Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 250114 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 914 PM EDT SUN MAY 24 2015 .SYNOPSIS... HIGH PRESSURE LOCATED OVER THE WESTERN ATLANTIC WILL PROMOTE WARMER AND MORE HUMID WEATHER OVER THE NEXT SEVERAL DAYS. AN APPROACHING COLD FRONT WILL INCREASE THE RISK OF SHOWERS AND THUNDERSTORMS STARTING TUESDAY AND CONTINUING LATER THIS WEEK. && .NEAR TERM /THROUGH MONDAY/... THE CENTER OF SFC HIGH PRESSURE IS LOCATED OFFSHORE EAST OF VA THIS EVENING WITH A LIGHT SOUTHERLY FLOW IN PLACE. A DEEP UPPER LEVEL TROUGH IS LOCATED OVER THE CENTRAL ROCKIES...WITH DOWNSTREAM RIDGE AMPLIFICATION BEGINNING TO TAKE PLACE OVER THE EASTERN CONUS. FOR TONIGHT...EXPECT ONLY SOME PATCHES OF MID AND HIGH LEVEL CLOUDS SPILLING OVER THE RIDGE. DEW POINTS ARE NOW IN THE 50S IN MOST LOCATIONS...WHICH WILL SERVE TO LIMIT TEMPERATURE FALLS. ANY ADDITIONAL FORECAST ADJUSTMENTS WILL LIKELY BE TO CLOUD COVER AND TEMPERATURE...WHERE WE COULD SEE SOME OF THE TYPICAL SHELTERED LOCATIONS DROP A LITTLE LOWER THAN THE CURRENT READINGS. HOWEVER ON THE WHOLE...LOWS IN THE MID 50S TO LOWER 60S ARE EXPECTED...WITH A FEW DEGREES MORE THAN THAT IN THE URBAN CENTERS. OVER THE NEXT 24 HOURS...THE RIDGE ALOFT WILL SHIFT SLIGHTLY EAST WHILE THE RIDGE AXIS WILL SHIFT EAST FASTER...ENDING UP OVER OUR REGION BY LATE MONDAY AFTERNOON. THE HIGH PRESSURE WILL SHIFT A BIT FURTHER EAST BUT ITS INFLUENCE WILL REMAIN AND THE SOUTHWESTERLY FLOW OF MOIST AND WARM AIR ON ITS WESTERN PERIPHERY WILL CONTINUE OVER OUR AREA. THIS WILL PROMOTE A CONTINUED TREND OF WARMER AND MORE HUMID WEATHER...WITH TEMPERATURES RISING WELL INTO THE 80S ON MONDAY. DEW POINTS WILL RISE INTO THE MID TO UPPER 50S. SKIES ON MONDAY SHOULD BE MOSTLY SUNNY WITH HIGH CIRRUS AND A FEW CUMULUS BEING THE MAIN FEATURES. THE RIDGE ALOFT SHOULD SUPPRESS ANY CONVECTION AND KEEP THE WEATHER DRY DESPITE THE INCREASED WARMTH AND HUMIDITY. WINDS WILL BECOME MORE NOTICEABLE AS THE PRESSURE GRADIENT INCREASES...WITH GUSTS ABOVE 20 MPH LIKELY ACROSS THE AREA MONDAY AFTERNOON. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... RETURN FLOW CONTINUES MONDAY NIGHT AS HIGH PRESSURE STAYS OFF THE EAST COAST. THE UPPER LEVEL RIDGE WILL ALSO MOVE EASTWARD WHICH WILL ALLOW MOISTURE TO INCREASE THROUGH THE COLUMN. SHOWERS ARE POSSIBLE IN THE HIGHLANDS EARLY TUESDAY MORNING AS SOME DISSIPATING CONVECTION MOVES INTO THE REGION. SCT SHOWERS AND THUNDERSTORMS ARE EXPECTED TUESDAY AFTERNOON MAINLY ALONG AND WEST OF THE BLUE RIDGE AS THE UPPER LEVEL RIDGE INFLUENCES AREAS CLOSER TO THE EAST COAST. STORM MOTION IS EXPECTED TO BE S-SW ON THE WEST SIDE OF THE RIDGE SO SHOWERS AND THUNDERSTORMS SHOULD STAY NEAR AND WEST OF THE BLUE RIDGE. AS THE RIDGE MOVES EASTWARD TUESDAY NIGHT...SOME SHOWERS WILL BE POSSIBLE ACROSS NRN MD. AT THIS TIME...INSTABILITY AND SHEAR ARE WEAK AND ANY THUNDERSTORMS SHOULD STAY SUB-SVR TUESDAY. WEDNESDAY WILL BE WARMER AND MORE HUMID THAN TUESDAY AS THE UPPER LEVEL RIDGE MOVES FURTHER OFF THE EAST COAST. THIS WILL LEAD TO MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY WEDNESDAY AFTERNOON. A DISTURBANCE IS ALSO EXPECTED TO APPROACH THE REGION WEDNESDAY AS A UPPER LEVEL JET MOVES ACROSS THE EASTERN GREAT LAKES. INSTABILITY AND SHEAR WILL INCREASE BY THE AFTERNOON AND SOME STORMS WILL HAVE THE POTENTIAL TO BE SEVERE. HIGH PWATS WILL ALSO LEAD TO HEAVY RAINFALL. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... A COLD FRONT AT THE SURFACE WILL APPROACH THE REGION FROM THE LOWER GREAT LAKES AND EASTERN OHIO VALLEY WEDNESDAY NIGHT...ALLOWING FOR A COUPLE OF SHOWERS AND THUNDERSTORMS TO LINGER IN PARTS OF THE REGION. LOW TEMPERATURES WILL BE ABOUT 10 TO 15 DEGREES ABOVE AVERAGE. THE COLD FRONT SHOULD PUSH THROUGH THE REGION THURSDAY. ADDITIONAL SHOWERS AND THUNDERSTORMS WILL DEVELOP AHEAD OF AND ALONG THE FRONT IN RESPONSE TO SOME DAYTIME HEATING. HIGH TEMPERATURES WILL APPROACH 90 DEGREES IN MOST PLACES WITH MIDDLE 80S EXPECTED FARTHER TO THE WEST. WE EXPECT THE COLD FRONT TO STALL ACROSS THE EASTERN HALF OF THE REGION THURSDAY NIGHT AND FRIDAY...PROVIDING AMPLE OPPORTUNITY FOR SHOWERS AND THUNDERSTORMS TO DEVELOP AND PRODUCE HEAVY RAINFALL. THERE WILL BE PLENTY OF MOISTURE ALONG THE FRONT AS WELL AS LIGHT AND VARIABLE WINDS IN THE MIDDLE AND UPPER LEVELS OF THE ATMOSPHERE...HENCE ANY ACTIVITY SHOULD BE MOVING SLOWLY FROM WEST TO EAST. LOW TEMPERATURES THURSDAY NIGHT AND HIGH TEMPERATURES FRIDAY COULD STILL BE 7 TO 10 DEGREES ABOVE AVERAGE. THE COLD FRONT IS EXPECTED TO BRIEFLY RETURN NORTHWARD AS A WARM FRONT FRIDAY NIGHT BEFORE A SECOND COLD FRONT...MODERATELY- STRONG... APPROACHES THE REGION SATURDAY. WHILE SHOWER ACTIVITY MAY BE SCATTERED FRIDAY NIGHT...SHOWERS AND THUNDERSTORMS WILL DEVELOP SATURDAY ALONG THE COLD FRONT AND COULD BRING HEAVY RAINFALL AND GUSTY WINDS. LOW TEMPERATURES FRIDAY NIGHT AND HIGH TEMPERATURES SATURDAY COULD BE 10 DEGREES ABOVE NORMAL...REACHING THE UPPER 60S AND NEAR 90...RESPECTIVELY. THE COLD FRONT SHOULD SLOWLY PUSH THROUGH THE REGION SATURDAY NIGHT INTO SUNDAY. SHOWERS AND THUNDERSTORMS WILL STILL LINGER ALONG THE COLD FRONT SATURDAY NIGHT INTO SUNDAY...BUT BECOME MORE ISOLATED IN THE POTOMAC HIGHLANDS LATER IN THE WEEKEND. LOWS SATURDAY NIGHT AND HIGHS SUNDAY WILL STILL BE ABOVE AVERAGE. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... HIGH CONFIDENCE IN VFR CONDITIONS THROUGH MONDAY NIGHT AS OFFSHORE HIGH PRESSURE CONTROLS THE WEATHER. DESPITE INCREASED DEW POINTS...THINK THE LOW LEVELS OF THE ATMOSPHERE ARE STILL TOO DRY FOR ANY FOG FORMATION TONIGHT. ALSO A LIGHT SOUTHERLY WIND MAY STAY IN PLACE. WINDS BETWEEN 180-230 DEG WILL INCREASE DURING THE DAYLIGHT HOURS...WITH GUSTS UP TO 20-25 KT. THESE GUSTS WILL SUBSIDE WITH SUNSET. CU SHOULD BE FEW AND FAR BETWEEN INVOF TAF SITES MONDAY...WITH BASES OF 5-6 KFT IF THEY DO FORM. BY TUESDAY AFTERNOON -SHRA/VCTS POSSIBLE MAINLY AT MRB/CHO. -SHRA/TSRA ARE LIKELY AT ALL THE TERMINALS WEDNESDAY. SOME STORMS MAY PRODUCE GUSTY WINDS AND HEAVY RAINFALL RESULTING IN SUB-VFR CONDITIONS. MVFR TO IFR CONDITIONS POSSIBLE AT ALL TERMINALS WEDNESDAY NIGHT THROUGH THURSDAY WITH SHOWERS AND THUNDERSTORMS. WINDS GENERALLY SOUTHWEST 5 TO 10 KNOTS WITH A FEW HIGHER GUSTS. && .MARINE... HIGH