Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 301906 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 306 PM EDT THU JUL 30 2015 .SYNOPSIS...
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A COLD FRONT MOVES THROUGH LATE TODAY...WITH HIGH PRESSURE BUILDING IN THE WAKE. A COLD FRONT MAY MOVE THROUGH OVER THE WEEKEND...WITH THE HIGH PRESSURE RETURNING TO START THE WEEK BEFORE THE NEXT COLD FRONT MOVES THROUGH THE MIDDLE OF NEXT WEEK.
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&& .NEAR TERM /THROUGH FRIDAY NIGHT/...
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PRE-FRONTAL LINE OF THUNDERSTORMS EXTENDING FROM CECIL COUNTY SOUTHWEST INTO CENTRAL VA AS OF 1830Z REFLECTIVITY. SPC MESOANALYSIS SHOWING SBCAPE ANYWHERE FROM 1500-2500 J/KG EAST OF THE BLUE RIDGE AFTR A DAY OF TEMPS REACHING THE UPPER 80S AND DEW PTS HOVERING IN THE MID 70S. EXPECTING THIS LINE TO HOLD TOGETHER AS IT MOVES INTO A VERY UNSTABLE AIR MASS...THOUGH WITH LACK OF SHEAR AND WEAK LAPSE RATES ANY FURTHER SVR WX LOOKS TO BE MINIMAL. SFC ANALYSIS SHOWING COLD FRONT OVER WESTERN VA/EASTERN WV AND WILL SWING THROUGH LATE THIS AFTN INTO THIS EVENING. MODELS SUGGESTING ANOTHER ROUND OF PCPN WILL BE PSBL ALONG THE FRONT...ESP OVER THE PIEDMONT AND SOUTH AS THIS AREA HAS YET TO BE TAPPED. THE TIME FRAME FOR THIS LOOKS TO BE 21-02Z. THE FRONT THEN PUSHES THRU...WITH CLEARING IN THE WAKE. TEMPS MILDLY DECREASE...WITH THE FRONTAL PASSAGE BEING MORE NOTICABLE IN THE DEW PTS AS THEY DROP INTO THE 50S AND 60S. HIGH PRESSURE BUILDS IN...KEEPING THE AREA DRY THEN THRU FRI NIGHT. LOWS TONIGHT NEAR NORMAL. PLENTY OF WARMING UNDER MOSTLY SUNNY SKIES AND DOWNSLOPING FROM WLY FLOW ON FRI COULD PUSH TEMPS INTO THE UPPER 80S...TOUCHING 90 IN THE DC AND BALTIMORE METRO AREAS. HOWEVER...WITH THE LOWER DEW PTS...HEAT ADVISORY CRITERIA IS NOT EXPECTED TO BE REACHED.
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&& .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
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THE MID ATLANTIC REMAINS UNDER A BROAD UPPER LVL TROUGH AND ON THE WESTERN PERIPHERY OF HIGH PRESSURE AT THE SFC BY SAT MORNING. 12 MODEL SUITE NOW SUGGESTING THAT A COLD FRONT WILL MOVE THRU SOMETIME LATE SAT. HOWEVER...ANY UPPER LVL FORCING WITH SHORTWAVE ENERGY LOOKS TO STILL REMAIN MAINLY NORTH OF THE AREA. WITH A FAIRLY DRY AIR MASS IN PLACE...PWATS BELOW 1.0 INCHES...EXPECTING THE FRONTAL PASSAGE TO BE MAINLY DRY...WITH NOTHING MORE THAN A WIND SHIFT. HAVE KEPT THE LOW END SLIGHT CHC POPS FOR JUST THE FAR WEST AREAS IN CASE OF TERRAIN DRIVEN CONVECTION. ANYTHING THAT DOES FORM WILL BE GONE BY SAT EVENING. THE HIGH PUSHES EAST SAT NIGHT THRU SUN NIGHT...BRINGING DRY AND QUIET WX TO THE AREA. HIGHS HOVERING IN THE LOW TO UPPER 80S WITH OVERNIGHT LOWS GENERALLY IN THE 60S.
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&& .LONG TERM /MONDAY THROUGH THURSDAY/...
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HIGH PRESS DOMINATES CONDITIONS SUN NIGHT INTO MONDAY. LATE MON INTO TUE SWLY FLOW ADVECTS MOISTURE OVER OUR REGION INCREASING THE CHANCE OF SHOWERS AND TSTMS. A CDFNT APPROACHES TUE NIGHT INTO WED AND STALLS AROUND OUR AREA THROUGH THU... BRINGING ADDITIONAL CHANCE OF SHOWERS AND TSTMS FOR THIS PERIOD. TEMPS WILL NEAR NORMAL SUN AND GRADUALLY INCREASING INTO HE LOW 90S FOR WED.
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&& .AVIATION /19Z THURSDAY THROUGH TUESDAY/...
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MAINLY VFR CONDITIONS FOR THE TAF PERIOD. TSTMS WILL MOVE THRU THE TAF SITES EAST OF I-95 THRU 21Z. THESE STORMS COULD RESULT IN GUSTY...VRB WINDS AND HEAVY RAIN WHICH COULD REDUCE VIS TO IFR. SLY WINDS LATE THIS AFTN WILL SHIFT THIS EVENING TO THE NW BEHIND A COLD FRONT MVG THRU. WNW FLOW WILL CONTINUE THRU FRI. VFR CONDITIONS FRI NIGHT INTO NEXT MONDAY.
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&& .MARINE...
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OCNL GUSTS OUTSIDE OF CONVECTION CURRENTLY REACHING SCA CRITERIA SO WILL LET THE SCA CONTINUE THRU THIS EVENING. SLY FLOW WILL BECOME NWLY DURING THE EVENING HOURS...WITH PSBL GUSTS TO 20 KTS AS THE FRONT MOVES THRU. OTHERWISE...SUB-SCA CONDITIONS THEN THE REMAINDER OF THE NIGHT THRU FRI. SUB-SCA CONDITIONS WILL REMAIN IN PLACE FOR THE WEEKEND INTO MONDAY WITH HIGH PRESSURE.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ530>543.
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&& $$ SYNOPSIS...SEARS NEAR TERM...SEARS SHORT TERM...SEARS LONG TERM...IMR AVIATION...SEARS/IMR MARINE...SEARS/IMR

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