Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Graphics & Text | 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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 031906 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 306 PM EDT MON AUG 3 2015 .SYNOPSIS... A COLD FRONT WILL GRADUALLY PUSH SOUTHEAST INTO THE AREA TONIGHT AND TUESDAY. THE FRONT WILL SLIDE SOUTH OF THE AREA TUESDAY NIGHT ALLOWING HIGH PRESSURE TO BUILD IN WEDNESDAY. THE FRONT WILL PUSH BACK NORTH INTO THE AREA ON THURSDAY AS A WAVE OF LOW PRESSURE RIDES EASTWARD ALONG IT. THIS LOW WILL CLEAR THE AREA FRIDAY TAKING THE FRONT WITH IT. HIGH PRESSURE WILL BUILD IN BEHIND IT AND DOMINATE OVER THE WEEKEND. && .NEAR TERM /THROUGH TUESDAY/... LOW PRESSURE IS LOCATED IN QUEBEC THIS AFTERNOON WHILE A COLD FRONT STRETCHES INTO THE MIDWEST. A BERMUDA HIGH PERSISTS TO THE EAST. A SFC TROUGH IS LOCATED ACROSS THE MID-ATLANTIC. TEMPERATURES ARE IN THE UPPER 80S TO LOW 90S ACROSS THE REGION. A CU FIELD HAS DEVELOPED IN VICINITY OF THE SFC TROUGH MAINLY ACROSS SE VA THIS AFTERNOON. SHOWERS AND THUNDERSTORMS HAVE FORMED ACROSS THE TIDEWATER REGION WHERE MLCAPE VALUES ARE 1-2K J/KG AND DEWPTS ARE IN THE UPPER 60S TO NEAR 70. FURTHER NORTH...DEWPTS ARE IN THE UPPER 50S TO LOW 60S AND IT HAS TAKEN MORE TIME TO DEVELOP A CU FIELD. LITTLE FORCING WILL LIMIT CONVECTION THIS AFTERNOON. THE COLD FRONT ACROSS THE MIDWEST WILL MOVE EASTWARD THIS EVENING AND SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE OHIO VALLEY. ISO-SCT ACTIVITY IS EXPECTED TO MOVE INTO THE POTOMAC HIGHLANDS BUT MOST SHOULD STAY WEST OF THE BLUE RIDGE INTO TUESDAY MORNING. FCST SOUNDINGS SHOW ELEVATED INSTABILITY AND THEREFORE THE POTENTIAL FOR A THUNDERSTORM EXISTS OVERNIGHT. THE FRONT WILL MOVE EASTWARD OVERNIGHT. FCST MIN TEMPS RANGE IN THE MID TO UPPER 60S WEST OF THE BLUE RIDGE TO THE LOW TO MID 70S ALONG AND EAST OF I-95. THE FRONT STALLS NEAR THE I-95 CORRIDOR TUESDAY. COOLER AND DRIER AIR WILL FILTER INTO THE REGION BEHIND THE FRONT BUT WARM AND HUMID CONDITIONS ARE EXPECTED NEAR THE FRONT. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO FORM IN THE EARLY AFTERNOON TUESDAY EAST OF I-95 WITH THE BEST CHANCE ACROSS SOUTHERN MD AND SURROUNDING WATERS. FCST SOUNDINGS SHOW THE POTENTIAL OF 2-3K J/KG OF INSTABILITY AND GT 30KTS OF 0-6KM SHEAR. AN UPPER LEVEL JET WILL ALSO BE LOCATED ACROSS THE NRN MID-ATLANTIC THAT SHOULD ENHANCE UPPER LEVEL DIVERGENCE. STORMS MAY BECOME STRONG TO SEVERE ACROSS THE HIGHLIGHTED AREA. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE WILL MOVE INTO THE CENTRAL APPALACHIANS TUESDAY NIGHT AND SHIFT SLOWLY EAST FROM THERE...REACHING THE DC METRO THURSDAY MORNING. TEMPERATURES WEDNESDAY WILL BE A FEW DEGREES COOLER AND DEW POINTS WILL DROP INTO THE UPPER 50S IN MANY AREAS. SUNSHINE WILL ALSO PREDOMINATE WEDNESDAY...BUT AN APPROACHING WAVE OF LOW PRESSURE TO THE WEST WILL CAUSE CLOUDS TO INCREASE BY THURSDAY MORNING. AS THIS WAVE APPROACHES DURING THE DAY THURSDAY...RAIN SHOWERS AND POSSIBLY SOME THUNDERSTORMS WILL BEGIN TO ENCROACH FROM WEST TO EAST. CLOUDS WILL TEND TO KEEP TEMPERATURES SLIGHTLY COOLER ON THURSDAY BUT DEW POINTS WILL RISE BACK INTO THE MIDDLE 60S IN MUCH OF THE AREA. