000 FXUS61 KLWX 150025 AAA AFDLWX AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 825 PM EDT MON SEP 14 2009 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH TONIGHT. A BACKDOOR COLD FRONT WILL APPROACH THE AREA LATE TUESDAY BEFORE STALLING TUESDAY NIGHT. THE FRONT WILL LINGER NEAR OR JUST SOUTH OF THE REGION WEDNESDAY AND THURSDAY BRINGING A GOOD CHANCE FOR PRECIPITATION. ANOTHER COLD FRONT WILL PASS THROUGH THE REGION LATE IN THE WEEK INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... MINIMAL CHGS NEEDED TO GRIDS TNGT. MOSTLY CLR SKIES XPCD AS HIPRES BUILDS. DEWPTS FROM MID 50S TO MID 60S ACRS FCST AREA WILL COMBINE WITH PRIME RADIATIONAL COOLING CONDITIONS TO YIELD FOG IN TYPICAL AREAS. PREV DISCUSSION FOLLOWS... HIGH PRESSURE WILL REMAIN OVER THE REGION TONIGHT BRINGING MORE DRY AND SEASONABLE CONDITIONS. MIN TEMPS WILL RANGE FROM THE 40S IN THE COLDER PORTIONS OF THE POTOMAC HIGHLANDS...TO THE 50S ACROSS THE SHENANDOAH VALLEY...TO THE MID 60S IN DOWNTOWN WASHINGTON AND BALTIMORE. WITH MAINLY CLEAR SKIES AND LIGHT WINDS OVERNIGHT...HAVE ADDED PATCHY FOG INTO SOME RURAL LOCATIONS AS WELL AS SHELTERED VALLEYS. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... A COLD FRONT WILL APPROACH THE REGION FROM THE NORTH TUESDAY...BUT IT WILL REMAIN TO OUR NORTH DURING THE DAY. THIS WILL RESULT IN MORE DRY CONDITIONS. MAX TEMPS AHEAD OF THE FRONT WILL BE CLOSE TO MONDAYS...IN THE MID 80S ACROSS MOST LOCATIONS WITH 70S IN THE MOUNTAINS. A THETA E RIDGE AHEAD OF THE FRONT WILL PROVIDE A MORE SUBSTANTIAL CU BUILDUP DURING THE AFTERNOON HOURS. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... THE BACKDOOR CDFNT SAGS ACRS CWFA TUE NGT...AND LKLY WL STALL SOMEWHERE ACRS OR JUST S OF AREA. CNDN HIPRES STRETCHES ACRS THE GRTLKS/NEW ENGLND...AS AN UPR TROF SWINGS ACRS THE NERN CONUS. MONITORING GDNC CYCLES FOR SVRL DAYS NOW...THE LTST RUNS CONTAIN A BIT MORE MSTR...AS ONSHORE FLOW ENSUES RATHER SWIFTLY AND INTENTLY. IT WL BECOME CLDY THRU THE EVNG...AND CANNOT RULE OUT A LTL LGT PCPN OVNGT...SPCLY CLSR TO THE PROLONGED MARITIME FLOW IN NERN MD WHERE PVA ENHANCEMENT PSBL. WED-THU SEEM WETTER W/ EACH SUCCESSIVE RUN AS ISENT LIFT...AND PERHAPS A FEW EMBEDDED S/WVS...TRACKS ALNG STALLED BNDRY AND OVERRUNS E/NELY ONSHORE FLOW. POPS WED AFTN-THU NOW UP TO LKLY...W/ DECENT QPF GIVEN GLFMEX AND ATLC MSTR SHUD BOTH BE IN PLAY. TEMPS WL BE CONTINGENT ON EXACTLY WHERE CDFNT STALLS OUT...WHICH MAKES IT QUITE A CHALLENGE. ADJUSTMENTS OFFER A GREATER MAXT GRADIENT FM PTMC HIGHLANDS TO CNTRL VA/SRN MD. MIN-T SHUD BE FAIRLY CLOSE TO DEWPTS...WHICH SHUD BE CLOSE TO IF NOT ABV 60F CONSIDERING ANTICIPATED PCPN INVOF STALLED FNT. DONT THINK HIPRES WL EDGE INTO AREA. THE XTNDD FCST REMAINS CONTINGENT UPON THE STALLED SFC BNDRY AND EAST COAST TROF...WITH PERTURBATIONS DIVING INTO TROF AXIS FM BOTH STREAMS. WHILE RESOLVING S/WVS BECOME MORE PROBLEMATIC AT THIS PT...GNLY IT APPEARS TO BE AN UNSTTLD PTTN. TO THAT END...HV INCRSD POPS ONCE AGN THRU SAT. FRI WL BE ON THE WARMER SIDE...AND WL DROP TEMPS SAT IN RESPONSE TO S/WV AND ITS SFC REFLECTION. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... VFR CONDITIONS XPCD THRU TUE AFTN. PATCHY BR PSBL LATE TNGT...SPCLY VCTY KCHO AND KMRB...BUT VSBYS AOA 6 SM XPCD. LGT WINDS BCM WNWLY DURG TUE MRNG AS SCT CU FIELD DVLPS MID-LATE MRNG. CIGS INCR TUE AFTN INTO TUE NGT AS BACKDOOR CDFNT STALLS ACRS AREA. ENELY LLVL FLOW AND OVERRIDING MSTR FM THE GLFMEX CST WL LEAD TO POOR FLYING CONDS WED-THU. MVFR SHUD BE PERVASIVE...AND PDS OF IFR PSBL. FLGT RESTRICTIONS LKLY TO LINGER INTO FRI. && .MARINE... HIGH PRESSURE WILL REMAIN OVER THE WATERS TONIGHT. A COLD FRONT WILL APPROACH THE WATERS TUESDAY. NO FLAGS ARE EXPECTED THROUGH TUESDAY. BACKDOOR CDFNT XPCTD TUE NGT...W/ FNT LKLY TO STALL SOMEWHERE ACRS WATERS. THE ELY COMPONENT TO THE FLOW INTENSIFIES WED-THU AS HIPRES BLDS ACRS NEW ENGLND. MEANWHILE...A DISTURBANCE ALNG THE GLF CST WL OVERRIDE LLVL MARITIME FLOW...MAKING FOR WET CONDS ON TOP OF THE STRONG WNDS. SCA PSBL LT WED-ELY THU. UNSTTLD WX SHUD CONT THRU END OF WK. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ UPDATE...KRAMAR PREV DISCUSSION...LASORSA/HTS