Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 220126 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 926 PM EDT THU AUG 21 2014 .SYNOPSIS... DEEP HIGH PRESSURE WILL REMAIN CENTERED OVER THE DEEP SOUTH THROUGH THIS WEEKEND. SURFACE HIGH PRESSURE WILL DEVELOP OVER NEW ENGLAND ON FRIDAY AND DRIFT SOUTHWEST...WITH AN ONSHORE FLOW OVER THE AREA LATE FRIDAY THROUGH MONDAY. HIGH PRESSURE WILL THEN PERSIST OVER THE MID-ATLANTIC THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... DIURNAL DOWNWARD TREND IN THUNDERSTORMS THIS EVENING. 1000 J/KG SBCAPE PERSIST EAST OF I-95 WHERE ISO/SCT TSTMS WILL PERSIST UNTIL AROUND MIDNIGHT. LIGHT WLY/NWLY FLOW AND HIGH/MID LEVEL CLOUDS SHOULD LIMIT FOG MORE THAN LAST NIGHT. LOWS IN THE 60S W OF I-95...L70S E. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... BNDRY RMNG IN THE AREA FRIDAY WL MOST LKLY SERVE AS A FOCUS FOR TSTMS. WL KEEP POPS IN CHC RANGE. AGN SVR THREAT LOOKS LOW - LO LVL WIND FIELD IS WEAK...CAPE IS NOT OVERLY IMPRESSIVE. FFG IS RLTVLY HIGH. HIGHS IN THE MU80S. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... AN UPPER LEVEL VORTICITY MAX WILL DIP THROUGH THE AREA OVERNIGHT FRIDAY...BRINGING ANOTHER BOUT OF ENHANCED RAINFALL. SURFACE HIGH PRESSURE CENTERED OVER NEW ENGLAND WILL RIDGE DOWN THE EAST COAST AS AN UPPER LEVEL SUBTROPICAL RIDGE BUILDS OVER THE EASTERN US. THE SURFACE RIDGE BUILDING DOWN INTO THE AREA WILL WORK WITH LOW PRESSURE OFF OF THE CAROLINA COAST TO BRING ONSHORE FLOW INTO THE MID-ATLANTIC BEGINNING SATURDAY MORNING. THE PRIMARY EFFECTS OF THE INCOMING MARINE AIRMASS WILL BE SEASONABLY COOL TEMPERATURES AND MOSTLY CLOUDY TO OVERCAST SKIES. EXPECT HIGHS ON SATURDAY...SUNDAY AND MONDAY TO ONLY BE IN THE MID TO UPPER 70S. HIGH PRESSURE WILL MOVE MORE OVERHEAD BY MONDAY NIGHT AND ONSHORE FLOW WILL MOSTLY BE SHUT OFF. LIGHT SOUTHERLY FLOW WILL BEGIN TO FILL INTO THE AREA TUESDAY...LEADING TO AN TREND TOWARD MORE SEASONABLE TEMPERATURES BY THE MIDDLE OF THE WEEK WITH HIGHS NEAR 80 ON TUESDAY AND IN THE MID 80S WEDNESDAY AND THURSDAY. HOWEVER...WITH A RATHER DRY PROFILE CONVECTION IS UNLIKELY TUESDAY OR WEDNESDAY. THE NEXT THREAT FOR STORMS ACROSS THE AREA SHOULD BE THURSDAY AS A COLD FRONT APPROACHES THE AREA. && .AVIATION /01Z FRIDAY THROUGH TUESDAY/... LIGHT WLY FLOW AND CLOUDS SHOULD KEEP FOG AT BAY TONIGHT IN THE WAKE OF THUNDERSTORMS. STILL...SOME MVFR VSBYS SHOULD BE EXPECTED. ANOTHER ROUND OF THUNDERSTORMS FROM THE NORTHWEST FRIDAY AS HIGH PRESSURE PERSISTS OVER THE E-CNTRL CONUS. PERIODS OF LOW CEILINGS ARE POSSIBLE AS AN UPPER LEVEL VORT MAX CROSSES THE AREA FRIDAY NIGHT AND THEN AGAIN OVER THE WEEKEND AND INTO EARLY NEXT WEEK AS A MARINE AIRMASS SETTLES INTO THE AREA. && .MARINE... LIGHT SLY FLOW BECOMES WLY FRIDAY AS A WEAK COLD FRONT MOVES THROUGH. THEN A BACK DOOR FRONT COMES THROUGH FRIDAY AFTERNOON WITH A SWITCH TO ELY FLOW THAT PERSISTS THROUGH THE WEEKEND. A SMALL CRAFT ADVISORY MAY BE NECESSARY FOR THE WIDEST ZONES OF THE LOWER MARYLAND CHESAPEAKE BAY AND THE LOWER TIDAL POTOMAC SATURDAY AFTERNOON THROUGH SUNDAY NIGHT IN BREEZY EASTERLY FLOW. && .TIDES/COASTAL FLOODING... WATER LEVELS HAVE DROPPED BELOW HALF A FOOT AS LOW PRESSURE HAS PUSHED FARTHER AWAY FROM THE MOUTH OF THE CHESAPEAKE. THERE IS NO COASTAL FLOODING THREAT WITH HIGH TIDE TONIGHT. A WLY FLOW EARLY FRIDAY WILL CONTINUE TO LOWER WATER...BUT AN ELY FLOW IS EXPECTED FRIDAY EVENING THROUGH THE WEEKEND...RAISING SOME COASTAL CONCERNS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ UPDATE...JACKSON PREVIOUS...WOODY!/CEB

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