Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 282344 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 644 PM EST FRI NOV 28 2014 .SYNOPSIS... HIGH PRESSURE WILL MOVE OVERHEAD THIS EVENING BEFORE PUSHING OFF TO OUR EAST LATE TONIGHT. A WARM FRONT WILL LIFT TO THE NORTH LATE TONIGHT AND A SOUTHERLY FLOW WILL USHER IN MILDER CONDITIONS FOR THE WEEKEND. A COLD FRONT WILL PASS THROUGH THE AREA MONDAY AND WEAK LOW PRESSURE MAY IMPACT THE AREA TUESDAY INTO WEDNESDAY. && .NEAR TERM /THROUGH SATURDAY/... SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD OVERHEAD THROUGH THIS EVENING. A STRATOCU DECK ALONG WITH A FEW SNOW SHOWERS ALONG AND WEST OF THE ALLEGHENY FRONT WILL DISSIPATE LATE AS HIGH PRESSURE BUILDS OVERHEAD. HOWEVER...MORE HIGH AND MID-LEVEL CLOUDS WILL QUICKLY BUILD OVERHEAD THIS EVENING AS SHORTWAVE ENERGY PASSES THROUGH IN THE NORTHWEST FLOW ALOFT. THE HIGH WILL MOVE OFF TO THE EAST LATE TONIGHT AND A WEAK WARM FRONT WILL LIFT NORTH THROUGH THE REGION DURING THIS TIME. AT THE SAME TIME...SHORTWAVE ENERGY WILL BE PASSING THROUGH WITH MOST OF THE ENERGY REMAINING TO OUR NORTH. WARM ADVECTION AHEAD OF THE WARM FRONT ALONG WITH THE SHORTWAVE ENERGY MAY BE ENOUGH TO OVERCOME THE DRY AIR IN PLACE FOR A FEW FLURRIES AND PERHAPS A PERIOD OF LIGHT SNOW FOR LOCATIONS NEAR THE MASON-DIXON LINE. AS OF NOW...IT APPEARS THAT WITH THE BEST FORCING REMAINING TO OUR NORTH THE ACCUMULATING SNOW IS MOST LIKELY TO REMAIN TO OUR NORTH. HOWEVER...A WHITENING OF THE GROUND CANNOT BE RULED OUT LATE TONIGHT INTO EARLY SATURDAY MORNING FOR LOCATIONS NEAR THE MASON- DIXON LINE. MIN TEMPS WILL BE COLD...RANGING FROM THE TEENS ALONG THE ALLEGHENY FRONT TO THE LOWER 30S IN DOWNTOWN WASHINGTON AND BALTIMORE. THE WARM FRONT WILL CONTINUE TO LIFT AWAY FROM OUR REGION SATURDAY TO OUR NORTH. SHORTWAVE ENERGY WILL ALSO BE FOCUSED TO OUR NORTH AS WELL. THEREFORE...ANY LIGHT SNOW OR FLURRIES EARLY WILL DISSIPATE. A SOUTHERLY FLOW BEHIND THE BOUNDARY AND DEPARTING HIGH PRESSURE OVER THE ATLANTIC OCEAN WILL COMBINE WITH SOME SUNSHINE TO BRING MILDER CONDITIONS COMPARED TO RECENT DAYS. HOWEVER...THERE WILL BE BROKEN DECK OF MID-LEVEL CLOUDS OVERHEAD KEEPING MAX TEMPS BELOW CLIMO. MAX TEMPS ARE FORECAST TO RANGE FROM NEAR 40 ALONG THE MASON-DIXON LINE TO THE UPPER 40S IN PORTIONS OF CENTRAL VIRGINIA. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... BROAD RIDGING OVER THE ERN CONUS SATURDAY NIGHT THROUGH SUNDAY NIGHT WITH A WARMING TREND BRINGING TEMPERATURES ABOVE NORMAL. WARM AIR ADVECTION WILL SET UP A PERSISTENT CLOUD LAYER IN THE LOWER MID- LEVEL INVERSION. ALMOST ALL PRECIP IS EXPECTED TO BE OVER THE ERN MIDWEST TO THE ALLEGHENY FRONT. FORCING WEST OF THE AREA TURNS TO CONVERGENCE LATE SUNDAY AS A COLD FRONT APPROACHES FROM THE GREAT LAKES. PRECIP EXPECTED TO BE RAIN THROUGH THE EVENT AS THERMAL PROFILES EXCEED FREEZING BELOW 800MB OR SO. DRY EAST OF THE ALLEGHENY FRONT WITH SWLY/SLY FLOW 10 TO 15 MPH MAINTAINED THROUGH SATURDAY NIGHT IN DECENT PRESSURE GRADIENT. LAST DAY OF NOVEMBER WILL HAVE SWLY FLOW AND ABOVE NORMAL TEMPERATURES MID TO UPR 50S FOR MOST INLAND AREAS...LOW 60S POSSIBLE IN THE SWRN HALF OF THE CWA WHERE CLOUD COVER LOOKS TO BE MORE SCATTERED. COLD