Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 010746 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 346 AM EDT SAT AUG 1 2015 .SYNOPSIS... A WEAKENING COLD FRONT WILL CROSS THE REGION TODAY. HIGH PRESSURE WILL REBUILD OVERHEAD SUNDAY BEFORE MOVING OFF THE COAST EARLY NEXT WEEK. ANOTHER COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY AND THEN IT WILL STALL OUT NEARBY FOR TUESDAY AND WEDNESDAY. LOW PRESSURE MAY RIDE ALONG THE BOUNDARY...PASSING THROUGH OUR AREA THURSDAY AND THE BOUNDARY WILL SHIFT TO THE SOUTH LATE IN THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... WEAK COLD FRONT LOCATED OVER THE MIDWEST WILL PUSH THROUGH THE REGION LATER TODAY. THE FRONT WILL BRING A WEAK WIND SHIFT TO THE W-NW AROUND MIDDAY BUT NO PRECIPITATION IS EXPECTED. AFTERNOON HIGH TEMPERATURES ARE EXPECTED TO TOP OUT IN THE UPPER 70S TO LOW 80S WEST OF THE BLUE RIDGE...MID TO UPPER 80S EAST OF THE BLUE RIDGE...EXCEPT NEAR 90 OVER THE BALTIMORE AND WASHINGTON DC METRO AREAS. OVERNIGHT LOWS WILL DIP BACK INTO THE 60S...EXCEPT LOW 70S IN THE METRO AREAS. SOME PATCHY FOG COULD DEVELOP OVERNIGHT. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... HIGH PRESSURE WILL BUILD OVER THE REGION ON SUNDAY. AFTERNOON HIGH TEMPERATURES WILL LIKELY REACH INTO THE UPPER 80S TO THE LOWER 90S...WARMEST OVER THE DC/BALTIMORE METRO AREAS. HIGH PRESSURE WILL WEAKEN OVER THE AREA SUNDAY NIGHT...BUT IT SHOULD CONTINUE TO BRING DRY CONDITIONS TO THE AREA. MIN TEMPS WILL RANGE FROM THE 50S AND 60S IN THE POTOMAC HIGHLANDS TO THE LOWER AND MIDDLE 70S IN DOWNTOWN WASHINGTON/BALTIMORE. && .LONG TERM /MONDAY THROUGH FRIDAY/... A WEAK COLD FRONT WILL PASS THROUGH THE AREA MONDAY AFTERNOON AND EVENING. HOWEVER...IT WILL ACTUALLY TURN OUT HOTTER MONDAY DUE TO PLENTY OF SUNSHINE AND A DOWNSLOPING WESTERLY COMPONENT TO THE SURFACE FLOW. MAX TEMPS WILL BE IN THE LOWER TO MIDDLE 90S ACROSS MOST AREAS. DEWPOINTS SHOULD REMAIN IN THE 50S AND LOWER 60S FOR MOST AREAS...KEEPING RELATIVE HUMIDITY DOWN WHICH SHOULD ALLOW FOR HEAT INDICES TO BE NEAR THE AIR TEMPERATURES. AN ISOLATED SHOWER OR THUNDERSTORM CANNOT BE RULED OUT...BUT MOST AREAS WILL TURN OUT DRY. WEAK HIGH PRESSURE WILL BUILD OVERHEAD MONDAY NIGHT...BRINGING DRY CONDITIONS. AN UPPER-LEVEL LOW WILL CONTINUE TO SPIN NEAR THE HUDSON BAY TUESDAY THROUGH FRIDAY WHILE AN UPPER-LEVEL RIDGE REMAINS CENTERED ACROSS THE SOUTH-CENTRAL CONUS ACROSS FLORIDA INTO THE ATLANTIC OCEAN. A ZONAL FLOW IS EXPECTED OVERHEAD DURING THIS TIME. A NEARLY STATIONARY BOUNDARY WILL SEPARATE THE TWO AIRMASSES BETWEEN COOL CONDITIONS ACROSS THE NORTHEASTERN CONUS AND HOT AND