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... MODELS ARE IN MUCH BETTER AGREEMENT IN TERMS OF THE TIMING OF A WAVE OF LOW PRESSURE THURSDAY NIGHT INTO FRIDAY...HOWEVER THE TRACK AND STRENGTH STILL DIFFERS FROM MODEL TO MODEL AND RUN TO RUN. FELT CONFIDENT ENOUGH TO GO WITH LIKELY POPS ACROSS MOST OF THE AREA THURSDAY NIGHT INTO FRIDAY IN A PSEUDO WARM AIR ADVECTION PATTERN. CONVECTIVE POTENTIAL WILL DEPEND ON IF THE LOW PRESSURE AREA PASSES NORTH OR SOUTH OF THE AREA. THE LOW WILL PASS EAST AND OUT TO SEA...LIKELY BRINGING THE FRONT WITH IT BY THE WEEKEND. HIGH PRESSURE SHOULD RETURN OVER THE WEEKEND...BEFORE ANOTHER SYSTEM APPROACHES BY EARLY NEXT WEEK. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... VFR CONDITIONS EXPECTED TONIGHT AND TUESDAY. SHRA/TSRA ARE POSSIBLE MRB TONIGHT. ACTIVITY SHOULD WANE AS IT MOVES EASTWARD AND COVERAGE SEEMS TO BE ISOLATED. A COLD FRONT WILL CROSS THE REGION TONIGHT AND INTO TUESDAY. SHRA/TSRA POSSIBLE AT BWI/MTN TUES AFTERNOON. SRLY WINDS WILL CONTINUE AT THE TERMINALS TONIGHT. WINDS SHOULD BECOME WESTERLY TUESDAY. VFR TUE NIGHT-THU MORNING ALL TERMINALS AS HIGH PRESSURE BUILDS IN. WINDS FAIRLY LIGHT. SUB-VFR LIKELY IN SHRA/ISO TSRA THU AFT-FRI AS LOW PRES MOVES ACROSS. WIND SPEED/DIRECTION FORECAST UNCERTAIN WITH LOW MOVING VERY NEAR THE AREA. VFR SHOULD RETURN ALONG W/ NWLY FLOW AROUND 10 KT SAT. && .MARINE... SRLY WINDS WILL CONTINUE ON THE WATERS AND SCA CONDITIONS ARE EXPECTED. WINDS WILL LIKELY SUBSIDE ON THE MIDDLE AND UPPER TIDAL POTOMAC TONIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE SOUTHERN WATERS MAINLY SOUTH OF DRUM POINT THIS AFTERNOON. A COLD FRONT WILL STALL NEAR THE WATERS TUESDAY. SHOWERS AND THUNDERSTORMS ARE POSSIBLE TUESDAY AFTERNOON. SOME STORMS MAY BECOME STRONG AND SMW MAY BE WARRENTED. SUB SCA WINDS WITH DRY CONDITIONS TUE NIGHT-THU MORNING UNDER HIGH PRESSURE. WIND FORECAST OVER THE WATERS IS HIGHLY UNCERTAIN THURSDAY AFT THRU FRIDAY DUE TO LOW PRESSURE PASSING VERY NEAR OR OVERHEAD. HOWEVER...SOME GUSTS IN SOUTHERLY CHANNELING ARE POSSIBLE ACROSS PORTIONS OF THE WATERS...ESPECIALLY IF THE LOW TRACK PASSES FURTHER NORTH. SHOWERS AND ISOLATED THUNDERSTORMS ARE ALSO LIKELY OVER THE WATERS THURSDAY NIGHT INTO FRIDAY. && .TIDES/COASTAL FLOODING... TIDAL ANOMALIES REMAIN BELOW A HALF FOOT THIS AFTERNOON. SOUTHERLY FLOW AHEAD OF AN APPROACHING COLD FRONT WILL ELEVATE TIDAL ANOMALIES THROUGH TONIGHT. WATER LEVELS MAY COME CLOSE TO MINOR FLOODING THRESHOLDS FOR SENSITIVE AREAS AROUND HIGH TIDE TONIGHT...AND AGAIN TUESDAY MORNING. HOWEVER...LATEST GUIDANCE CONTINUES TO KEEP WATER LEVELS BELOW THOSE MINOR THRESHOLDS...WHICH MAKES SENSE SINCE THIS WINDS ARE EXPECTED TO SHIFT WEST OF SOUTH LATER TONIGHT INTO TUESDAY. WATER LEVELS WILL HAVE TO BE MONITORED...SINCE IT WILL BE CLOSE. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR ANZ530-531-538- 539. SMALL CRAFT ADVISORY UNTIL NOON EDT TUESDAY FOR ANZ532>534-537- 540>543. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ535-536. && $$ SYNOPSIS...RCM NEAR TERM...HAS SHORT TERM...RCM LONG TERM...DFH AVIATION...HAS/RCM/DFH MARINE...HAS/RCM/DFH TIDES/COASTAL FLOODING...RCM

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