Area Forecast Discussion
Issued by NWS Sterling, VA

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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 180208 AAA AFDLWX AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1008 PM EDT SUN MAY 17 2015 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER THE ATLANTIC OCEAN TONIGHT. A BACK DOOR COLD FRONT WILL SLIDE SOUTH INTO THE AREA MONDAY BEFORE DISSIPATING. A STRONGER COLD FRONT WILL MOVE IN FROM THE WEST TUESDAY. COOL AND DRY HIGH PRESSURE WILL FOLLOW FROM THE MIDDLE OF NEXT WEEK UNTIL THE EARLY PART OF NEXT WEEKEND. && .NEAR TERM /THROUGH MONDAY/... PLENTY OF LOW-LEVEL MOISTURE REMAINS IN PLACE...AND WITH LIGHT WINDS ALONG WITH BREAKS IN THE CLOUD COVER...AREAS OF FOG ARE EXPECTED LATE TONIGHT. SOME FOG MAY BE DENSE. WILL CONTINUE TO MONITOR VISIBILITIES OVERNIGHT. HIGH PRESSURE WILL REMAIN OVER THE ATLANTIC TONIGHT WHILE AN UPPER-LEVEL RIDGE REMAINS OVER THE SOUTHEASTERN CONUS. THE UPPER- LEVEL RIDGE AXIS WILL EXTEND NORTH INTO OUR AREA. A SOUTHWEST FLOW AROUND THE HIGH HAS ALLOWED FOR PLENTY OF WARM AND MOIST AIR TO MOVE INTO THE AREA. CONVECTION THIS AFTERNOON WAS NOT AS WIDESPREAD AS SATURDAY DUE MORE CLOUD COVER AND EVEN LESS SHEAR. THE LACK OF THUNDERSTORMS THIS AFTERNOON HAS LED TO MORE INSTABILITY THIS EVENING. LATEST MESOANALYSIS STILL SHOWS 1000 TO 1500 MLCAPE WITH LITTLE IN THE WAY OF A CAPPING INVERSION. CONVECTION THAT DEVELOPED OVER THE HIGHER TERRAIN TO OUR SOUTH AND WEST HAS SPREAD NORTHEAST INTO NORTHERN VIRGINIA. CONVECTION MAY CONTINUE TO FEED OFF ITSELF THIS EVENING DUE TO THE WEAK INVERSION. THEREFORE...WILL CONTINUE WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FOR MOST AREAS THIS EVENING. COVERAGE IS EXPECTED TO DISSIPATE OVERNIGHT AS INSTABILITY LOWERS DUE TO THE LOSS OF DAYTIME HEATING. A BACK DOOR BOUNDARY WILL MOVE INTO EASTERN PORTIONS OF THE CWA LATER MONDAY. MORE WARM AND HUMID CONDITIONS ARE EXPECTED AHEAD OF THIS SYSTEM. THE BACKDOOR BOUNDARY AND A SURFACE TROUGH WILL ACT AS LIFTING MECHANISMS FOR MORE SHOWERS AND THUNDERSTORMS...MAINLY DURING THE AFTERNOON AND EVENING. COVERAGE OF CONVECTION IS EXPECTED TO BE HIGHER THAN SUNDAY DO TO LESS MID- LEVEL CLOUDS AND STRONGER FORCING FROM THE SURFACE TROUGH AND APPROACHING BACKDOOR BOUNDARY. SOME OF THE STORMS WILL BE CAPABLE OF PRODUCING SMALL HAIL...GUSTY WINDS AND HEAVY DOWNPOURS. AFTERNOON HIGH TEMPERATURES WILL LIKELY REACH THE MIDDLE TO UPPER 80S. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... PIECES OF UPPER LEVEL ENERGY WILL RIDE AROUND THE NORTHERN PERIPHERY OF THE WEAKENING RIDGE OF HIGH PRESSURE OVER THE CAROLINAS. SHOWERS AND A COUPLE OF THUNDERSTORMS WILL AFFECT THE REGION MONDAY NIGHT AS A FRONT BECOMES STALLED ACROSS THE REGION. LOW TEMPERATURES MONDAY NIGHT WILL BE ABOUT 10 TO 15 DEGREES ABOVE NORMAL. A TROUGH OF LOW PRESSURE WILL SLIDE ACROSS THE LOWER GREAT LAKES TUESDAY AND TUESDAY NIGHT...GENERATING ONE FINAL ROUND OF SHOWERS AND THUNDERSTORMS TUESDAY AFTERNOON AND EVENING BEFORE COOLER AND DRIER AIR PUSHES INTO THE REGION TUESDAY OVERNIGHT. HIGHS TUESDAY WILL BE 10 DEGREES ABOVE NORMAL. LOWS TUESDAY NIGHT WILL BE COOLER THAN PREVIOUS NIGHTS. