.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
LOW PRESSURE WILL MOVE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY
THURSDAY MORNING WHILE A COLD FRONT REMAINS STALLED ACROSS MUCH OF
THE EASTERN SEABOARD. SHOWERS ARE EXPECTED TO MOVE INTO THE
HIGHLANDS THURSDAY AFTERNOON AS LOW PRESSURE MOVES ALONG THE STALLED
FRONTAL BOUNDARY. FCST MODELS HAVE SLOWED DOWN THE PROGRESSION OF
SHOWERS MOVING INTO THE REGION. SHOWERS WILL SPREAD ACROSS THE MID-
ATLANTIC THURSDAY NIGHT. HEAVY SHOWERS ARE EXPECTED AS ENHANCED LIFT
OCCURS IN THE ENTRANCE REGION OF A UPPER LEVEL JET. DUE TO THE TIME
OF DAY AND LACK OF INSTABILITY ALOFT...THUNDERSTORMS ARE NOT
EXPECTED AT THIS TIME.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
MAIN STORY THROUGH THE EXTENDED IS CONT CHCS FOR UNSETTLED WX...AS
STUBBORN FRONTAL BOUNDARY REMAINS NEAR/OVER OUR AREA. THERE REMAINS
CONSIDERABLE UNCERTAINTY AND MODEL DISAGREEMENT WITH REGARDS TO
FRONTAL LOCATION THROUGH THE EXTENDED. AS SUCH...IT IS DIFFICULT
DETERMINE THE SPATIOTEMPORAL EXTENT OF ANY ACTIVITY AND DETERMINE
CONVECTIVE VS SHOWER CHCS.

MILLION DOLLAR QUESTION IS WHAT WILL THE WX BE LIKE ON SAT...FOR NOW
HAVE KEPT CHC POPS AND THUNDER...THOUGH THERE IS CERTAINLY BUST
POTENTIAL WITH THIS...AS FRONT COULD BE FAR ENOUGH TO OUR
SOUTH...WHICH WOULD LIMIT INSTABILITY (ELEVATED).

AS MENTIONED YESTERDAY...TEMPS PROGGED TO REMAIN AOB CLIMO NORMS
THROUGH THE EXTENDED...WITH A GRADUAL WARMING TREND THROUGH THE
PERIOD. DEWPOINTS ALSO EXPECTED TO REMAIN AOB 70F...SO NOT EXPECTING
CONDITIONS TO BE VERY OPPRESSIVE.

&&

.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
GENERALLY VFR CONDITIONS FOR THE TAF PERIOD. ISO TSTMS PSBL
TONIGHT...WITH COULD BRIEFLY REDUCE CIGS AND VIS TO SUB-VFR AND
PRODUCE GUSTY WINDS TO 30 KTS. OTHERWISE...WINDS SLY LESS THAN 10
KTS...BCMG LIGHT/VRB AFTR 06Z.

TSRA CVRG LOOKING MUCH LWR ON WED...AS TROF WL BE EAST OF
TERMINALS. A WEAK CDFNT WL BE DROPPING SWD IN THE AFTN-EVNG. ITS
ENTIRELY PSBL THAT THERE WL BE NO TSRA AT ALL. TAFS VFR W/ CIGS
BKN-OVC050-060.

SUB-VFR CONDITIONS POSSIBLE THURSDAY NIGHT AS RAIN MOVES INTO THE
REGION

MAIN CONCERN THROUGH EXTENDED IS POTENTIAL FOR SCATTERED
THUNDERSTORMS EACH DAY...WITH SUB-VFR CONDS POSSIBLE NEAR TSTMS. VFR
CONDS EXPECTED OUTSIDE OF TSTMS.

&&

.MARINE...
SCA REMAINS IN EFFECT FOR THE CHESAPEAKE BAY AND LOWER TIDAL
POTOMAC THRU THE NIGHT WITH SLY WINDS GUSTING TO 18 KTS. SUB-SCA
CONDITIONS THEN EXPECTED AFTR DAYBREAK ON WED...CONTINUING THRU
WED NIGHT. CHC OF TSTMS ON WED AFTN COULD BRING BRIEF GUSTY
WINDS AND REDUCED VSBYS.

SHOWERS WILL OVERSPREAD THE REGION THURSDAY NIGHT AND MAY CAUSE
REDUCED VSBYS.

WINDS EXPECTED TO REMAIN BELOW SCA CRITERIA THROUGH THE
EXTENDED...THOUGH WILL NEED TO MONITOR AS FRONT WILL BE NEAR AREA
EACH DAY. SHOWERS AND TSTMS ARE ALSO POSSIBLE EACH DAY...WHICH
COULD IMPACT MARINE CONCERNS

&&

.TIDES/COASTAL FLOODING...
WATER LVLS RUNNING ABT A FOOT ABV ASTRO NORMS. THE LOWER OF THE
TWO HIGH TIDES ROLLING IN NOW...WHICH WL KEEP LEVELS BELOW ADVY
CRITERIA. HWVR...ISSUES WUD RESULT FROM THE NEXT TIDE...MIDNGT TO
NOON. TOO SOON TO ISSUE ADVY ATTM...BUT ONE MAY BE REQD BEFORE
EVNG OVER.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT WEDNESDAY FOR ANZ531>533-
     537-539>542.
     SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR ANZ534-543.

&&

$$
SYNOPSIS...HTS
NEAR TERM...SEARS/HTS
SHORT TERM...HAS
LONG TERM...MSE
AVIATION...HAS/MSE/SEARS
MARINE...HAS/MSE/SEARS
TIDES/COASTAL FLOODING...


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