489 
FXUS62 KFFC 050736
AFDFFC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
336 AM EDT FRI JUL 5 2013

.SHORT TERM /TODAY THROUGH SATURDAY/...
HIGH AMPLITUDE UPPER TROUGH OVER THE CENTER OF THE COUNTRY PLUS VERY 
STRONG UPPER HIGH OVER THE WESTERN ATLANTIC CONTINUE TO FUNNEL A 
VERY MOIST AIRMASS INTO THE SOUTHEAST...WITH PW VALUES REMAINING 
QUITE HIGH FOR THIS TIME OF YEAR /1.85 ON 00Z KFFC SOUNDING...MODEL 
SOUNDINGS HOVERING BETWEEN 1.8 AND 2.0 INCHES THROUGH THE 
SHORT-TERM/. A BIT OF DRY AIR...VERY NOTICEABLE AT 850MB WITH KFFC 
DEWPOINT AT 00Z AT ONLY 9C WHEREAS KBMX AT 15C...HAS NOSED INTO THE 
SOUTHEAST AS THE MOISTURE AXIS SHIFTED FARTHER WEST. VERY LITTLE 
CHANGE TO THIS SYSTEM THROUGH THE SHORT-TERM EXCEPT THAT ALL MODELS 
ACTUALLY CLOSE OFF THE LOW BY SATURDAY MORNING. AT THAT POINT IT IS 
PROGGED TO START SLOWLY LIFTING...THE ECMWF IS A LITTLE FASTER WITH 
THIS THAN THE GFS. GIVEN THE LACK OF ANY SIGNIFICANT HEIGHT RISES OR 
FALLS ON THE 00Z 500MB ANALYSIS...AM INCLINED TO THINK THE SLOWER 
SOLUTION MIGHT BE BETTER. THIS IS A BIGGER DIFFERENCE FOR THE FIRST 
PART OF THE EXTENDED THAN FOR THE NEXT 36 HOURS THOUGH.

FOR TODAY...A SHORTWAVE ROUNDING THE BASE OF THE TROUGH AS SEEN ON 
00Z UA ANALYSIS AND WATER VAPOR LOOP SHOULD LIFT INTO THE SOUTHEAST 
TODAY...PUSHING THE HIGH PW AXIS A LITTLE FARTHER EAST AND INTO THE 
WESTERN PORTION OF THE STATE. ADD TO THIS THE OROGRAPHIC LIFT ACROSS 
NORTH GEORGIA AND EXPECT THE SWATH OF HEAVY RAIN TO GENERALLY BE ON 
THE WESTERN SIDE OF THE STATE AND THEN SPREADING EAST ACROSS TO THE 
NORTH GEORGIA MOUNTAINS. NAM AND GFS HAVE SIGNIFICANT DIFFERENCES IN 
MUCAPE VALUES THIS AFTERNOON...IN AN ODD REVERSAL GFS CLIMBS CAPES 
TO OVER 1500 J/KG WHEREAS NAM KEEPS CAPES ESPECIALLY IN SOUTHEAST 
ZONES BETWEEN 500-1000 J/KG. WITH WIDESPREAD CLOUD COVER AND VERY 
TROPICAL ENVIRONMENT...HAVE KEPT THUNDER TO SLIGHT CHANCE THIS 
MORNING AND CHANCE THIS AFTERNOON...THINK IT WILL BE MORE WIDESPREAD 
SHOWERS THAN THUNDER. NOT REALLY CONCERNED ABOUT SEVERE 
CHANCES...BUT AS WITH THE PAST FEW DAYS CANNOT RULE OUT BRIEF WIND 
GUSTS...AND IT CERTAINLY WILL NOT TAKE 50KT WINDS TO BRING DOWN 
TREES WITH SOILS THIS SATURATED. WE LOSE THE WEAK 0-1KM SHEAR THAT 
HAS BEEN IN PLACE OVER THE PAST FEW DAYS SO EXPECT EVEN LESS WEAK 
ROTATION TODAY THAN WE HAVE SEEN THE PAST FEW DAYS. ALSO...HIRES 
MODELS WANT TO DEVELOP CONVECTION ALONG THE SEABREEZE WORKING ITS 
WAY INLAND AGAIN. OVERALL VERY HARD TO SAY AT THIS POINT WHAT 
EXACTLY WILL HAPPEN THIS AFTERNOON AND EVENING SO ALONG THE WESTERN 
BORDER AND ACROSS NORTH GEORGIA WENT CATEGORICAL POPS...BUT KEPT IT 
TO HIGH CHANCE OR LIKELY ACROSS SOUTHEAST ZONES UNTIL WE GET A 
BETTER HANDLE ON TRENDS.