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... DRY CONDITIONS WILL PERSIST WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE BUILDS IN ACROSS THE REGION. HIGHS WILL BE IN THE LOWER TO MIDDLE 70S WEDNESDAY WITH LOWS IN THE MIDDLE 40S IN THE POTOMAC HIGHLANDS TO LOWER 50S ALONG THE TIDAL POTOMAC. ONCE THE HIGH PRESSURE MOVES TO THE COAST THURSDAY INTO THURSDAY NIGHT...A SOUTHERLY RETURN FLOW WILL DEVELOP AND USHER BACK IN MORE HUMID AIR FROM THE SOUTH. THERE IS A SLIGHT CHANCE OF RAIN SHOWERS THURSDAY WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS THURSDAY NIGHT...MAINLY IN THE SOUTH AND WEST...AS WEAK UPPER LEVEL ENERGY PIVOTS ACROSS THE EASTERN OHIO VALLEY. HIGH PRESSURE RETURNS FRIDAY THROUGH SUNDAY...BRINGING DRIER CONDITIONS TO THE REGION WITH HIGHS IN THE MIDDLE TO UPPER 70S EACH DAY. ENERGY ARRIVING FROM THE WEST SUNDAY NIGHT INTO EARLY NEXT WEEK COULD BRING OUR NEXT ROUND OF SHOWERS AND INTENSE THUNDERSTORMS. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... SCATTERED SHOWERS AND AN ISOLATED THUNDERSTORM ARE EXPECTED THROUGH THIS EVENING. COVERAGE WITH CONVECTION SHOULD DISSIPATE OVERNIGHT. AREAS OF BR/FOG ARE EXPECTED OVERNIGHT WITH MVFR/IFR CONDITIONS LIKELY. THE BEST CHANCE FOR IFR CONDITIONS WILL BE ACROSS THE WESTERN TERMINALS. AND FOG WILL BURN OFF MONDAY MORNING. ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED MONDAY AFTERNOON AND EVENING. MAINLY MVFR CONDITIONS MONDAY NIGHT AND TUESDAY WITH EXCEPTION TO IFR OR LIFR CONDITIONS IN SHOWER AND THUNDERSTORM ACTIVITY EACH PERIOD. WINDS WILL BE LIGHT AND VARIABLE EXCEPT IN ANY GUSTY THUNDERSTORMS. VFR CONDITIONS TUESDAY NIGHT AND WEDNESDAY WITH HIGH PRESSURE BUILDING INTO THE REGION. WINDS WILL SHIFT TO THE NORTHWEST AND INCREASE TUESDAY NIGHT INTO WEDNESDAY MORNING. MAINLY VFR OR MVFR CONDITIONS WEDNESDAY NIGHT AND THURSDAY WITH A CHANCE OF IFR CONDITIONS NEAR CHO TERMINAL WITH ANY PASSING SHOWER OR THUNDERSTORM ACTIVITY. && .MARINE... WINDS WILL LIKELY REMAIN BELOW SCA CRITERIA THROUGH MONDAY. SHOWERS AND THUNDERSTORMS WILL IMPACT THE WATERS WHICH MAY REQUIRE THE ISSUANCE OF SMWS...MAINLY MONDAY AFTERNOON AND EVENING. NO MARINE HAZARDS MONDAY NIGHT THROUGH TUESDAY. SMALL CRAFT ADVISORY CONDITIONS POSSIBLE TUESDAY NIGHT INTO EARLY WEDNESDAY. NO MARINE HAZARDS MIDDAY WEDNESDAY THROUGH THURSDAY. && .CLIMATE... UNUSUALLY WARM WEATHER IS FORECAST THE NEXT FEW NIGHTS. BELOW IS A LIST OF RECORD HIGH MINIMUM TEMPERATURES FOR MAY 17TH...18TH AND 19TH. SITE...MAY 17TH.........MAY 18TH.........MAY 19TH......... DCA....69 (1974)........68 (1995*).......70 (1986/1962)... BWI....68 (1946/1911)...68 (1900/1896)...75 (1877)........ IAD....65 (1974)........66 (1995)........66 (1969)........ *ALSO IN 1953...1943 AND 1900. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...CAS NEAR TERM...BJL/KRW SHORT TERM...KRW LONG TERM...KLW AVIATION...BJL/KLW/KRW MARINE...BJL/KLW/KRW CLIMATE...

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