Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 160553 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 153 AM EDT TUE SEP 16 2014 .SYNOPSIS... A COLD FRONT WILL PASS THROUGH THE REGION OVERNIGHT. HIGH PRESSURE WILL RETURN FOR TUESDAY THROUGH WEDNESDAY BEFORE A REINFORCING COLD FRONT MOVES THROUGH THURSDAY. HIGH PRESSURE WILL BUILD OVERHEAD LATE IN THE WEEK. && .NEAR TERM /THROUGH TODAY/... CLOUD COVER WILL CONTINUE TO INCREASE OVERNIGHT AS AN UPPER DISTURBANCE AND COLD FRONT APPROACH FROM THE WEST. A FEW SHOWERS CANNOT BE RULED OUT AS THIS SYSTEM MOVES THROUGH. HOWEVER...THE DYNAMICS WITH THIS SYSTEM WILL REMAIN MOSTLY TO OUR NORTH AND THE DEEPER MOISTURE WILL BE OFF TO OUR SOUTH. THEREFORE...ANY SHOWERS THAT DO OCCUR WILL BE LIMITED IN COVERAGE AND BRIEF. BEST CHANCES APPEAR TO BE OVER THE POTOMAC HIGHLANDS AND EAST OF THE BLUE RIDGE...ESPECIALLY THE BALTIMORE METRO AREA. THE COLD FRONT WILL MOVE OFF TO OUR EAST TUESDAY AND A NORTHWEST FLOW IS EXPECTED AHEAD OF HIGH PRESSURE BUILDING IN FROM THE MIDWEST. MAX TEMPS MAY ACTUALLY BE A FEW DEGREES WARMER THAN TODAY DUE TO A DEEP MIXING LAYER AND INCREASING AMOUNTS OF SUNSHINE BEHIND THE BOUNDARY. MAX TEMPS ARE FORECAST TO REACH THE MID TO UPPER 70S ACROSS MOST LOCATIONS...BUT COOLER IN THE MOUNTAINS. && .SHORT TERM /TONIGHT THROUGH THURSDAY/... HIGH PRESSURE WILL BUILD OVER NEW ENGLAND TUESDAY NIGHT THROUGH WEDNESDAY BEFORE A REINFORCING COLD FRONT PASSES THROUGH THE AREA LATE WEDNESDAY NIGHT INTO THURSDAY. THE HIGH SHOULD BE CLOSE ENOUGH TUESDAY NIGHT AND WEDNESDAY TO KEEP DRY CONDITIONS IN PLACE...DESPITE AN UPPER-LEVEL TROUGH OVERHEAD. TEMPS WILL BE A FEW DEGREES BELOW CLIMO DURING THIS TIME DUE TO THE UPPER-LEVEL TROUGH. THE REINFORCING COLD FRONT LATE WEDNESDAY NIGHT INTO THURSDAY WILL BE WEAK AND LITTLE MOISTURE WILL BE ASSOCIATED WITH IT. A STRAY SHOWER CANNOT BE RULED OUT...BUT A DRY FORECAST CONTINUES FOR NOW SINCE COVERAGE WOULD BE LIMITED AT BEST. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... A PIECE OF ENERGY WILL TRY TO PUSH ACROSS THE REGION THURSDAY NIGHT BUT BECAUSE OF THE LACK OF MOISTURE...WE HAVE POPS GENERALLY LESS THAN 10 PERCENT. HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE GREAT LAKES AREA LATE THURSDAY NIGHT THROUGH SATURDAY...KEEPING DRY CONDITIONS IN THE REGION. A COLD FRONT WILL APPROACH THE REGION SUNDAY AND SUNDAY NIGHT...BRINGING A SLIGHT CHANCE OF SHOWERS AND PERHAPS A THUNDERSTORM OR TWO. THE MAIN UPPER LEVEL TROUGH OF LOW PRESSURE WILL MOVE THROUGH THE REGION MONDAY...KEEPING A SLIGHT CHANCE OF SHOWERS IN THE PICTURE DURING THIS PERIOD. