FXUS61 KRNK 291802 AAA AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 200 PM EDT SUN AUG 29 2004 .AVIATION... OUTER RAIN BAND OF GASTON HAS MADE MORE WRN PROGRESS THIS AFTERNOON THAN NRN PROGRESS. LIGHT SHOWERS OR SPRINKLES MAY BRUSH DAN...BUT IT DOES NOT LOOK LIKE ANY SUBSTANTIAL SHOWERS WILL BE IN THE AREA TILL AFTER 22Z. CURRENT FCST TRACK OF THE REMNANTS OF GASTON BRING IT JUST WEST OF RALEIGH AROUND 8 AM MONDAY. DAN HAS THE BEST CHC FOR HEAVY RAIN...AND IT LOOKS LIKE IT WILL BE TOWARD MORNING. MODELS ARE SHOWING SOME UPSLOPE ENHANCEMENT ALONG THE BLUE RIDGE OVERNIGHT...SO I HAVE STARTED PERIODS OF SHOWERS IN ROA TAF AFTER 00Z. HAVE KEPT THE RAIN OUT OF LYH UNTIL NEAR MIDNIGHT. CONVECTION THIS AFTERNOON OUTSIDE OF THE SUBSIDENCE AREA FROM GASTON HAS BEEN WEST OF BLF AND LWB...SO I REMOVED THE VICINITY THUNDERSTORMS FOR LATE AFT/EVE. HAVE JUST INCLUDED PERIODS OF SHOWERS TOWARD MORNING FOR BLF/LWB AS THEY WILL BE ON THE WRN EDGE OF THE RAIN BANDS. CIGS OVERNIGHT SHOULD BECOME MVFR/IFR ALL LOCATIONS...WITH SOME PERIODS OF LIFR POSSIBLE TOWARD MORNING MAINLY ROA/LYH/DAN. RAIN SHOULD BE PULLING OUT AROUND 18Z SUNDAY. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 1045 AM EDT SUN AUG 29 2004 SHORT TERM (REST OF TODAY)... THICK CIRRUS SHIELD FROM GASTON MOVG INTO SERN SECTIONS OF THE CWA AT THIS TIME...AND SHOULD SPREAD OVER A GOOD PART OF THE AREA THIS AFTERNOON. WILL HAVE TO LOWER MAX TEMPS SOME- ESPECIALLY SERN ZONES SUCH AS NW PIED OF NC. 12Z SOUNDINGS SHOW QUITE A BIT OF DRY AIR ALOFT AND WARM TOO. BECAUSE OF OUTFLOW SUBSIDENCE FROM GASTON...I THINK THERE WILL BE A SHARP CUTOFF TO WHERE AFTERNOON CONVECTION DEVELOPS...AND THAT IT WILL BE EXTREME WRN PARTS OF THE CWA IF AT ALL. OTHERWISE...GASTON RAIN BANDS WILL PROB HOLD OFF TILL THIS EVENING FOR SRN SECTIOSN OF THE CWA. MAIN CHANGE TO FORECAST WILL BE TO TRIM POPS WAY BACK FOR ALL BUT EXTREM WESTERN ZONES...AND THEN INCRESE POPS THIS EVENING IN THE SOUTH SINCE GASTON IS MOVG A LITTLE FASTER. THE FOLLOWING WAS ORIGINALLY ISSUED AT 908 AM EDT SUN AUG 29 2004 SHORT TERM (REST OF TODAY)... WILL ISSUE A QUICK UPDATE SINCE THE DENSE FOG ADVISORY HAS ENDED. STILL WANT TO LOOK AT MORE 12Z DATA BEFORE MAKING ANY CHANGES TO THE REST OF THE FORECAST TODAY. PRELIMINARY LOOKS LEAD ME TO THINK THAT SUBSIDENCE FROM GASTON MAY KNOCK BACK CHANCES OF THUNDERSTORMS ACROSS MUCH OF THE AREA. THE FOLLOWING WAS ORIGINALLY ISSUED AT 739 AM EDT SUN AUG 29 2004 AVIATION... WIDESPREAD LIFR IN THE MTNS THIS MORNING LIFTING MID TO LATE MORNING. SFC TROUGH LINGERING ALONG THE BLUE RIDGE TO GIVE ANOTHER OPPORTUNITY FOR AFTN CONVECTION. COMPLICATED SCENARIO WITH APPROACHING FRONT FROM THE WEST AND TS GASTON TO THE SE. SUBSIDENCE AND MOISTURE ROBBING FROM TS COULD RENDER MUCH OF WESTERN PORTION OF THE AREA DRY WHILE EXTREME WESTERN CWA MAY SEE SOME CONVECTION BEING NEAR THE FRONT. IN THE EAST...TS GASTON IS LKG MORE LIKELY TO SPREAD RAIN/HEAVY RAIN TO DAN AND LYH TONIGHT. THE FOLLOWING WAS ORIGINALLY ISSUED AT 553 AM EDT SUN AUG 29 2004 SHORT TERM (REST OF TODAY)... UPDATING FCST EARLY