Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 300758 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 358 AM EDT SAT AUG 30 2014 .SYNOPSIS... HIGH PRESSURE OFF CAPE COD WILL MOVE SOUTHEAST AND BECOME A BERMUDA HIGH FOR THE HOLIDAY WEEKEND AND THROUGH TUESDAY. A COLD FRONT WILL CROSS THE AREA TUESDAY NIGHT. HIGH PRESSURE WILL FOLLOW FOR THE SECOND HALF OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... TEMPERATURES AND HUMIDITY WILL BE REBOUNDING TODAY AS HIGH PRESSURE SLIPS OFFSHORE. ANY ISOLATED TSTMS TODAY WILL BE OVER WEST CENTRAL VA AND EASTERN WV. CLOUD COVER WILL BE TRICKY TODAY AS THERE IS A DECENT SHIELD OF 5000FT CEILINGS OVER A LARGE PART OF THE FORECAST AREA EARLY THIS MORNING. ALL IN ALL PARTLY OR VARIABLY CLOUDY FOR MOST TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... SAT NIGHT HUMIDITY INCREASES...WEAK SHORT WAVE MOVES OVERHEAD AND LEE TROF BEGINS TO ASSERT ITSELF. ALL OF THAT SHOULD ALLOW FOR ISOLATED STORMS EAST OF THE BLUE RIDGE OVERNIGHT WITH SCATTERED STORMS TO THE WEST. SUNDAY FEATURES THE BEST CHANCE OF STORMS OVER THE HOLIDAY WEEKEND RIGHT NOW. LEE TROF IN PLACE...WEAK SHORT WAVE MOVING IN...HI TEMPS IN THE MID 80S TO AROUND 90...SOME WEAK JET DIVERGENCE AT HIGHER LEVELS...ALL OF THESE ARE INGREDIENTS FOR SOME STORMS. THE MOST DISTURBING PARAMETER IS THE GFS FORECASTING PRECIPITABLE WATER TO BE OVER 2 INCHES OVER A WIDE AREA. WHILE THERE IS ENOUGH WIND IN THE ATMOSPHERE TO KEEP STORMS MOVING...COULD BE ISOLATED AREAS OF FLASH FLOODING WITH THAT MUCH MOISTURE. WILL MAINTAIN MENTION IN HAZARDOUS WEATHER OUTLOOK FOR SUNDAY INTO SUNDAY NIGHT. MONDAY WILL STILL BE WARM AND HUMID...BUT PRECIPITABLE WATERS FALL...LEE TROF SLACKENS...AND SHORT WAVE MOVES OUT. FOR THESE REASONS EXPECT LESSER CHANCES OF STORMS MONDAY THAN SUNDAY FOR ANY ONE SPOT. STILL SCT STORMS EXPECTED THOUGH. && .LONG TERM /MONDAY THROUGH FRIDAY/... ELEVATED HEAT INDICES WILL CONTINUE TO BE A CONCERN HEADING INTO MIDDLE OF NEXT WEEK. DEWPOINTS WILL CONTINUE HOVERING AROUND THE 70F DEG MARK...WHICH IS PLENTY HUMID IN COMBINATION W/ DAILY HIGHS POKING ABOVE 90F DEG. FROM LATE MON INTO TUE...A POTENT AND LARGE- SCALE LOW PRESSURE SYSTEM WILL SWINGING THRU THE GREAT LAKES/UPPER MIDWEST. THE PARENT LOW WILL BE WELL TO THE NORTH...PULLING UP INTO THE SRN HUDSON BAY REGION/QUEBEC. THE DYNAMICS OF THIS SYSTEM WILL HEAD DUE EAST...STRADDLING THE US/CANADA BORDER AND TAKING THE HEAVIEST PRECIP ALONG W/ IT - WELL TO OUR NORTH TUE INTO WED. SOME RESIDUAL SHOWERS HANGING AROUND THE COASTAL ZONES OVER TO THE I-95 CORRIDOR FROM LATE MON NIGHT WILL BE DISSIPATING EARLY TUE...AS HIGH PRES BUILDS IN FROM THE SRN APLCNS. THIS HIGH...IN CONCERT