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... A COLD FRONT WILL PASS THROUGH THE TERMINALS OVERNIGHT. A COUPLE SHOWERS CANNOT BE RULED OUT...BUT MOST AREAS WILL BE DRY. THE BIGGER CONCERN WILL BE CIGS. HV ALREADY DROPPED INTO MVFR ACRS CENTRL VA IN ADVC OF THE FNT. THE CHO TERMINAL IS AFFECTED. WHILE THINK THE AREAL CVRG WL BE INCRSG...DO NOT HV HIGH CONFIDENCE THAT ANY ADDTL TERMINALS WL BE IMPACTED. IAD WL BE ON THE EDGE OF THE CLD SHIELD...AND INTRODUCED A CPL HR BKN030 AT THE BGNG OF THE MRNG PUSH. OTRW...AM PERSERVING VFR ATTM. FURTHER...DO NOT FORSEE IFR. HIGH PRESSURE WILL BRING MORE VFR CONDITIONS TUESDAY THROUGH TUESDAY EVENING. PATCHY BR IS POSSIBLE OVERNIGHT TUESDAY INTO EARLY WEDNESDAY. A COLD FRONT WILL PASS THROUGH THE TERMINALS LATE WEDNESDAY NIGHT INTO THURSDAY...BUT THE BOUNDARY WILL BE WEAK SO IT WILL HAVE A LIMITED IMPACT ON THE TERMINALS. HIGH PRESSURE WILL RETURN FOR FRIDAY AND SATURDAY. && .MARINE... A COLD FRONT WILL PASS THROUGH THE WATERS OVERNIGHT. AHD OF THE FNT...SLY CHANNELING HAS BROUGHT 20-25 KT GUSTS TO TPLM2. POST- FROPA...NWLY FLOW WL MIX BETTER INVOF PRES RISES. MARGINAL CASE OF 20 KT GUSTS. HV ADJUSTED SCA TO BEGIN AT THE CURRENT TIME FOR THE MAIN CHANNEL OF THE BAY AND TANGIER SOUND. THEN...A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL WATERS BEHIND THE FRONT TUESDAY. HIGH PRESSURE WILL BUILD OVER THE WATERS TUESDAY NIGHT THROUGH WEDNESDAY BEFORE A REINFORCING COLD FRONT PASSES THROUGH LATE WEDNESDAY NIGHT INTO THURSDAY. HIGH PRESSURE WILL RETURN FOR LATE IN THE WEEK. && .TIDES/COASTAL FLOODING... SOUTHERLY WINDS HAVE INCREASED ON THE BAY...MARKING A SLOW DECREASE OF HIGH TIDE AT ANNAPOLIS. WE/VE MANAGED TO DROPPED BELOW ADVY CRITERIA...BARELY. TO THE SOUTH...TIDE HAS PASSED AND WATER LEVELS ARE SAFELY BELOW CRITERIA. ALLOWED THE CSTL FLOOD ADVY TO EXPIRE. A COLD FRONT WILL CROSS THE WATERS EARLY THIS MORNING. SHOULD HAVE NW WINDS CAUSING BLOW OUT CONDITIONS BY THE TIME THE NEXT HIGH TIDE ARRIVES. WATER MAY BE SLIGHTLY ELEVATED WRT ASTRO NORMS...BUT NO PROBLEMS ANTICIPATED AT THIS TIME. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 5 PM EDT THIS AFTERNOON FOR ANZ530-531-535>542. SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR ANZ532>534-543. && $$ SYNOPSIS...BJL NEAR TERM...KRW/BJL SHORT TERM...BJL LONG TERM...KLW AVIATION...HTS/BJL MARINE...HTS/BJL TIDES/COASTAL FLOODING...HTS

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