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 011841
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
241 PM EDT MON SEP 1 2014

.SYNOPSIS...
A BERMUDA HIGH WILL PERSIST THROUGH TUESDAY. A COLD FRONT WILL
CROSS THE AREA TUESDAY NIGHT...FOLLOWED BY HIGH PRESSURE THROUGH
THE REST OF THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
CONVECTIVE TEMPERATURES HAVE BEEN REACHED ACROSS THE CWA...CU HAVE
BECOME MORE PRONOUNCED AND AN UPTICK IN SHOWERS HAVE BEEN OBSERVED
OVER THE LAST HOUR OR TWO.

CONVECTION WILL LIKELY GROW INTO THUNDERSTORMS AS PEAK HEATING
CONTRIBUTES TO INCREASED INSTABILITY. LOW LEVELS REMAIN MOIST AS
WELL...WITH DEWPOINTS WITHIN A COUPLE DEGREES OF 70 DEGREES ALTHOUGH
PRECIPITABLE WATERS LIKELY HAVE DECREASED A LITTLE BIT DUE TO
MID-LEVEL DRY AIR.

BASED ON RADAR TRENDS AND INCORPORATING LATEST RUNS OF HIGH
RESOLUTION MODELS...CONVECTION OVER WESTERN MD/EASTERN WV/NORTHERN
VA WILL MOVE EASTWARD OVER THE NEXT SEVERAL HOURS. ADDITIONAL
CONVECTION UPSTREAM COULD ALSO MAKE IT INTO THE CWA BEFORE SUNSET.
GIVEN THE HIGH MOISTURE ENVIRONMENT...HEAVY RAINFALL WILL BE THE
PRIMARY CONCERN WITH THUNDERSTORMS BUT STORM MOTION SHOULD BE
SUFFICIENT ENOUGH TO LIMIT FLASH FLOOD POTENTIAL. CAN/T RULE OUT
LOCALLY GUSTY WINDS IN STRONGER STORMS EITHER BUT GIVEN WEAK SHEAR
SEVERE RISK IS LOW.

MUCH OF THE ACTIVITY WILL MOVE EAST/DISSIPATE BY THE TIME THE SUN
SETS...ALTHOUGH CAN/T RULE OUT A ROGUE SHOWER ACROSS THE HIGHLANDS
THROUGH MUCH OF THE EVENING.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
COLD FRONT WILL STILL BE LOCATED ACROSS THE OHIO VALLEY AT 12Z TUE.
BUT FRONT WILL MARCH EASTWARD THROUGH THE DAY...MAKING IT TO THE
POTOMAC HIGHLANDS BY LATE AFTERNOON. PRE-FRONTAL ENVIRONMENT WILL BE
WARM AND MOIST...BUT CONVECTION LIKELY WAITS UNTIL THE FRONT GETS
CLOSER TO THE CWA AND HAVE POPS EXPANDING EASTWARD WITH TIME HIGHEST
IN THE EVENING ACROSS THE INTERSTATE 95 CORRIDOR.

THERE IS THE RISK FOR A FEW STORMS TO BECOME SEVERE /DAMAGING WIND
GUSTS/ TUESDAY...ESPECIALLY BEFORE DARK DUE TO THE COMBINATION OF
INSTABILITY AND INCREASED SHEAR. CONFIDENCE IS LOWER FURTHER
DOWNSTREAM ONCE THE SUN SETS. FRONT MOVES THROUGH AT NIGHT. POPS
LOWER FROM WEST TO EAST.

DRIER AIR MOVES IN FOR WEDNESDAY WITH THE RETURN OF SUNSHINE. WHILE
DEWPOINTS ARE LOWER...DOWNSLOPING WILL SUPPORT ABOVE NORMAL
TEMPERATURES WHICH STILL MAY BE NEAR 90. SAME TYPE OF SCENARIO ON
THURSDAY.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
WEAK SURFACE TROUGH...MOISTURE AND WEAK PVA MAY BE ENOUGH TO SUPPLY
A SLIGHT CHANCE OF SHOWERS/THUNDERSTORMS FRIDAY. INCREASED MOISTURE
AND THE PASSAGE OF COLD FRONT WILL SUPPORT DEVELOPMENT OF STRONGER
ACTIVITY OVER THE WEEKEND AND INTO MONDAY.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
SCT SHRA/TSRA WILL MOVE EASTWARD ACROSS THE HUBS OVER THE NEXT
SEVERAL HOURS...LIKELY ENDING BY SUNSET. VCTS CURRENTLY IN
TAFS...BASED ON RADAR TRENDS MAY NEED TO AMEND FOR TSRA INCLUSION.
REST OF THE NIGHT INTO TUESDAY MORNING SHOULD BE DRY...TSRA POSSIBLE
AGAIN TUESDAY AFTERNOON/EVENING AHEAD OF A COLD FRONT.

NO SIGNIFICANT WEATHER EXPECTED MID TO LATE WEEK.

&&

.MARINE...
PRIMARY CONCERN THIS EVENING WILL BE GUSTY WINDS AND LIGHTNING IN
SCATTERED SHOWERS AND THUNDERSTORMS THAT AFFECT THE WATERS THROUGH
EARLY EVENING. ACTIVITY SHOULD DIMINISH WITH SUNSET. APPROACHING
COLD FRONT WILL LIKELY PRODUCE SCATTERED THUNDERSTORMS LATE TUESDAY
AFTERNOON AND EVENING AS WELL...WITH GUSTY WINDS AGAIN POSSIBLE.
FRONT MOVES THROUGH TUESDAY NIGHT WITH HIGH PRESSURE BUILDING IN FOR
WEDNESDAY.

SOUTHERLY CHANNELLING/SCA CONDITIONS COULD BE POSSIBLE LATE
FRIDAY. COLD FRONT EXPECTED TO MOVE THROUGH OVER THE WEEKEND.

&&

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

&&

$$
SYNOPSIS...BPP/CEM
NEAR TERM...BPP
SHORT TERM...BPP
LONG TERM...CEM
AVIATION...BPP/CEM
MARINE...BPP/CEM







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