Area Forecast Discussion
Issued by NWS Sterling, VA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KLWX 270102 AAA
AFDLWX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
902 PM EDT TUE MAY 26 2015

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OFFSHORE THIS WEEK. A SOUTHERLY FLOW
WILL BRING WARM HUMID CONDITIONS TO THE MID ATLANTIC THROUGH
SATURDAY. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE EACH
AFTERNOON AND EVENING. A COLD FRONT WILL APPROACH THE AREA EARLY
NEXT WEEK.

&&

.NEAR TERM /THROUGH WEDNESDAY/...

SHOWERS HAVE DIMINISHED/WEAKENED CONSIDERABLY IN THE LAST HALF
HOUR WITH NO LIGHTNING SEEN IN THE LAST 30 MINUTES. CURRENT BAND
OF CLOUDS AND LIGHT SHOWERS WILL LIFT NORTH INTO PA TONIGHT ON A
NNE STEERING FLOW. A BAND OF SHOWERS OVER ERN OH AND WRN WV WILL
MOVE EAST INTO THE HIGHLANDS TOWARD DAYBREAK AND THE I-81 CORRIDOR
BY 18Z WED AND TO THE UPPER CHES BAY BY 00Z THU. THESE SHOWERS
MAY PRODUCE BRIEF DOWNPOURS DUE TO VERY HIGH MOISTURE CONTENT AND
HIGH K INDICES BUT FAST STORM MOTION SHOULD KEEP RAINFALL AMOUNTS
MANAGEABLE.


&&

.SHORT TERM /WEDNESDAY NIGHT/...
THE UPPER LEVEL RIDGE MOVES FURTHER EAST WEDNESDAY AND AN UPPER
LEVEL TROUGH MOVES ACROSS THE GREAT LAKES. FALLING HEIGHTS...
MOISTURE AS WELL AS MULTIPLE DISTURBANCES COUPLED WITH A UPPER
LEVEL JET WILL LEAD TO SHOWERS AND THUNDERSTORMS WEDNESDAY.
MOISTURE FROM THE ACTIVITY ACROSS AL/GA WILL LIKELY MOVE INTO THE
MID-ATLANTIC WEDNESDAY MORNING. SHOWERS ARE EXPECTED TO MOVE WEST
TO EAST WEDNESDAY. THINNER CLOUDS ARE EXPECTED EAST OF THE BLUE
RIDGE BY WEDNESDAY AFTERNOON AND WILL LEAD TO HEATING AND MORE
INSTABILITY. SHEAR WILL BE MARGINAL...AROUND 20-30KTS WITH THE
BEST SHEAR NEAR THE POTOMAC HIGHLANDS SIMILAR TO TODAY...TUESDAY.
DUE TO THE MULTIPLE DISTURBANCES THAT MAY MOVE OVER THE REGION
WEDNESDAY...STRONG THUNDERSTORMS ARE EXPECTED ACROSS THE REGION.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
WE ARE IN THE SUMMERTIME PATTERN W/ THE HIGH OFF THE CST. THIS WL
CONT TO DRAW WARMTH AND MOISTURE INTO THE MID ATLC WED NGT-THU
NGT. WHILE TSTMS WL BE PSBL BOTH WED EVE AND THU AFTN THERE DOES
NOT APPEAR TO BE MUCH SHEAR OR A FORCING MECHANISM SO SVR THREAT
LOOKS MARGINAL AT BEST.

TEMPS SHOULD RMN STEADY - HIGHS IN THE 80S...PSBLY A90 IN THE
CITIES. LOWS IN THE 60S...L70S IN THE CITIES.

A WEAK WARM FRONT WILL SLIDE NORTHWARD ACROSS THE MID ATLANTIC
REGION FRIDAY NIGHT. A SHOWER OR THUNDERSTORM COULD LINGER IN PARTS
OF THE AREA WITH LOW TEMPERATURES BOTTOMING OUT IN THE MIDDLE 60S.

A COLD FRONT WILL APPROACH THE REGION SATURDAY...BRINGING A CHANCE
OF SHOWERS AND THUNDERSTORMS TO THE REGION INTO SATURDAY NIGHT.
TEMPERATURES SATURDAY WILL REACH THE MIDDLE 80S WITH LOWS SATURDAY
NIGHT GETTING INTO THE MIDDLE 60S.

