AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 1104 AM EDT MON APR 18 2011 .SYNOPSIS... HIGH PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST THROUGH WEDNESDAY. LOW PRESSURE SLOWLY TRACKS NORTHEAST FROM THE SOUTHERN PLAINS TUESDAY. THE LOW WILL MOVE INTO EASTERN CANADA WEDNESDAY NIGHT...AND WILL PUSH A COLD FRONT THROUGH THE MID ATLANTIC STATES BY THURSDAY MORNING. HIGH PRESSURE WILL RETURN FOR THURSDAY AFTERNOON INTO FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... STATUS ON POST-STORM SURVEYS... PRELIMINARY REPORTS FROM SATURDAYS TORNADOES HAVE BEEN COMPLETED FOR BERTIE COUNTY, NC AND DINWIDDIE COUNTY, VA...WITH A MORE COMPLETE REPORT FOR GLOUCESTER COUNTY, VA TO BE COMPLETED THIS AFTERNOON...AND LUNENBURG COUNTY, VA TUESDAY. PLEASE SEE THE LATEST PUBLIC INFORMATION STATEMENT (WBCPNSAKQ)...LOCAL STORM REPORTS (WBCLSRAKQ)... AS WELL AS AVAILABLE ON OUR WEB PAGE (WWW.WEATHER.GOV/WAKEFIELD) FOR MORE INFORMATION. NEAR TERM FORECAST DISCUSSION... CRNT FCST ON TRACK WITH ONLY MINOR CHANGES MADE TO GRIDS/ZFP LATE THIS AM. PLNTY OF HIGH LVL MSTR ARND TO CALL SKIES PT SUNNY. WRM WITH HIGHS U70S TO NR 80 W OF BAY...COOLER AT THE COAST WITH HIGHS IN THE 70S DUE TO AN ONSHORE SRLY WND FLOW. WNDS INCRS AND BECOME GUSTY THIS AFTRN UPWARDS TO 30 MPH. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... A QUASI-STATIONARY/WARM FRNTL BNDRY WILL CONTINUE TO MEANDER ALNG OR JUST S OF THE MASON DIXON LINE TONIGHT AND TUE. GFS/NAM SHOW SOME LGT QPF AMTS INTO NRN 1/2 OF THE CWA ON TUE AFTN AND TUE NGT. A LOOK AT BUFR SNDGS SHOWS VERY LMTD/SHALLOW MSTR SO WILL CARRY A 20% AT MOST...AND CONFINE THIS TO FAR NRN ZONES TUE AFTN/EVENG. LOWS TONIGHT MAINLY IN THE 50S AND HIGHS TUE RANGING FROM THE LWR 80S OVER MUCH OF THE INTERIOR OF VA/NE NC...UPR 70S FAR NORTH AND AGAIN LOCALLY IN THE 60S ALONG THE COAST OF THE ERN SHORE. SKIES AVG OUT PTLY SUNNY. WED...A MORE SIGNIFICANT SHORTWAVE DIVES SE FROM THE NRN PLAINS AND INTO THE GRT LAKES. GFS/NAM/ECMWF IN GOOD AGREEMENT W/ OVERALL EVOLUTION OF THE PATTERN...KEEPING THE BULK OF UPR SUPPORT WELL OFF TO OUR N. MAIN TRIGGER FOR PRECIP WILL BE THE COLD FRONT ITSELF...PRIMARILY WED EVENG/ERLY THU AM. MODELS DO SHOW SOME INCSRG SHALLOW LOW LVL MSTR ERLY WED AM SO HAVE BUMPED UP CLOUD CVR TO PTLY-MCDY AROUND SUNRISE WED. OTHERWISE..STRONG LOW LVL SW FLOW LOOKS TO BRING A VERY WARM AND BREEZY DAY TO ALL AREAS WED...HIGHS INTO MID-UPR 80S MOST AREAS W OF THE BAY...LWR 80S INTERIOR ERN SHORE AND 70S IMMEDIATE COAST OF THE ERN SHORE. INSTABILITY INCREASES WED AFTN...SFC BASED CAPES PROGGED AT 2000 J/KG BUT THIS IS PROBABLY A BIT OVERDONE DUE TO SFC DEW PTS IN THE 60S (MIXING WILL LIKELY DROP THEM INTO THE MID- UPR 50S IN THE AFTN). EXPECT SKIES TO AVG OUT PTLY- TO MSTLY SUNNY WED FROM LATE MRNG THRU MID AFTN...W/ INCSRG CLOUDS LATE...AND A CHC FOR SHWRS/TSTMS BY LATE AFTN IN THE WEST...AND BY ERLY EVENG FARTHER E (STRG SSW FLOW LOOKS TO INHIBIT STORM DEVELOPMENT WELL AHEAD OF THE FRONT). CAPPED POPS AT 30-40% AS UPR SUPPORT WEAKENS DUE TO MAIN SHORTWAVE TRACKING THROUGH THE GRT LAKES. ORIENTATION OF THE FRONT IS GNLY NOT FAVORABLE FOR SVR WX...SHEAR LOOKS FAIRLY WEAK AND IS UNIDIRECTIONAL (SW). SPC HAS ONLY "SEE TEXT" AT THIS PT. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... SOMEWHAT OF AN UNSETTLED PATTERN WED NIGHT THROUGH NEXT WEEKEND... AS THE COLD FRONT PUSHES THROUGH THE FCST REGION BY THU...STALLS OVER THE SE REGION LATE THU INTO FRI...THEN LIFTS BACK N AS A WARM FRONT FRI NIGHT AND SAT. WILL CONTINUE WITH THE LOW POPS WED NIGHT INTO THU WITH THE COLD FRO PA...AS BELIEVE THE WEAKENING INSTBY ALONG WITH THE THE QUASI-ZONAL FLOW ALOFT AND THE SFC FRONT BECOMING MORE W-E ORIENTED WITH TIME...WILL LIMIT THE LLVL THETA-E POOLING/MSTR CONVERGENCE POTENTIAL AND THUS THREAT FOR MORE WIDESPREAD SHOWERS/TSTMS. HIGHS THU COOLER BEHIND THE FRONT...60S NEAR THE COASTS TO LOWER 70S FARTHER INLAND. FCST CONFIDENCE DIMINISHES SOMEWHAT BY FRI-SAT...GIVEN THE DIVERGING GFS/ECMWF SOLUTIONS. BOTH M0DELS INDICATE A CAD/RIDGE WEDGE SETTING UP ON FRI ACROSS THE FCST AREA (N OF THE STATIONARY FRONT)...HOWEVER THESE MODELS SHOW BIG DIFFERENCES IN TERMS OF THE DEGREE OF OVERRUNNING MOISTENING INTO THE MID ATLC REGION. THE ECMWF REMAINS THE WETTER MODEL...WHILE THE GFS REMAINS SHARPER WITH THE LLVL A-CYCLONIC FLOW AND (THUS) DRIER AIR HOLDING ON ACROSS THE MID ATLC REGION. GIVEN THE DEPICTED PATTERN...WITH THE DEEPENING EASTERLY FLOW...HAVE CONTINUED TO SIDE WITH THE ECMWF (AS HAS HPC PER THEIR GUIDANCE)...THEREBY MAINTAINING A CHANCE OF RAIN FRI INTO SAT. SUN EVEN MORE NEBULOUS IN TERMS OF RAIN CHANCES... HOWEVER AGAIN OPTED FOR POPS AOA CLIMO (AT LEAST 30%) GIVEN (AGAIN) THE CLOSE PROXIMITY TO THE STALLED LLVL FRONTAL BNDRY. HIGHS OVER THE WEEKEND AROUND 70 NEAR THE COASTS AND INTO THE MID-UPR 70S FARTHER INLAND. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... VFR CONDS AND MAINLY A SW FLOW WILL PREVAIL TODAY. VFR CONDS WILL CONTINUE TUE-WED WITH BREEZY SW WINDS IN THE AFTERNOONS. CHANCE FOR LWR CIGS/VSBYS WITH SHWRS/TSTMS LATE WED/ERLY THURS. && .MARINE... SCA CONDITIONS CONTINUE OVER THE NRN CSTL WATERS EARLY THIS MORNING...MAINLY DUE TO THE LINGERING SWELLS OF 5-6 FT. FLAGS SHOULD BE ABLE TO COME DOWN AT 6AM AT SEAS CONTINUE TO SUBSIDE...BUT WILL CONTINUE TO MONITOR LATEST MARINE OBS AND WILL EXTEND LONGER IF NECESSARY. BY LATE THIS AFTERNOON...LONG FETCH SOUTHERLY FLOW INCREASES TO 15-20 KTS FOR A TIME. THIS MAY CAUSE SEAS TO BUILD BACK OVER 5 FT FOR THE NRN CSTL WATERS TONIGHT. WILL LATE DAYSHIFT MAKE THE CALL ON WHETHER OR NOT AN SCA WILL BE NECESSARY FOR TONIGHT. DID GO AHEAD AND HOIST AN SCA FOR THE CHESAPEAKE BAY STARTING AT 4PM THIS AFTERNOON AND RUNNING THROUGH EARLY TUES MORNING. MINIMAL SMALL CRAFT CONDITIONS (WINDS 15-20 KTS) ARE EXPECTED DURING THIS TIME. && .HYDROLOGY... FLOOD WRNG CONTS ON JAMES RIVER AT RICHMOND WESTHAM AND THE CITY LOCKS. CARTERSVILLE WAS CANCELLED AS IT CRESTED JUST BELOW FLOOD STAGE THIS AM. SEE WBCFLSAKQ AND WBCFLWAKQ FOR MORE INFORMATION. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EDT TUESDAY FOR ANZ630>632-634. && $$ SYNOPSIS...LKB/MPR