FRONT APPROACHES FROM THE WEST SUNDAY NIGHT. && .LONG TERM /MONDAY THROUGH FRIDAY/... A COLD FRONT WILL SINK THROUGH THE AREA LATE MONDAY. THERE IS NOT A LOT OF MOISTURE WITH THIS FRONT AND MOST MODELS ONLY HAVE SCATTERED SHOWERS. AS SUCH HAVE CAPPED POPS AT CHANCE MONDAY INTO MONDAY NIGHT. ANY RESIDUAL MOISTURE COULD RESULT IN UPSLOPE SNOW SHOWERS ALONG THE WESTERN RIDGES OVERNIGHT MONDAY NIGHT AS THE COLUMN COOLS. STRONG AND COLD HIGH PRESSURE MOVES BY TO THE NORTH TUESDAY INTO TUESDAY NIGHT. SOUTHERLY RETURN FLOW/ISENTROPIC LIFT SETS UP AS THE AFOREMENTIONED FRONT /WHICH WILL HAVE STALLED TO THE SOUTH/ RETURNS NORTH AS A WARM FRONT. AT LEAST LIGHT PRECIPITATION SEEMS PLAUSIBLE IN THIS SETUP SO HAVE CHANCE POPS TUESDAY NIGHT AS WELL. KEPT IT AS A GENERIC RAIN/SNOW MIX BUT OTHER PTYPES MAY COME INTO PLAY AS WELL AS STRONG COLD AIR DAMMING SIGNATURE IS EVIDENT WHILE WARM AIR OVERRUNS THE COLD AIR AT THE SURFACE. WARMING TREND CONTINUES WEDNESDAY INTO THURSDAY AS A COLD FRONT APPROACHES FROM THE WEST BRINGING WITH IT ANOTHER CHANCE OF RAIN SHOWERS LATER NEXT WEEK. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY. HOWEVER...A FEW FLURRIES CANNOT BE RULED OUT ACROSS THE NORTHERN TERMINALS LATE TONIGHT INTO EARLY SATURDAY. MVFR VSBYS ARE POSSIBLE IN ANY FLURRIES. GUSTS AROUND 15 TO 20 KNOTS ARE EXPECTED SATURDAY AFTERNOON. BKN LOWER MID-LEVEL CIGS PREVAIL SATURDAY NIGHT THROUGH SUNDAY NIGHT...PERIODIC MVFR POSSIBLE...VFR VSBYS WITH DRY WEATHER. SWLY/SLY 10-15 KT THROUGH SATURDAY NIGHT...CONTINUING THROUGH SUNDAY BEFORE SLACKING SUNDAY NIGHT. SPOTTY SUB-VFR POSSIBLE MON EVE IN ISO SHWRS. SW FLOW AOB 10 KTS MON BECOMES NW AROUND 10-20 KTS GUSTING TO 25 KTS FOLLOWING FROPA MON EVE. VFR TUE W/ WIND TURNING N 10-20 KTS...THEN LIGHT AND VARIABLE WIND TUE NIGHT INTO EARLY WED W/ SUB-VFR LIKELY IN LOW CIGS/LIGHT PRECIP. && .MARINE... WINDS HAD DIMINISHED LESS THAN 15 KTS ACROSS ALL WATERS AS OF THE 23Z OB. THEREFORE...SCA WAS ALLOWED TO EXPIRE...WITH NO MARINE HEADLINES EXPECTED THE REMAINDER OF TONIGHT AS HIGH PRESSURE BUILDS OVERHEAD. HIGH PRESSURE WILL MOVE OFF TO THE EAST SATURDAY AND SOUTHERLY WINDS WILL INCREASE. A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE WATERS SATURDAY AFTERNOON. SWLY FLOW BECOMES MORE SLY SATURDAY NIGHT WITH SCA FOR UP TO 25 KT CHANNELING UP THE MAIN PORTION OF THE BAY AND 20 KT FOR EASTERN TRIBUTARIES AND LOWER TIDAL POTOMAC. 20 KT WINDS LIKELY CONTINUE INTO SUNDAY BEFORE THE PRESSURE GRADIENT SLACKENS. SOUTHWEST WIND BECOME NORTHWEST AND INCREASE TO 15-20 KTS W/ GUSTS TO 25 KTS MONDAY AS A COLD FRONT SINKS THROUGH THE WATERS. NORTHERLY CHANNELING COULD RESULT IN A CONTINUATION OF WIND GUSTS TO SMALL CRAFT ADVISORY LEVELS FOR A TIME TUESDAY OVER PARTS OF THE WATERS. WINDS BECOME LIGHT AND VARIABLE TUESDAY NIGHT INTO WEDNESDAY AS A WARM FRONT SLOWLY LIFTS ACROSS THE AREA. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON SATURDAY TO 6 AM EST SUNDAY FOR ANZ530>534-537-539>541-543. SMALL CRAFT ADVISORY FROM NOON TO 6 PM EST SATURDAY FOR ANZ535- 536-538-542. && $$ SYNOPSIS...BJL NEAR TERM...BJL SHORT TERM...BAJ LONG TERM...DFH AVIATION...BAJ/BJL/DFH MARINE...BAJ/BJL/DFH

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