THE COLD FRONT SHOULD SLOWLY PUSH THROUGH THE REGION SUNDAY. THE
EUROPEAN MODEL REMAINS THE SLOWER MODEL OVER THE GFS.
HOWEVER...THE GFS MODEL RUNS HAVE BEEN SHOWING THE FRONT SLOWING
DOWN AS WELL. A SLOW-MOVING COLD FRONT TENDS TO BE THE TREND.
SHOWERS AND THUNDERSTORMS WILL FORM AHEAD OF AND ALONG THE FRONT.
TEMPERATURES WILL BE ABOVE NORMAL SUNDAY.

A WEDGE OF HIGH PRESSURE WILL BUILD SOUTHWARD ALONG THE EAST
COAST SUNDAY NIGHT AND MONDAY...HELPING TO COOL CONDITIONS DOWN A
LITTLE. HOWEVER...OVERRUNNING MOISTURE FROM THE SOUTH...PASSING
MID-LEVEL DISTURBANCES TO THE NORTH...AND A DEVELOPING LOW ALONG THE
FRONT COULD BRING ANOTHER THREAT FOR RAIN SHOWERS. THUNDERSTORMS
SHOULD BE LIMITED WITH LOW LEVEL COOLER AIR EVENTUALLY WORKS ITS
WAY INTO THE REGION. TEMPERATURES MAY BE A FEW DEGREES ABOVE NORMAL
EACH PERIOD.

AS THE RIDGE OF HIGH PRESSURE BREAKS DOWN TUESDAY...UPPER LEVEL
DISTURBANCES ARE EXPECTED TO MOVE ACROSS THE OHIO VALLEY INTO THE
LOWER GREAT LAKES. THESE DISTURBANCES COULD POSE A SHOWER THREAT
TUESDAY WITH HIGH TEMPERATURES ONLY IN THE LOWER 80S.

&&

.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
MID-LEVEL DRYING OVERNIGHT COUPLED WITH VERY MOIST LOW-LEVELS MAY
RESULT IN MVFR CIGS ESPECIALLY AT DCA...BWI AND MTN. INCLUDED A
2-3 HR PERIOD OF MVFR CIGS AT THOSE TAF SITES EARLY WED MORNING.
SHOWERS/T-STORMS APPEAR LIKELY AT KMRB WED AFTERNOON AND PERHAPS
BWI AND MTN. ACTIVITY SHOULD BE MORE SCATTERED AT IAD...DCA AND
CHO.

VFR CONDS XPCTD OUTSIDE OF ANY PSBL RW/TRW WED NGT-THU NGT. NO
PROBS XPCTD FRI.

VFR OR MVFR CONDITIONS FRIDAY NIGHT WITH A SHOWER OR THUNDERSTORM
IN THE AREA NEAR CHO OR MRB TERMINAL. VFR ELSEWHERE.

VFR CONDITIONS SATURDAY AT MTN...BWI...DCA TERMINALS. MVFR OR IFR
CONDITIONS AT IAD...CHO...AND MRB TERMINALS FOR SHOWERS AND
THUNDERSTORMS IN THE AREA.

&&

.MARINE...
S WINDS WILL CONTINUE ON THE WATERS. SCA CONDITIONS EXPECTED TO
CONTINUE ON THE LOWER TIDAL POTOMAC AND CHESAPEAKE BAY SOUTH OF
POOLES ISLAND THROUGH TONIGHT. WIND FIELD SUBSIDES NORTH OF SANDY
POINT LATE TONIGHT INTO WEDNESDAY. SHOWERS AND THUNDERSTORMS
EXPECTED WEDNESDAY AFTERNOON AND SOME STORMS MAY PRODUCE GUSTY
WINDS AND HEAVY RAIN WHICH MAY REQUIRE SPECIAL MARINE WARNINGS.

NO MARINE HAZARDS THURSDAY NIGHT.

SMALL CRAFT ADVISORY CONDITIONS POSSIBLE SATURDAY WITH SOUTHERLY
WINDS GUSTING 20 KNOTS.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ531-538-
     539.
     SMALL CRAFT ADVISORY UNTIL 6 PM EDT WEDNESDAY FOR ANZ532>534-
     537-540>543.

&&

$$
SYNOPSIS...LFR
NEAR TERM...LFR
SHORT TERM...HAS
LONG TERM...ABW
AVIATION...LFR
MARINE...LFR


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.