Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 310800
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
400 AM EDT SUN AUG 31 2014

.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PERSIST THROUGH TUESDAY WITH AN ACTIVE
PATTERN FOR THE EASTERN SEABOARD. A WEAK COLD FRONT WILL CROSS THE
AREA TUESDAY NIGHT...FOLLOWED BY HIGH PRESSURE.

&&

.NEAR TERM /THROUGH TODAY/...
A BROKEN LINE OF SHOWERS W/ EMBEDDED HEAVY RAIN LINKS UP FROM THE
FL GULF COAST TO LAKE ERIE...JUST TO OUR WEST. THE SYNOPTIC
FEATURES CREATING THIS LARGER ARRANGEMENT OF ACTIVITY IS A COMPLEX
COMBINATION OF WEAK KINKS IN THE UPPER LEVEL FLOW. THE PARENT
FEATURE IS AN OPEN WAVE KICKER THAT IS DRIFTING ACROSS THE NRN
GREAT LAKES REGION...PULLING THE MOISTURE AXIS UP AND OVER A
COMPACT BUT STRONG UPPER RIDGE OVER THE CAROLINA COAST. THE RIDGE
WILL BE EVENTUALLY SUPPLYING OUR AREA - AND MUCH OF THE DEEP
SOUTH...W/ PROLONGED PERIOD OF ABNORMALLY WARM/HUMID TEMPS TO
START OFF THE MONTH OF SEPT.

PATCHY LOW CLOUDS WILL STREAM ACROSS THE REGION AS DEWPOINTS LEVEL
OFF AROUND THEIR HIGHEST POINTS IN THE L70S...W/ TEMPS AT OR JUST
ABOVE THESE VALUES. THIS IS CREATING A HUMID ENVIRONMENT EVEN IN
THE OVERNIGHT HRS...W/ THE INCREASED CLOUD COVER INSULATING THIS
HIGH-HUMIDITY LAYER. THIS IS THE TYPE OF FEEL TO THE AIR WE WILL
HAVE FOR MUCH OF THE UPCOMING WEEK...ESPEC THE FIRST HALF. TEMPS
WILL SLOWLY/STEADILY CLIMB BACK INTO THE 80S HEADING INTO THE MID
MRNG HRS TODAY. LIKE YESTERDAY...THE HIGH AMOUNTS OF CLOUD COVER
WILL LIKELY TEMPER THE POTENTIAL HIGHS - ESPEC ACROSS THE WRN/NRN
HALVES OF THE CWA. ALONG AND SE OF I-95...THE MAX EXPECTED HIGHS
CLOSER TO 90 DEG WILL PROBABLY BE MET W/ LONGER PERIODS OF
SUNSHINE THIS AFTN.

MUCH OF THE INCOMING SHOWER ACTIVITY FROM THE WEST WILL DISSIPATE
AS IT APPROACHES THE HIGHER TERRAIN OF THE CNTRL APLCNS BY DAWN.
INTO THE POST-DAWN HRS...ONLY A FEW SHOWERS WILL SKIRT THE NWRN
SECTIONS OF THE CWA. TOWARD THE EARLY AFTN HRS...WEAK LEE
TROUGHING COULD HELP DEVELOP POCKETS OF SHOWER/TSTM ACTIVITY ALONG
AND E OF THE BLUE RIDGE/APLCNS BUT VERY LOCALIZED. MORE COVERAGE
AND INTENSITY IS EXPECTED HEADING INTO THE AFTN HRS.

REORGANIZATION OF THE BEST CONVECTIVE PARAMETERS WILL LIKELY OCCUR
TOWARD THE LATE AFTN/EVE OVER THE DC/BALT I-95 CORRIDOR AND NE...
EITHER W/ DIFF HEATING BOUNDARIES AND/OR A LOCALIZED LEE TROUGH
AXIS SLIDING THRU THE NRN SECTIONS OF THE CWA. SFC DEWPOINTS WILL
BE PLENTY HIGH TO STEEPEN LOW LEVEL LAPSE RATES IN COMBINATION W/
TEMPS IN THE M-U80S. MLCAPE WILL HOVER AROUND 1000J/KG...W/
LOCALLY HIGHER AND SOME BULK SHEAR IN THE 20-30KT RANGE NEAR THIS
REGION. LOCALLY GUSTY/DAMAGING WINDS POSSIBLE W/ THE STRONGEST
ACTIVITY AND POSSIBLY ROTATION EMBEDDED W/IN A LINEAR COMPLEX.
PWATS HOVERING IN THE 2-2.5" RANGE THIS AFTN/EVE WILL ALSO GIVE
LOCALIZED AREAS THE HEIGHTENED POTENTIAL FOR BRIEF TORRENTIAL
RAINS BUT POSSIBLY ENOUGH FOR FLOODING UNDER TRAINING CELLS.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
AFTER THE EVE CONVECTION HAS DISSIPATED OFF AND MOVED EAST...
ANOTHER REGIONAL BATCH OF LIGHT/MOD RANGE IS TAGGED BY NEAR TERM
GUIDANCE AS MOVING ALONG THE MASON-DIXON LINE AS WELL - KEEPING
PRECIP CHANCES ALIVE INTO EARLY MON. AS THE BACK END OF THIS
FEATURE PASSES BY TO THE NORTH...PRECIP CHANCES WILL REMAIN IN THE
LOW CHANCE RANGE THRU MON AFTN/EVE ACROSS THE ERN HALF OF THE CWA
BUT MAINLY OF A LIGHT/SCTD NATURE...OUTSIDE OF A FEW TSTMS. THE
RELATIVE LACK OF ACTIVITY AND CLEARING SKIES FROM WEST-TO-EAST
WILL ALLOW TEMPS TO CLIMB BACK INTO THE U80S AND SOME L90S FOR THE
AREA ON MON AFTN...W/ DEWPOINTS STANDING PAT IN THE U60S/L70S -
ANOTHER MUGGY DAY FOR THE AREA.

