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...
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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.
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&& .NEAR TERM /THROUGH TODAY/...
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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.
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&& .SHORT TERM /TONIGHT THROUGH TUESDAY/...
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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.
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&& .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
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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.
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&& .AVIATION /07Z SUNDAY THROUGH THURSDAY/...
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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.
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&& .MARINE...
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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.
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&& .TIDES/COASTAL FLOODING...
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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.
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&& .CLIMATE...
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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.
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&& .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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