000 FXUS61 KLWX 300650 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 250 AM EDT SAT AUG 30 2008 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION LATE TODAY AND THIS EVENING. HIGH PRESSURE WILL BUILD IN BEHIND THIS FRONT AND HOLD THROUGH MUCH OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AREAS OF FOG TO DEAL WITH THIS MORNING. AIRMASS IS MOIST AND WINDS ARE LGT. WILL MENTION FOR THE EARLY PTN OF THE PERIOD. THREE STNS IN THE S AND W BLO 1SM AS OF 06Z. DO NOT SEE A WIDESPREAD DENSE EVENT...SO WILL FORGO ANY ADVISORIES. FOG SHD BRN OFF WITH DAYTIME HTG. FOR THE AFTN...ATMOSPHERE IS LIGHTLY UNSTABLE. PW VALUES ARND 1.5". NO SHR TO SPEAK OF AND FRZG LVLS/WET BULB ZEROES NOT CONDUCIVE FOR HAIL TO BE PRODUCED. EVIDENCE OF A SFC BOUNDARY SERN ZONES THIS AFTN AND SOME UPR LVL ENERGY ROLLS ACRS THE AREA AS H5 HGTS BUILD. EXPECTING ISOLD CONVECTIVE ACTIVITY NWRN ZONES AND SCT SE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/... CONT DRYING AND STABILIZATION WILL ALLOW ANY CONVECTION TO DISSIPATE THIS EVENING. WILL CONT LOW CHC POPS EARLY...THEN LOWER THEM OVERNIGHT. A RDG OF HIPRES IS FCST FROM SERN ONTARIO TO PA BY 12Z SUN. && .LONG TERM /SUNDAY THROUGH FRIDAY/... 500MB HEIGHT/ANOMALY PATTERN DURING THE PAST 5 DAYS SHOWS A TROUGH DEVELOPING ACROSS WESTERN CANADA AS RIDGING TAKES PLACE OVER EASTERN CANADA. WATER VAPOR LOOP SHOWS A SHORT WAVE PASSING OVER THE UPPER GREAT LAKES. RIDGING HAS A HOLD OVER THE SOUTHWEST CONUS AND OFF THE SOUTHEAST COAST...WITH A WEAKNESS IN THE HEIGHT FIELD OVER THE SOUTHEAST STATES. SURFACE MAP LAST EVENING PLACED A WARM/STATIONARY BOUNDARY FROM NEAR PITTSBURGH SOUTHEAST THROUGH WEST VIRGINIA AND EAST ACROSS SOUTHERN VIRGINIA. THE NEXT COLD FRONT WAS APPROACHING THE OHIO VALLEY. FORECAST IS BASED ON 11 PM NATIONAL HURRICANE CENTER FORECAST TRACK FOR GUSTAV (ADVISORY 21) AND HANNA (ADVISORY 8). COLD FRONT SHOULD BE PRESSING THROUGH REGION SUNDAY MORNING...WITH HIGH PRESSURE BUILDING IN THROUGH MIDWEEK. THERE COULD BE ENOUGH RESIDUAL MOISTURE IN SOUTHWEST VALLEYS FOR A FEW DIURNAL SHOWERS SUNDAY...BUT FELT TREND COULD BE EVALUATED BY NEXT SHIFT BEFORE INTRODUCING LOW-END POPS. DID INCREASE CLOUD COVER AND INDICATE CLEARING TREND FROM THE NORTHEAST AS DRIER AIR FILTERS INTO THE REGION. SUBSIDENCE FROM BUILDING HEIGHTS ALOFT SHOULD ALLOW FOR A WARMING TREND THROUGH THE WEEK. WILL HAVE TO KEEP MONITORING THE TROPICS FOR ANY POSSIBLE IMPACT BEYOND CURRENT FORECAST CYCLE. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... IFR/MVFR CEILINGS AND VISBYS WILL RAPIDLY IMPROVE WITH DAYTIME HEATING. ISOLD TO SCT CONVECTION THIS AFTERNOON AND EVENING ALONG AND AHEAD OF THE COLD FRONT. HIGH PRESSURE BUILDS IN SUNDAY INTO THE EARLY WORK WEEK BEHIND THE NEXT COLD FRONT. && .MARINE... GRADIENT DOES NOT INDICATE THE NEED FOR FLAGS TODAY AND TONIGHT. HIGH PRESSURE BUILDS IN SUNDAY INTO THE EARLY WORK WEEK BEHIND THE NEXT COLD FRONT. && .HYDROLOGY... MUCH NEEDED RAIN FROM FAY REMNANT MOISTURE IS DONE. BIG MEADOWS IFLOWS GAGE/SKYLINE DRIVE/PAGE COUNTY VA WON THE PRIZE FOR A STORM TOTAL. 7.19". GIVEN DRY ANTECEDENT CONDITIONS AND TIME OF YEAR...THE HEFTY TOTALS IN THE MTNS CAUSED NO FLOOD PROBS. NO ISSUES EXPECTED SOON. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...ROGOWSKI NEAR TERM...RDH SHORT TERM...RDH LONG TERM...ROGOWSKI AVIATION...RDH/ROGOWSKI MARINE...RDH/ROGOWSKI HYDROLOGY...RDH