000 FXUS63 KPAH 091130 AFDPAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 630 AM CDT THU SEP 9 2010 .UPDATE... UPDATED FOR 12Z AVIATION FORECAST DISCUSSION. && .DISCUSSION... MAIN CONCERNS ARE POPS THROUGH SATURDAY NIGHT. A SECONDARY CONCERN IS TEMPERATURES WITH LOTS OF CLOUD/PRECIPITATION AROUND. IR SATELLITE IMAGERY SHOWS THAT THE COLDEST CLOUDS AND HEAVY PRECIPITATION LOCATED OVER EASTERN OKLAHOMA FOR MUCH OF THE NIGHT...ARE MOVING PRIMARILY TO THE EAST INTO NORTHWEST ARKANSAS. UNFORTUNATELY...THE NAM AND GFS STILL ARE PUSHING IT NORTH AND THEN WEST. IN ADDITION THEY ARE TOO SLOW WITH THE EASTWARD PROGRESS. THE ECMWF HAS BEEN CONSISTENTLY FASTER AND FARTHER SOUTH WITH THE TRACK...AND HPC QPF GUIDANCE HAS CONSISTENTLY BEEN EVEN FARTHER SOUTH. DECIDED TO DISREGARD THE NAM AND GFS AND FOLLOW HPC QPF FOR TIMING/LOCATION OF POPS THROUGH SATURDAY NIGHT. LIGHTNING ACTIVITY HAS ALMOST COMPLETELY STOPPED WITH THE SYSTEM AS OF 08Z...AND SEE LITTLE REASON FOR BETTER INSTABILITY TO DEVELOP OVER OUR REGION. WILL MENTION A SLIGHT CHANCE OF THUNDER IN THE WEST THIS AFTERNOON...BUT WILL ONLY MENTION SHOWERS THIS MORNING AND TONIGHT. THUNDER CHANCES RETURN FRIDAY THROUGH SATURDAY...AS THE TROPICAL AIRMASS IS PUSHES EAST OF THE AREA. LIGHT RAIN WILL BE FALLING OVER WESTERN PORTIONS OF SOUTHEAST MISSOURI SHORTLY...AND THE HEAVIER RAINFALL WILL BE THERE BY 18Z. DESPITE INITIALLY DRY LOW-LEVELS /BELOW 850MB/...SIGNIFICANT RAINS WILL OVERSPREAD AREAS WEST OF THE I-57/I-24 CORRIDOR THROUGH THE AFTERNOON...AND THE REMAINDER OF THE AREA THIS EVENING. BACK EDGE OF THE HEAVIER RAINS WILL PUSH THROUGH SOUTHEAST MISSOURI OVERNIGHT TONIGHT...AS HEAVIEST RAINS IMPACT THE PENNYRILE REGION OF WEST KENTUCKY. EXPECT THAT THE TROPICAL AIRMASS/RAINS WILL EXIT THE AREA FRIDAY MORNING...BUT A WARM FRONT WILL TRY TO GET ESTABLISHED FROM SOUTHERN ILLINOIS THROUGH THE PENNYRILE REGION FRIDAY AFTERNOON AND NIGHT. THIS MAY PROVIDE A FOCUS FOR CONVECTIVE DEVELOPMENT OVER THE NORTHEAST HALF OF THE AREA LATE FRIDAY AND FRIDAY NIGHT. THE COLD FRONT IS STILL ON SCHEDULE TO BRING A CHANCE OF WIDESPREAD THUNDERSTORMS...SOME POSSIBLY STRONG OR SEVERE...TO THE REGION SATURDAY. DRY FORECAST STILL LOOKS GOOD BEYOND SATURDAY EVENING. TRIED TO FIT HIGH TEMPERATURE FORECAST TO THE PRECIPITATION FORECAST AS WELL AS POSSIBLE...GIVEN THE MODELS ARE NOT HANDLING THE SYSTEM WELL. WITH THE EXTREME DEPTH OF MOISTURE OVER THE AREA TODAY WOULD NOT BE SURPRISED IF SOME LOCATIONS REMAIN IN THE LOWER 70S. ALTHOUGH WIDESPREAD 1-2 INCH RAINFALL AMOUNTS ARE FORECAST THROUGHOUT THE QUAD STATE OVER A 24 HOUR PERIOD...6 HOUR FLASH FLOOD GUIDANCE VALUES ARE 3-4 INCHES IF NOT HIGHER. DESPITE THE TROPICAL RAIN/SHOWERS EXPECTED...THE EXTREMELY DRY SOIL CONDITIONS SHOULD ALLOW MOST AREAS TO DRAIN SUFFICIENTLY. THEREFORE...WILL NOT ISSUE A FLASH FLOOD WATCH AT THIS TIME. BEYOND SATURDAY NIGHT MADE ONLY COSMETIC CHANGES TO FIT IN BETTER WITH NEIGHBORS. && .AVIATION... WE SHOULD CONTINUE TO SEE THE ARRIVAL OF MOISTURE FROM WEST TO EAST DURING THE DAY TODAY. PRECIP SHOULD ARRIVE AT KCGI/KPAH THIS MORNING...BUT TAKE A WHILE TO REACH KEVV/KOWB...MORE LIKELY IN THE EARLY EVENING. LIGHT EAST TO SOUTHEAST WINDS AROUND 4-8 KTS EXPECTED. TIMING OF THE RAINFALL IS THE BIGGEST ISSUE AT THIS POINT AND ALSO ANY THREAT FOR MVFR OR LOWER CIGS/VSBYS TO DEAL WITH. HARD TO PINPOINT WHEN THIS MAY OCCUR...BUT WILL OBVIOUSLY BE ASSOCIATED WITH THE HEAVIEST DOWNPOURS...WHICH IS CHALLENGING TO FORECAST AT THIS POINT. && .PAH WATCHES/WARNINGS/ADVISORIES... KY...NONE. MO...NONE. IL...NONE. IN...NONE. && $$ NWS PAH Office Area Forecast Discussion