Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 241841 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 241 PM EDT SUN MAY 24 2015 .SYNOPSIS...
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HIGH PRESSURE LOCATED TO THE EAST 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.
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&& .NEAR TERM /THROUGH MONDAY/...
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LATEST SURFACE ANALYSIS SHOWS HIGH PRESSURE ALONG THE COAST OF VIRGINIA...WITH A STORM SYSTEM WELL TO THE WEST IN COLORADO AND ANOTHER WELL TO THE NORTH IN SOUTHEASTERN CANADA. ALOFT...A STRONG RIDGE OF HIGH PRESSURE IS LOCATED OVER FLORIDA WITH A RIDGE AXIS EXTENDING NORTHWEST TOWARDS THE WESTERN GREAT LAKES...AND A CLOSED LOW TO THE WEST OVER THE ROCKIES. A WEST-NORTHWEST FLOW ALOFT IS IN PLACE OVER OUR AREA. 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 STAYING IN THE 50S AND 60S TONIGHT AND RISING WELL INTO THE 80S ON MONDAY. DEW POINTS WHICH ARE IN THE UPPER 40S TO LOWER 50S CURRENTLY WILL RISE INTO THE MID TO UPPER 50S. SOME CUMULUS BUILDUPS OVER THE MOUNTAINS THIS AFTERNOON SHOULD NOT PRODUCE ANY SHOWERS OR THUNDERSTORMS BUT THESE CLOUDS WILL LIKELY ADVECT NORTHEAST INTO THE METRO AREA THIS EVENING AND SKIES MAY CLOUD OVER FOR A TIME AS A RESULT. THE CLOUDS SHOULD BREAK UP/ADVECT NORTHEAST AWAY FROM THE AREA LATER TONIGHT AND 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.
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&& .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
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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.
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&& .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
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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.
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&& .AVIATION /18Z SUNDAY THROUGH FRIDAY/...
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VFR CIGS AND VIS VERY LIKELY THRU THE NEXT 36 HOURS AS HIGH PRESSURE REMAINS IN CONTROL. THERE WILL BE SOME CU THIS AFTERNOON AND EVENING...PROBABLY SOME ON MONDAY BUT LIKELY NOT AS MUCH. THE INCREASING SOUTHWESTERLY FLOW WILL LIKELY PREVENT ANY FOG FORMATION DESPITE INCREASING HUMIDITY...WHILE THE RIDGE ALOFT SHOULD SUPPRESS ANY POTENTIAL SHOWERS OR THUNDERSTORMS. WINDS WILL INCREASE FROM THE SOUTH AND SOUTHWEST ON MONDAY AFTERNOON WITH GUSTS ABOVE 20 KNOTS LIKELY. 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.
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&& .MARINE...
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A FEW GUSTS TO AROUND 20 KNOTS HAVE OCCURRED THIS AFTERNOON SO HAVE KEPT SCA IN PLACE. AS HIGH PRESSURE CONTINUES ITS SLOW MARCH EASTWARD INTO THE ATLANTIC...THE PRESSURE GRADIENT WILL BEGIN TO INCREASE AS WE GET FURTHER FROM ITS CENTER AND THE SOUTH-SOUTHWEST FLOW WILL INCREASE. AFTER POSSIBLY RELAXING A BIT OVERNIGHT...WINDS WILL INCREASE TO SCA LEVELS ACROSS MOST WATERS BY MONDAY AFTERNOON AND HAVE ALSO NOT ALTERED THE SCA IN THIS TIME FRAME EITHER. IT MAY NEED TO BE EXTENDED ACROSS THE REMAINING WATERS IF SOME OF THE PREDICTED GUSTS MATERIALIZE BUT NOT CONFIDENT YET. 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.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON MONDAY TO 6 AM EDT TUESDAY FOR ANZ531>533-538>542. SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR ANZ534-543. SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ532-533-537- 541. SMALL CRAFT ADVISORY FROM NOON MONDAY TO 2 AM EDT TUESDAY FOR ANZ530-537. && $$ SYNOPSIS...RCM NEAR TERM...RCM SHORT TERM...HAS LONG TERM...KLW AVIATION...HAS/RCM/KLW MARINE...HAS/RCM/KLW

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