Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 290129 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 929 PM EDT THU MAY 28 2015 .SYNOPSIS...
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HIGH PRESSURE OVER LAKE ONTARIO WILL SHIFT SOUTHEAST AND REINFORCE HIGH PRESSURE OFFSHORE THROUGH FRIDAY. SOUTHERLY WINDS WILL CONTINUE TO BRING WARM AND HUMID CONDITIONS TO THE MID- ATLANTIC THROUGH SATURDAY. A COLD FRONT WILL ARRIVE SUNDAY AND STALL OVER THE AREA THROUGH MONDAY.
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&& .NEAR TERM /THROUGH FRIDAY/...
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AS OF 01Z...1025MB SFC HIGH ACROSS LAKE ONTARIO WITH WEAK CONVERGENCE APPARENT IN IR IMAGERY ALONG THE EASTERN SEABOARD. RADAR IS QUIETING DOWN THOUGH REMNANT BOUNDARIES COULD CONTINUE TO BRING ISOLATED SHOWERS AND THUNDERSTORMS. ANOTHER WARM OVRNGT ON TAP FOR THE AREA W/ LOWS IN THE 60S...L70S IN THE CITIES.
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&& .SHORT TERM /FRIDAY NIGHT THROUGH 6 PM FRIDAY/...
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HIGH PRESSURE SHIFTS SOUTHEAST OFF THE MID-ATLANTIC COAST FRIDAY MORNING. THIS REINFORCING HIGH WILL FURTHER AID SLY FLOW. COULD SEE MORE MORNING PRECIP ACTIVITY WEST OF THE BLUE RIDGE. MAX TEMPS 85-90F.
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&& .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... THE OVERALL SYNOPTIC PATTERN CHANGES VERY LITTLE THROUGH FRIDAY NIGHT AND SATURDAY. THE REGION WILL REMAIN UNDER THE INFLUENCE OF A RIDGE OF HIGH PRESSURE WHICH WILL BE CENTERED OFFSHORE DURING THIS TIME PERIOD. THE NEAREST SHORTWAVE TROUGH WILL BE PASSING THROUGH ONTARIO AND QUEBEC...BUT IT WILL NOT INFLUENCE THE HEIGHT FIELD OVER THE MID-ATLANTIC UNTIL SUNDAY. THE ASSOCIATED COLD FRONT PUSHING INTO THE GREAT LAKES WILL TIGHTEN THE PRESSURE GRADIENT...WHICH MAY TICK UP THE BREEZE A LITTLE SATURDAY. IN TERMS OF PRECIP CHANCES...ANY CONVECTION FROM FRIDAY AFTERNOON SHOULD WANE DIURNALLY. THE RIDGE WILL STILL BE STRONG SATURDAY. SLIGHTLY DRIER AIR (PER PWAT VALUES) MAY ADVECT INTO THE SE THIRD OF THE CWA...AND A CAP MAY BE IN PLACE AS WELL. HAVE THUS TRIMMED POPS BACK A BIT...AND LOCATIONS EAST OF THE BLUE RIDGE MAY VERY WELL BE DRY AS CONVECTION WILL LARGELY BE TERRAIN DRIVEN. ANY UNCERTAINTY WOULD HINGE IN A DISTURBANCE RIDING THE EDGE OF THE RIDGE IN WSW FLOW ALOFT...AND PWAT AND CAPE DO REMAIN HIGHER OVER THE POTOMAC HIGHLANDS. HIGHS SATURDAY WILL RISE A FEW DEGREES...ESPECIALLY IN LOCATIONS WHICH SEE MORE SUN. MID 80S TO NEAR 90 EXPECTED. LOWS BOTH FRIDAY NIGHT AND SATURDAY NIGHT ONLY FALL INTO THE 60S TO AROUND 70. A COLD FRONT WILL SLOWLY PUSH SOUTHEASTWARD ACROSS THE REGION SUNDAY INTO SUNDAY NIGHT. SHOWERS AND THUNDERSTORMS WILL FORM AHEAD OF AND ALONG THE FRONT. TEMPERATURES WILL BE ABOUT 3 TO 5 DEGREES ABOVE NORMAL. OF COURSE...THE MORE CLOUD COVER AND CONVECTION THAT WE SEE ASSOCIATED WITH THE FRONT COULD KNOCK THOSE HIGHS DOWN A LITTLE. HIGH PRESSURE OVER THE NORTHEAST AND THE EASTERN CANADIAN MARITIMES WILL WEDGE ITSELF SOUTHWARD ALONG THE EAST COAST MONDAY THROUGH WEDNESDAY. THIS HIGH WILL USHER IN COOLER AIR. A PASSING MID LEVEL DISTURBANCE ACROSS THE LOWER GREAT LAKES AND SMALLER SHORTWAVES MOVING ACROSS THE EASTERN OHIO VALLEY WILL BRING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ALONG AND JUST ON THE COOL SIDE OF A COLD FRONT MONDAY. ALTHOUGH THERE STILL LINGERS A CHANCE OF RAIN SHOWERS MONDAY NIGHT THROUGH TUESDAY NIGHT...DRIER AIR WILL PREVAIL INTO WEDNESDAY. TEMPERATURES MAY ONLY TOP OUT IN THE UPPER 60S TO LOWER 70S MONDAY THROUGH WEDNESDAY WITH LOWS IN THE MIDDLE 50S. HIGH PRESSURE WILL MOVE TO THE COAST THURSDAY THAT WILL ALLOW A MILDER RETURN FLOW OF AIR AND HELP TO BRING HIGH TEMPERATURES BACK UP INTO THE LOWER 80S THURSDAY. && .AVIATION /01Z FRIDAY THROUGH TUESDAY/...
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PATCHY FOG PSBL AFTR MDNGT FOR VALLEYS AND PIEDMONT INCLUDING MRB/CHO/IAD. SUB-VFR VSBY POSSIBLE SATURDAY MORNING IN BR...WITH THE HIGHEST CHANCES AT MRB AND CHO. AS OF NOW...MRB HAS THE BEST CHANCE OF BEING AFFECTED BY A STRAY THUNDERSTORM ON SATURDAY AFTERNOON/EVENING. MVFR OR IFR CONDITIONS POSSIBLE SUNDAY THROUGH MONDAY WITH SHOWERS AND THUNDERSTORMS IN PARTS OF THE AREA.
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&& .MARINE...
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SOUTH FLOW CHANNELS THIS EVENING TO AROUND 15 KT. STILL THE POTENTIAL FOR A GUSTY SHOWER OR THUNDERSTORM REST OF THE EVENING INSPITE OF A MOSTLY QUIET AFTERNOON/EARLY EVENING. SLY FLOW 10 TO 15 KT FRIDAY AS HIGH PRESSURE IS REINFORCED OFF THE MID-ATLANTIC COAST. SOUTHERLY FLOW INCREASES SATURDAY INTO SATURDAY NIGHT BETWEEN HIGH PRESSURE OFFSHORE AND A COLD FRONT OVER THE GREAT LAKES. SCA CONDITIONS COULD BE ACHIEVED...ESPECIALLY OVER THE BAY. ANY THUNDERSTORM ACTIVITY FROM FRIDAY NIGHT THROUGH SATURDAY NIGHT WILL BE ISOLATED. COLD FRONT STALLS ACROSS THE CENTRAL MID-ATLANTIC SUNDAY AND MONDAY. GUSTY SHOWERS AND THUNDERSTORMS...ALONG WITH SMWS POSSIBLE SUNDAY INTO TUESDAY.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ UPDATE...JACKSON PREVIOUS...WOODY!/ADS/KLW

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