ON SATURDAY...AGAIN FOR THE MOST PART THE HIGH PW AND THUS HEAVY 
RAIN AXIS WILL REMAIN GENERALLY ACROSS ALABAMA...BUT KEPT THE TREND 
OF HIGH POPS ALONG THE GA/AL BORDER AND ACROSS THE NORTH GEORGIA 
MOUNTAINS. 

TEMPS WILL REMAIN WELL BELOW NORMAL /8-10 DEGREES IN GENERAL/ GIVEN 
WIDESPREAD CLOUD COVER. MOS NOT QUITE PICKING UP ON HOW COOL TEMPS 
HAVE BEEN AND 5-DAY BIASES FOR ALL SITES INDICATE WE HAVE BEEN A 
COUPLE OF DEGREES TOO WARM. STARTED WITH A BIAS-CORRECTED BLEND AND 
REDUCED TEMPS BY AN ADDITIONAL DEGREE OR TWO. STILL NOT REALLY IN 
DANGER OF MEETING RECORD LOW HIGHS THOUGH THE FORECAST HIGH FOR CSG 
IS ONLY A COUPLE OF DEGREES OFF /FOR TODAY...AHN 70...ATL 70...CSG 
78...MCN 75/. INTERESTING THAT THE FORECAST FOR ATL...FOR EXAMPLE... 
IS 21 DEGREES COOLER THAN THE HIGH LAST YEAR /WHICH SET A RECORD AT 
100 DEGREES/.

.HYDROLOGY...
WENT GENERALLY WITH HPC QPF VALUES WHICH KEEP PRECIP BETWEEN 1/2 TO 
3/4 INCH TODAY NORTH AND WEST...LESS SOUTHEAST...AND MAYBE ANOTHER 
1/4 TO 1/2 ON SATURDAY. WITH THAT...WILL KEEP FLASH FLOOD WATCH IN 
EFFECT THROUGH 00Z TONIGHT. WITH ANY CONVECTION THAT DEVELOPS... 
WITH SUCH HIGH PW VALUES IN PLACE...CANNOT RULE OUT ISOLATED FLASH 
FLOODING THROUGH THE SHORT-TERM ESPECIALLY IN THE NORTH GEORGIA 
MOUNTAINS AND ANY LOCATIONS WHERE STORMS TRAIN.

TDP

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...

THE EXTENDED PERIOD CONTINUES WET WITH PERSISTENT UPPER LOW OVER
THE MISSOURI VALLEY SPAWNING ADDITIONAL SHORTWAVE ENERGY SATURDAY
NIGHT. THIS UPPER SUPPORT ALONG WITH PWATS REMAINING WELL ABOVE 2
INCHES WILL ALLOW FOR LIKELY POPS EVEN INTO THE OVERNIGHT PERIOD
WITH HEALTHY AMOUNTS OF QPF IN THE .30 TO .50 RANGE FOR SIX HOUR
PERIODS. BY SUNDAY AFTERNOON...UPPER LOW WILL TRANSITION INTO THE
OHIO VALLEY WITH GFS DEPICTING UPPER TROUGH AXIS INTO NORTHERN
GEORGIA. WITH CONTINUED AMPLE MOISTURE...EXPECT CATEGORICAL POPS
GIVEN SHORTWAVE ENERGY AVAILABLE TO FUEL STORM DEVELOPMENT. 

AS LOW FINALLY KICKS OUT THROUGH MIDWEEK...MOISTURE AXIS PIVOTS
BUT REMAINS OVER THE NORTH GEORGIA PORTION. ALTHOUGH UPPER ENERGY
WILL NOT BE AS PREVALENT...SHOULD SEE MORE THAN ENOUGH INGREDIENTS
TO WARRANT HIGH END CHANCE TO LIKELY POPS THROUGH WEDNESDAY. GFS
INDICATES 48 HOUR TOTALS ENDING THU MORNING OF AN ADDITIONAL 2
INCHES FOR THE NORTHERN TIER WHICH WOULD CREATE ADDITIONAL FLOODING
CONCERNS PENDING WHAT TAKES PLACE THE NEXT FEW DAYS. 