HUMID CONDITIONS ACROSS THE SOUTHEASTERN CONUS. THERE IS STILL SOME UNCERTAINTY AS TO WHERE EXACTLY THIS BOUNDARY WILL SETUP...BUT LATEST GUIDANCE KEEPS IT NEAR THE MASON-DIXON LINE THROUGH THE MIDDLE PORTION OF NEXT WEEK BEFORE THE BOUNDARY POSSIBLY SLIDING SOUTH LATE IN THE WEEK. IF THE BOUNDARY REMAINS TO OUR NORTH...THEN UNSETTLED CONDITIONS ARE POSSIBLE DUE TO THE WARM AND HUMID CONDITIONS OVERHEAD ALONG WITH DISTURBANCES IN THE ZONAL FLOW ALOFT. HOWEVER...IF THE BOUNDARY IS FARTHER SOUTH...THEN COOL AND LESS HUMID CONDITIONS WILL KEEP UNSETTLED WEATHER TO OUR SOUTH. AS OF NOW...THE FORECAST LEANS TOWARD THE FIRST SCENARIO WHICH IS IN AGREEMENT WITH MOST OF THE GUIDANCE. HOWEVER...THERE IS STILL UNCERTAINTY WITH THE MODEL FORECASTS DURING THIS TIME FRAME. A STRONGER UPPER-LEVEL DISTURBANCE/SURFACE LOW MAY ENHANCE THE THREAT FOR CONVECTION WEDNESDAY NIGHT THROUGH THURSDAY IF THE BOUNDARY IS FARTHER NORTH NEAR THE MASON-DIXON LINE. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... VFR CONDITIONS EXPECTED TODAY THROUGH SUNDAY. SOME PATCHY FOG COULD DEVELOP IN SPOTS OVERNIGHT INTO EARLY SUNDAY BUT CONFIDENCE IN DIRECT IMPACT TO ANY TERMINAL IS LOW AND MENTION WILL BE KEPT OUT OF THE TAFS AT THIS TIME. HIGH PRESSURE WILL ALLOW FOR DRY CONDITIONS SUNDAY NIGHT. A WEAK COLD FRONT MAY TRIGGER AN ISOLATED THUNDERSTORM MONDAY...BUT MOST AREAS WILL BE DRY. AN ISOLATED SHOWER/THUNDERSTORM IS POSSIBLE TUESDAY...BUT AGAIN MOST AREAS WILL END UP DRY. THERE MAY BE A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS DURING THE MIDDLE PORTION OF NEXT WEEK. && .MARINE... WINDS WILL LIKELY REMAIN BELOW SCA THROUGH SUNDAY. A WEAK COLD FRONT WILL CROSS THE WATERS BY EARLY THIS AFTERNOON BUT WIND GUSTS SHOULD REMAIN BELOW SCA CRITERIA. HIGH PRESSURE WILL REMAIN NEAR THE WATERS SUNDAY NIGHT. A WEAK COLD FRONT WILL PASS THROUGH THE WATERS LATE MONDAY INTO MONDAY NIGHT. SOUTHWEST WINDS AHEAD OF THE BOUNDARY MAY GUST AROUND SCA CRITERIA AHEAD OF THE FRONT MONDAY AFTERNOON AND EVENING. WESTERLY WINDS BEHIND THE BOUNDARY MAY GUST NEAR SCA CRITERIA OVERNIGHT MONDAY. A STATIONARY BOUNDARY WILL SETUP NEAR THE WATERS DURING THE MIDDLE PORTION OF NEXT WEEK...AND UNSETTLED CONDITIONS ARE POSSIBLE DURING THIS TIME. && .TIDES/COASTAL FLOODING... FULL MOON WILL CAUSE ASTRONOMICALLY HIGH TIDES TODAY. WHILE TIDES WILL BE SLIGHTLY ABOVE NORMAL...AM NOT EXPECTING ANY FLOODING. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...BJL NEAR TERM...KRW SHORT TERM...BJL/KRW LONG TERM...BJL AVIATION...BJL/KRW MARINE...BJL/KRW TIDES/COASTAL FLOODING...KRW

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