WEAK RIDGING CROSSES THE CENTRAL MID-ATLANTIC MONDAY NIGHT INTO
TUESDAY...MAKING FOR A REPRIEVE IN THUNDERSTORMS FOR 12-18 HRS. WITH
THE BERMUDA HIGH IN PLACE...EXPECT TUESDAY TO HAVE THE HIGHEST
TEMPERATURE DAY SINCE JULY. MAX TEMPS LOW TO MID 90S ACROSS LOWER
ELEVATIONS.

THE NEXT COLD FRONT APPROACHES LATE TUESDAY AND CROSSES THAT NIGHT.
WITH PLENTY OF ENERGY FROM THE HOT DAY...EXPECT AT LEAST ISOLATED
SEVERE WEATHER...PARTICULAR FOR WRN ZONES THAT ARE PROGGED TO GET
THE EVENING ACTIVITY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE BUILDS IN BEHIND WITH CONTINENTAL AIR (NOT CANADIAN)
SO TEMPERATURE REMAIN ABOVE NORMAL. EXPECT MAX TEMPS AROUND 90F
WEDNESDAY THROUGH FRIDAY. RETURN FLOW AND ACTIVE WEATHER RETURNS
LATE FRIDAY INTO THE WEEKEND.

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
HIGH HUMIDITY LEVELS ARE HERE FOR THE NEXT FEW DAYS AND ARE
ALREADY HELPING TO PRODUCE LOCALIZED MVFR CIGS...ESPEC NEAR THE MD
CHES BAY. OTHER POCKETS OF HIGH-END MVFR VSBYS AND CIGS ARE
DOTTING THE MAP ACROSS INLAND AREAS AS WELL...MAINLY AFFECTING THE
REGION THRU MID MRNG. SCTD SHOWERS/TSTMS WILL BECOME MORE POSSIBLE
AND WIDESPREAD LATER THIS AFTN/EVE BUT LOCALIZED. SLY WINDS WILL
PERSIST INTO MON...ALONG W/ A FEW HIT/MISS SHOWERS AS WELL THRU
MON EVE.


BRIEF HIGH PRESSURE/VFR TUESDAY ON A HOT DAY (MAX TEMPS IN THE MID
90S). SCATTERED STRONG THUNDERSTORMS TUESDAY NIGHT AS A WEAK COLD
FRONT CROSSES THE REGION. HIGH PRESSURE/VFR OUTSIDE OF POTENTIAL
MORNING FOG MID TO LATE WEEK.

&&

.MARINE...
SLY FLOW ACRS THE MARINE AREA THRU THE WKND. MARINE OBS IN THE
LOW-MID TEEN GUSTS. IT/LL BE A SIMLR SITUATION SUNDAY...THO DONT
THINK THE MIXING WL BE QUITE AS GOOD. IN ADDITION...POTL TSRA WUD
PROVIDE STRONGER WIND GUSTS.

SUB SCA SWLY FLOW MONDAY NIGHT THROUGH TUESDAY. WEAK COLD FRONT
BRINGS WLY FLOW LATE TUESDAY NIGHT THROUGH WEDNESDAY. HIGH PRESSURE
OVERHEAD WEDNESDAY NIGHT AND THURSDAY.

&&

.TIDES/COASTAL FLOODING...
DEPARTURES AT ANNAPOLIS ARE AROUND 1 FEET...AND WINDS SHOULD
REMAIN SLY...SO ANTICIPATE ADDTL INCREASES THROUGH THE WKND. THE
NEXT HIGH TIDE SUN MRNG WL NEED TO BE WATCHED FOR POSSIBLE MINOR
FLOODING. NONETHELESS...THIS WL BE AN ISSUE THROUGH THE WKND WITH
NEW MOON AND SOUTHERLIES.

&&

.CLIMATE...
BWI AIRPORT HAS NOT HIT 90F THIS MONTH. UPPER 80S ARE FORECAST
TODAY. THIS WOULD BE THE FIRST AUGUST SINCE 1984 THAT BALTIMORE DID
NOT HIT 90F. THE ONLY OTHER SUCH YEAR IN THE BALTIMORE TEMPERATURE
RECORD IS 1904.

&&

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

&&

$$
SYNOPSIS...BAJ
NEAR TERM...GMS
SHORT TERM...GMS
LONG TERM...BAJ
AVIATION...GMS/BAJ
MARINE...GMS/BAJ
TIDES/COASTAL FLOODING...GMS/LEE
CLIMATE...BAJ






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