W/ THE OFFSHORE AND LARGER BERMUDA HIGH WILL AGAIN PRESS THE HEAT/HUMIDITY UP INTO THE MID ATLC. THE RELATIVE LACK OF ORGANIZED FORCING ACROSS THE REGION WILL KEEP SKIES GENERALLY CLEAR TUE WHICH WILL BE LITTLE RELIEF IN TERMS OF THE HOT CONDITIONS. MORE DRY AND HOT WEATHER TO CARRY US THRU THE SECOND HALF OF THE WEEK...THOUGH TUE MAY BE THE WARMEST DAY - ALBEIT ONLY BY COUPLE OF DEG. LATE TUE EVE...THE TAIL END OF THE COLD FRONT FROM THE GREAT LAKES LOW WILL LIKELY CROSS THE REGION. THE FRONT WILL CARRY SOME SCATTERED SHOWERS AND TSTMS. GOOD LOW LEVEL LAPSE RATES DURING PEAK HEATING AND MODEST INSTABILITY WILL MAKE FOR AT LEAST A HANDFUL OF STRONG TSTMS...MORE IF OUTFLOW-DRIVEN. ZONAL UPPER FLOW OVER THE NRN HALF OF THE CONUS FOR THE SECOND HALF OF WEEK WILL ESSENTIALLY HOLD OUR WARM/HUMID AIRMASS IN PLACE. WHILE THE COLD FRONT KICKS OFF PRECIP A COUPLE OF STATES TO OUR SOUTH...THE MID-ATLC WILL BE MAINLY DRY TO CLOSE OUT THE WEEK UNTIL AN UPPER SHORTWAVE ARRIVES FROM THE WEST LIKELY NEXT WEEKEND. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... WITH INCREASING LOW LVL HUMIDITY...OVERNIGHT FOG WILL BE AN INCREASING ISSUE THRU THE WEEKEND. EXPECT SOME LIGHT FOG AT CHO TONIGHT...THEN 3-5SM FOG FOR DULLES AND AREAS WEST TOMORROW NIGHT. ALSO TARGETED IFR POSSIBLE AT TIMES WITH ANY THUNDERSTORMS. HOT/HUMID AIRMASS STAYS IN PLACE FOR THE NEXT SEVERAL DAYS. TUE MAY BE THE WARMEST DAY OF THE STRETCH BUT NOT BY MUCH. DAILY HIGHS IN THE U90S AND DEWPOINTS HAVING HUMID FOR THIS TIME OF YEAR. ONLY BRIEF AND SHORT-LIVED PERIODS OF PRECIP POSSIBLE INTO MID NEXT WEEK...BUT MAINLY DRY AND MOSTLY SUNNY EACH DAY. && .MARINE... WILL HAVE TO MONITOR CENTRAL AND SOUTHERN MD CHES BAY FOR SMALL CRAFT GUSTS LATE TODAY AND TONIGHT...AND THEN AGAIN LATE SUNDAY INTO SUN EVENING. IT WILL BE BORDERLINE. OFFSHORE HIGH PRES WILL CONTINUE TO STEER WARM/HUMID AIR UP ACROSS THE ERN SEABOARD. ONLY MINOR PERIODS OF SLY CHANNELING AND/OR SCA CONDITIONS POSSIBLE INTO THE MIDDLE OF NEXT WEEK. A WEAK COLD FRONT WILL LIKELY CROSS THE WATERS BY LATE TUE/EARLY WED. A FEW TSTMS POSSIBLE W/ THIS FEATURE. HIGH PRES THEN BUILDS IN THROUGH THE REST OF THE WEEK. && .COASTAL FLOODING... WITH SOUTHEAST WINDS BECOMING S...AND NOT TOO FAR FROM NEW MOON...CONTINUE TO MONITOR THE SLOWLY INCREASING TIDAL ANOMALY. NOT ANY TROUBLE YET...BUT COULD BE IN THE MOST SENSITIVE SPOTS LIKE ANNAPOLIS WITHIN 24 HRS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY 4 PM SATURDAY UNTIL 4 AM SUNDAY FOR ANZ533-534. && $$ SYNOPSIS...CAS NEAR TERM...CAS SHORT TERM...CAS LONG TERM...CAS/GMS AVIATION...CAS/GMS MARINE...CAS/GMS COASTAL FLOOD...CAS

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