000 FXUS62 KFFC 100009 AAB AFDFFC AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 809 PM EDT THU JUL 9 2009 .UPDATE... QUICK UPDATE TO TWEAK POPS AND SKY DOWN A LITTLE. REST OF FCST LOOKS GOOD. OBSERVED AND MODEL FCST LOW LEVEL MOISTURE QUITE A BIT LOWER OVERNIGHT THAN LAST FEW DAYS SO HAVE REMOVED TSRA FROM FCST AFTER MIDNIGHT. SNELSON && .PREV DISCUSSION... /ISSUED 630 PM EDT THU JUL 9 2009/ SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... PRIMARY CONCERN IN THE SHORT TERM PERIOD IS COVERAGE AND INTENSITY OF TSRA REST OF THE AFTERNOON AND TONIGHT. SLOW MOVING UPPER TROUGH MOVING THROUGH THE REGION. TROUGH MOSTLY RESPONSIBLE FOR UNSEASONABLY COOL LOW LEVEL THICKNESS AND PERSISTENT LOW CLOUDS. TEMPS HAVE REMAINED A LITTLE BELOW ALREADY COOL FORECAST TEMPS THIS AFTERNOON...HOWEVER MORNING SOUNDING MODIFIED FOR CURRENT CONDITIONS 80/66 SHOWS 1600 J/KG SBCAPE. PERHAPS WITH INCREASED BREAKS IN STRATUS...MORE DIABATICALLY GENERATED BOUNDARIES WILL HELP ADDITIONAL CONVECTION TO DEVELOP. VERTICAL WIND SHEAR IS ALSO SIGNIFICANTLY WEAKER THAN YESTERDAY. ANY STORMS THAT DEVELOP WILL BE DISORGANIZED WITH LITTLE THREAT OTHER THAN LIGHTNING...LOCALLY HEAVY RAIN AND WIND GUSTS TO 40 MPH. AS UPPER TROUGH MOVES OUT OF THE REGION...UPPER RIDGE TRIES TO BUILD IN FROM THE WEST RESULTING...TEMPORARILY IN WEAK SUBSIDENCE AND SLIGHTLY DRIER REGIME MOVING IN. SFC BOUNDARY SHOULD PRETTY MUCH WASH OUT WITH SFC RIDGING EAST OF APPALACHIANS PUSHING INTO NE GA. OVERALL...SHOULD SEE DECREASE IN COVERAGE/ LIKELIHOOD OF TSRA. FEEL UNCOMFORTABLE REMOVING POPS AS INDICATED BY MAV/MET POP GUIDANCE FOR FRIDAY INTO THIS WEEKEND. HAVE BUMPED UP A BIT WITH 10-20 AFTERNOON/EVENING POPS...HIGHER OVER MIDDLE GA CLOSER TO SEA BREEZE INITIATED ACTIVITY. TEMPS SHOULD CREEP BACK TO NORMAL ESP THIS WEEKEND. USED 30 DAY BIAS-ADJUSTED MAV/MET BLEND WITH 2-3 DEG WARM BIASES FOR MAXT NOTED AT KRMG...KCSG AND KMCN AND 3-4 DEG COLD BIASES FOR MINT AT KFFC...KPDK...KVPC AND KFTY. LONG TERM /SUNDAY THROUGH THURSDAY/... WESTERLIES REMAIN PERILOUSLY CLOSE TO THE AREA AND SHORT WAVE PROGGED TO PUSH FRONT TOWARD THE STATE WITH WNW FLOW ALOFT ON SUNDAY BUT THEN HANG UP THERE. GFS/GEFS/ECM INDICATE MOST LIKELY TIME FOR PRECIP WOULD BE EARLY NEXT WEEK AS WESTERLIES DIP INTO NORTH GA AND THE CAROLINAS. DEATH RIDGE OVER THE SOUTHERN ROCKIES AND PLAINS STILL ATTEMPTING TO PUSH INTO THE DEEP SOUTH AND SOUTHEAST LATER IN THE WEEK BUT NOT SO MUCH AS TO IMPACT WEATHER HERE GREATLY. NO BIG DIFFERENCES BETWEEN MED RANGE MODELS SO CHC POPS LOOK GOOD. EL NINO STILL APPEARS TO BE INFLUENCING LARGE SCALE PATTERN OVER THE CONUS THIS SUMMER. SNELSON AVIATION... IMMEDIATE CONCERN IS THREAT FOR CONVECTION THIS EVENING. THREAT APPEARS TO BE WANING...BUT AM CONCERNED THAT ANY OUTFLOW BOUNDARIES FROM CURRENT UPSTREAM ACROSS NW GA MAY REACH THE ATL AREA IN THE 00Z-03Z TIME FRAME AND GENERATE ADDITIONAL TSRA. PLAN TO INCLUDE IN TAF...BUT MAY AMEND AND REMOVE SHORTLY AFTER ISSUANCE IF THREAT DOES NOT MATERIALIZE. NEXT CONCERN IS POTENTIAL FOR LOW CLOUDS AND FOG FRI MORN. WITH NE FLOW IN PLACE...THANKS TO SWWD MOVING MID-ATLANTIC HIGH...AND VERY MOIST UPSTREAM GROUND AND CURRENT CLOUD COVER...LEADS ME TO BELIEVE THAT THERE WILL BE LOW CLOUDS AND FOG EARLY FRI. WILL INCLUDE LOW MVFR CIGS AND MVFR VSBY FOR 10Z-14Z TIME FRAME AT MOST TAF SITES EARLY FRI. OTHERWISE...REMAINDER OF TAF VALID PERIOD LOOKS VFR. UPPER-LEVEL RIDGE NOSING IN FROM THE WEST AND DRIER SFC AIR MASS ADVECTING SW INTO THE AREA FRI-SAT...SHOULD LIMIT CONVECTION TO VERY ISOLD NEXT TWO AFTNS. DO NOT PLAN TO INCLUDE MENTION OF CONVECTION FRI...WITH POSSIBLE EXCEPTION OF CSG...CLOSER TO BACKDOOR FRONTAL BOUNDARY. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 67 88 66 92 67 / 20 10 10 10 10 ATLANTA 67 87 68 89 69 / 20 10 10 10 10 BLAIRSVILLE 61 79 62 83 63 / 20 20 10 20 20 CARTERSVILLE 66 88 66 91 66 / 20 10 10 10 10 COLUMBUS 70 88 70 93 69 / 20 20 10 20 10 GAINESVILLE 66 85 66 89 68 / 20 10 10 10 10 MACON 68 89 66 91 67 / 20 20 10 10 10 ROME 66 89 67 91 68 / 20 10 10 10 10 PEACHTREE CITY 65 88 64 90 66 / 20 10 10 10 10 VIDALIA 67 88 67 91 68 / 30 30 10 20 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 13