BY LATE WED INTO THU...UPPER LOW OVER THE GULF BECOMES MORE OF A
PROMINENT FEATURE AS INFLUENCES OF ATLANTIC UPPER HIGH ABATE.
MEANWHILE...NORTHERN STREAM SHORTWAVE DIGS SOUTHWARD WITH A
SURFACE BOUNDARY ENTERING NORTH GEORGIA THU AFTERNOON. MOISTURE
POOLING ALONG THIS FEATURE WILL INCREASE POPS ONCE AGAIN AND WILL
CARRY HIGH MID RANGE POPS IN GRIDS FOR NOW.

GIVEN TIME OF YEAR...BOUNDARY DOES NOT MAKE IT VERY FAR INTO THE
FORECAST AREA BEFORE STALLING. ADDITIONAL SHORTWAVE ENERGY IN
DEVELOPING NORTHWEST FLOW ALOFT REGIME WILL KEEP POPS AT OR ABOVE
CLIMO THROUGH THE EXTENDED PERIOD WITH TEMPS AT OR BELOW NORMAL.

DEESE


&&


.AVIATION...
06Z UPDATE...
CONDITIONS GENERALLY LOW MVFR TO IFR ACROSS THE AREA EXCEPT AT
MCN...BUT INTERMITTENT HOLES ACROSS THE AREA WILL LEAD TO BRIEF
IMPROVING CONDITIONS. KEEP CIGS IFR MOST OF THE NIGHT NORTH...LOW
MVFR SOUTH. GENERALLY MVFR VSBY EXPECTED. EXPECT SHRA TO DEVELOP
AGAIN THROUGH THE MORNING...AND KEPT TREND OF PROB30 FOR AFTERNOON
TSRA WITH MVFR CIGS NORTH...POSSIBLY LOW VFR SOUTH THIS AFTERNOON
AND EARLY EVENING. EXPECT IFR TO MOVE BACK IN AFTER 06Z AND HAVE
TRENDED THAT WAY IN ATL TAF. SE TO SSE WINDS GENERALLY 5-10KT
THROUGH THE PERIOD.

//ATL CONFIDENCE...06Z UPDATE...
HIGH ON WINDS.
MEDIUM ON VSBY...CIGS AND TIMING.
HIGH ON OCCURRENCE OF AFTN TSRA...MEDIUM-LOW ON IMPACTS TO ATL.

TDP

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          82  69  84  71 /  90  60  70  40 
ATLANTA         79  70  80  71 / 100  70  80  50 
BLAIRSVILLE     75  65  76  67 / 100  80  90  60 
CARTERSVILLE    79  70  79  71 / 100  80  90  60 
COLUMBUS        80  71  83  74 / 100  60  80  50 
GAINESVILLE     78  68  79  70 / 100  70  80  50 
MACON           83  70  85  71 /  80  40  60  40 
ROME            78  70  80  72 / 100  90  90  60 
PEACHTREE CITY  79  70  80  71 / 100  60  80  50 
VIDALIA         87  72  88  72 /  40  30  40  20 

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR THE FOLLOWING ZONES: 
BALDWIN...BANKS...BARROW...BARTOW...BIBB...BLECKLEY...BUTTS...
CARROLL...CATOOSA...CHATTAHOOCHEE...CHATTOOGA...CHEROKEE...
CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...CRISP...DADE...
DAWSON...DEKALB...DODGE...DOOLY...DOUGLAS...EMANUEL...FANNIN...
FAYETTE...FLOYD...FORSYTH...GILMER...GLASCOCK...GORDON...
GREENE...GWINNETT...HALL...HANCOCK...HARALSON...HARRIS...HEARD...
HENRY...HOUSTON...JACKSON...JASPER...JEFFERSON...JOHNSON...
JONES...LAMAR...LAURENS...LUMPKIN...MACON...MADISON...MARION...
MERIWETHER...MONROE...MONTGOMERY...MORGAN...MURRAY...MUSCOGEE...
NEWTON...NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PEACH...
PICKENS...PIKE...POLK...PULASKI...PUTNAM...ROCKDALE...SCHLEY...
SOUTH FULTON...SPALDING...STEWART...SUMTER...TALBOT...
TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...TOWNS...TREUTLEN...
TROUP...TWIGGS...UNION...UPSON...WALKER...WALTON...WARREN...
WASHINGTON...WEBSTER...WHEELER...WHITE...WHITFIELD...WILCOX...
WILKES...WILKINSON.

&&

$$

SHORT TERM...TDP
LONG TERM....DEESE
AVIATION...TDP