THIS MORNING FOR A DENSE FOG ADV. VSBYS ONCE AGAIN DROPPING TO NEAR ZERO MANY AREAS ALONG AND WEST OF BLU RDG. ALSO UPDATING TO INCREASE POPS IN SOUTHEAST COUNTIES FOR THE EVENTUAL REMNANTS OF GASTON WHICH IS SPREADING RAIN FAR OUT AHEAD OF IT. ALSO WITH NEW 06Z UPR AIR DATA...06Z MODEL RUNS OF THE ETA AND GFS ARE BOTH SHOWING A QUICKER AND MORE WESTERLY PUSH OF RAIN WELL INTO OUR FA LATE TONIGHT. QPFS LIKELY TO BE HIGHER IN THE PIEDMONT TONIGHT AND MONDAY...HOWEVER SPEED OF SYSTEM SHUD PRECLUDE THE THREAT OF FLOODING. THE FOLLOWING WAS ORIGINALLY ISSUED AT 330 AM EDT SUN AUG 29 2004 SHORT TERM (TODAY THROUGH MONDAY NIGHT)... ENERGY TRACKING QUICKLY THRU THE GREAT LAKES THIS MORNING WILL BRING THE MIDWESTERN COLD FRONT CLOSER TO THE AREA TODAY WHILE TS GASTON WORKS IT WAY ASHORE ALONG THE SC COAST. STUBBORN UPR RIDGE OFF THE COAST REFUSES TO PROGRESS TO THE EAST...DELAYING THE APPROACH OF THE MIDWEST FRONT AND ALLOWING GASTON TO TAKE A MORE WESTERLY TRACK. HOWEVER IT LKS LIKE THE FRONT WILL APPROACH WESTERN COUNTIES ON MONDAY...THEN GET ABSORBED INTO THE REMNANTS OF TS GASTON AS IT PULLS UP THRU EASTERN VA AND ON UP THE EAST COAST. AREAS WITH THE BEST CHC OF RAIN NEXT 48 HOURS ARE THE FAR WESTERN COUNTIES WITH THE FRONT...ALONG WITH EXTREME SE COUNTIES WITH GASTON. IN THE MIDDLE...SUBSIDENCE BETWEEN THE 2 SYSTEMS MAY LEAVE AREAS WITH LITTLE OR NO RAIN. NOT HIGHLY CONFIDENT THAT ANYONE WILL SEE A LOT OF RAIN DURING THIS PD...THUS POPS ARE NO HIGHER THAN 50 PERCENT. HIGH PRESSURE BUILDS IN BEHIND SYSTEMS ON TUESDAY ALTHOUGH TRULY DRY/COOL AIR NEVER QUITE MAKES IT THIS FAR SOUTH. NEW 00Z GFS IS ACTUALLY KEEPING DEEP MOISTURE/PCPN ALONG EXTREME SOUTHERN BORDER THRU MIDWEEK...BUT NOT GOING FOR IT YET. CANADIAN BUILDS THE SFC RIDGE A LITTLE FURTHER SOUTH AND KEEPS IT DRY. BUMPED UP CLOUDINESS ACROSS THE SOUTH FOR THAT PD. LONG TERM (TUESDAY THROUGH SATURDAY)... HIGH PRESSURE BUILDS IN BEHIND SYSTEMS ON TUESDAY ALTHOUGH TRULY DRY/COOL AIR NEVER QUITE MAKES IT THIS FAR SOUTH. NEW 00Z GFS IS ACTUALLY KEEPING DEEP MOISTURE/PCPN ALONG EXTREME SOUTHERN BORDER THRU MIDWEEK...BUT NOT GOING FOR IT YET. CANADIAN BUILDS THE SFC RIDGE A LITTLE FURTHER SOUTH AND KEEPS IT DRY. BUMPED UP CLOUDINESS ACROSS THE SOUTH FOR THAT PD. AVIATION... SFC TROUGH ALONG THE BLUE RIDGE PRODUCED LOCALLY HEAVY DOWNPOURS OF 1-3 INCHES OF RAIN THIS AFTN. THESE STORMS QUICKLY DIMINISHED AFTER SUNSET. IFR VIS CONDITIONS FOR LOCATIONS ALONG AND WEST OF THE BLUE RIDGE EARLY THIS MORNING...MVFR EAST. FOG LIFTING TO STRATUS BY MID MORNING THEN SCATTERING OUT DURING THE AFTN. SFC TROUGH LINGERING ALONG THE BLUE RIDGE TO GIVE ANOTHER OPPORTUNITY FOR AFTN CONVECTION. CONFUSING SCENARIO WITH APPROACHING FRONT FROM THE WEST AND TS GASTON TO THE SE. SUBSIDENCE AND MOISTURE ROBBING FROM TS COULD RENDER MAJORITY OF THE AREA DRY WHILE EXTREME WESTERN CWA MAY SEE SOME CONVECTION BEING NEAR THE FRONT. WITH LOW CONFIDENCE...WILL LEAVE TEMPO TSRA LATE IN THE AFTN/EARLY EVENING. && && .RNK WATCHES/WARNINGS/ADVISORIES... NC...NONE. VA...NONE. WV...NONE. && $$ AVIATION (UPDATE)...JJ