PRESSURE OFFSHORE EAST OF VA IS PROMOTING GENERALLY SOUTHERLY WINDS OVER THE WATERS. GUSTS TO 20 KT HAVE BEEN CONFINED TO THE SOUTHERN PORTION OF THE MD BAY...AND HAVE RELAXED IN THE PAST HOUR. HAVE A SCA CONTINUING IN THIS AREA THROUGH THE NIGHT...BUT IF THE TREND CONTINUES...MAY BE ABLE TO CANCEL AND SQUEEZE IN A PERIOD OF NO HEADLINES THROUGH EARLY MORNING. HOWEVER THE GRADIENT WILL STRENGTHEN MONDAY AND ALLOW S/SW WINDS TO COMMONLY GUST TO 20-25 KT. A SCA NOW GOES INTO EFFECT FOR ALL WATERS AT 10 AM. THE SCA IS WHITTLED BACK TO PORTIONS OF THE BAY LATE MONDAY NIGHT WHERE SOUTHERLY CHANNELING MAY CONTINUE. NO PRECIPITATION IS EXPECTED THROUGH MONDAY NIGHT. GUSTY S WINDS WILL CONTINUE ON THE WATERS TUESDAY AND WEDNESDAY AND SCA MAY BE NEEDED OR EXTENDED. SHOWERS AND THUNDERSTORMS POSSIBLE WEDNESDAY AND SOME MAY PRODUCE GUSTY WINDS AND LOW VSBYS ON THE WATERS. SMALL CRAFT ADVISORY CONDITIONS POSSIBLE WEDNESDAY NIGHT THROUGH THURSDAY...PRIMARILY FOR THE MAIN STEM CHESAPEAKE BAY. && .CLIMATE... UNUSUALLY HOT TEMPERATURES FOR THIS EARLY IN THE YEAR ARE FORECAST DURING MUCH OF THE UPCOMING WEEK. BELOW IS A LIST OF RECORD DAILY WARM TEMPERATURES FOR THE UPCOMING WEEK. .......RECORD WARM TEMPERATURES FOR DCA........ DATE...RECORD HIGH...........RECORD HIGH MIN... 5/25...94 (1880).............71 (2012)......... 5/26...96 (1880).............74 (1991)......... 5/27...95 (1965/1914/1880)...75 (1991)......... 5/28...97 (1941).............75 (1991)......... 5/29...97 (1991/1969)........74 (1991)......... 5/30...98 (1991).............74 (1991)......... .......RECORD WARM TEMPERATURES FOR BWI........ DATE...RECORD HIGH...........RECORD HIGH MIN... 5/25...94 (1991).............70 (1936)......... 5/26...94 (1914).............74 (1880)......... 5/27...95 (1965/1941)........75 (1880)......... 5/28...97 (1941).............78 (1941)......... 5/29...97 (1969).............71 (1908)......... 5/30...98* (2011/1991).......72 (1895)......... *ALSO HIGHEST OBSERVED MAY MONTHLY TEMPERATURE .......RECORD WARM TEMPERATURES FOR IAD........ DATE...RECORD HIGH...........RECORD HIGH MIN... 5/25...92 (1991).............67 (2004)......... 5/26...92 (2007).............70 (1991)......... 5/27...92 (2010/1965)........69 (2008/1991).... 5/28...90 (2012/1991)........70 (1991)......... 5/29...97* (1969)............69 (2012)......... 5/30...95 (2006/1991/1987)...70 (2011)......... *ALSO HIGHEST OBSERVED MAY MONTHLY TEMPERATURE BELOW IS THE LONGEST STRETCH OF CONSECUTIVE DAYS AT OR ABOVE 90 F DURING THE MONTH OF MAY. DCA...7 DAYS (05/25-05/31/1991) BWI...7 DAYS (05/25-05/31/1991) IAD...7 DAYS (05/25-05/31/1991) && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 AM MONDAY TO 6 AM EDT TUESDAY FOR ANZ531-538>540-542. SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR ANZ532>534-541- 543. SMALL CRAFT ADVISORY FROM 10 AM MONDAY TO 2 AM EDT TUESDAY FOR ANZ530-535-536. SMALL CRAFT ADVISORY UNTIL 2 AM EDT TUESDAY FOR ANZ537. && $$ SYNOPSIS...RCM NEAR TERM...ADS/RCM SHORT TERM...HAS LONG TERM...KLW AVIATION...ADS/HAS/KLW MARINE...ADS/HAS/KLW CLIMATE...DFH

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