Special Weather Statement, NWS Atlanta, GA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
345 PM EDT WED AUG 7 2013

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
COMBINATION OF SHORTWAVE...DIFFLUENT FLOW ALOFT AND PW/S OVER 2
INCHES LED TO AN ACTIVE MORNING ACROSS THE CWA. ACTIVITY IS EXPECTED
THROUGH THIS AFTERNOON INTO THE EVENING. COMPLEX OF STORMS IN TN IS
EXPECTED TO PUSH INTO NW GEORGIA...BUT DECREASE IN INTENSITY
QUICKLY. FLOODING AND WET MICROBURSTS CONTINUE TO BE THE MAIN
THREATS THROUGH TONIGHT AND AGAIN ON THURSDAY. GUIDANCE IS IN GOOD
AGREEMENT THAT CONVECTION WILL DECREASE AFTER SUNSET HOWEVER
DIFFERENCES EXIST AS WE MOVE INTO THE SECOND HALF OF THE NIGHT. GFS
BRINGS ANOTHER SHORTWAVE INTO NW GEORGIA AROUND 06Z WHILE THE ECMWF
IS SLOWER AND FURTHER NORTH WITH THIS DISTURBANCE. THINK WITH
DIFFLUENT FLOW STILL IN PLACE AND NEARING SHORTWAVE THAT COULD SEE
ACTIVITY FIRE UP AGAIN BEFORE SUNRISE ACROSS NORTH GEORGIA. THE
CAVEAT TO ALL OF THIS IS THE MODELS HAVE NOT BEEN HANDLING THE
SITUATION WELL RECENTLY. STILL UNCERTAINTY IN THE FORECAST FOR
THURSDAY. MAY STILL HAVE THE INFLUENCE OF THE SHORTWAVE FOR PART OF
THE DAY...HOWEVER THE UPPER RIDGE STRENGTHENS INTO THE CWA AND THUS
THE AREA LOSES THE NW FLOW THAT HAS BEEN SO PREDOMINATE. IN
ADDITION...THE BETTER UPPER LEVEL DIFFLUENCE IS LOST BY THE AFTERNOON.
ON THE OTHER HAND...PW/S REMAIN ABOVE NORMAL WITH NEAR 2 INCH VALUES
EXPECTED AGAIN ON THURSDAY...SO A WELL SATURATED ATMOSPHERE IS STILL
IN PLACE. THINK THE FOCUS FOR THURSDAY THOUGH WILL BE NORTH GEORGIA
AGAIN SO HAVE CARRIED LIKELY ACROSS MUCH OF THE AREA AND THEN CHANCE
ACROSS CENTRAL GEORGIA. SHOULD SEE A LULL IN ACTIVITY AGAIN THURSDAY
NIGHT. FOR MORE INFORMATION ABOUT POTENTIAL RAINFALL AND HYDROLOGY
IMPACTS SEE THE HYDRO SECTION.

11

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
12Z MODEL RUN SHOWED NO SIGNIFICANT CHANGES TO THE PREVIOUS MEDIUM
RANGE MODEL TRENDS. I HAVE MADE NO SIGNIFICANT CHANGES TO THE
EXISTING EXTENDED FORECAST GRIDS. PLEASE SEE THE PREVIOUS LONG TERM
FORECAST DISCUSSION BELOW.

20

PREVIOUS LONG TERM DISCUSSION/THURSDAY NIGHT THROUGH TUESDAY/

UPPER RIDGE WILL CONTINUE ANCHORED ACROSS THE SOUTHERN PLAINS WITH A
SERIES OF UPPER SHORT WAVES MOVING ACROSS THE STATE. HAVE KEPT MAINLY
CHANCE POPS DURING THE DAY AND CHANCE OR SLIGHT CHANCE OVERNIGHT.
HOWEVER FOR SATURDAY LOOKS LIKE A FRONTAL BOUNDARY WILL DRIFT INTO
NORTH GEORGIA AND STALL FOR A DAY OR TWO. SO HAVE INCLUDED LIKELY
POPS FOR NORTH GEORGIA ON SATURDAY. UPPER FLOW TRANSITIONS TO A
TROUGH OVER THE EASTERN STATES BY THE FIRST OF THE WEEK. SOME DRYING
IS INDICATED FOR NORTH GEORGIA MONDAY AND TUESDAY...BUT NOT ENOUGH TO
REMOVE POPS ALTOGETHER. TEMPERATURES LOOK SEASONAL WITH MID TO UPPER
80S NORTH TO LOW AND MID 90S SOUTH.

41

&&

.HYDROLOGY...
FLOODING CONTINUES ACROSS PARTS OF NORTH GEORGIA. MORE RAIN IS
POSSIBLE ACROSS THESE ALREADY FLOODED AREAS THROUGH THIS EVENING.
WITH ANOTHER DISTURBANCE POSSIBLY AFFECTING THE STATE AGAIN
BY THURSDAY MORNING...ADDITIONAL RAINFALL IS EXPECTED AGAIN ON
THURSDAY. ALTHOUGH WIDESPREAD AMOUNTS OF A HALF INCH TO AN INCH ARE
EXPECTED THROUGH THURSDAY AFTERNOON...ISOLATED HIGHER AMOUNTS ARE
POSSIBLE. THE FLASH FLOOD WATCH CONTINUES TO BE IN EFFECT UNTIL 8AM
THURSDAY. HAVE OPTED NOT EXTEND IT TEMPORALLY AT THIS POINT DUE TO
UNCERTAINTY IN THE FORECAST...BUT IT IS A DISTINCT POSSIBILITY THAT
THE FLOOD WATCH WILL NEED TO BE EXTENDED UNTIL THURSDAY AFTERNOON
ACROSS PARTS OF NORTH GEORGIA.

11

&&

AVIATION...
18Z UPDATE...
CONVECTION CONTINUES THIS AFTERNOON...BUT TIMING AT THE TAF SITES
IS VERY HARD TO TIME. HAVE CARRIED TEMPO TSRA THIS AFTERNOON
EVERYWHERE BUT MCN...BUT SO FAR TS HAS BEEN MORE SCT. WINDS AT ATL
ARE ON THE SSW SIDE HOWEVER SHOULD SHIFT BACK TO THE SSW BY LATE
AFTERNOON. IN ADDITION...SHOULD SEE CIGS IMPROVE THIS AFTERNOON
FROM LOW MVFR INTO HIGH MVFR OR LOW VFR.

//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON VSBYS. LOW CONFIDENCE ON CIGS...WIND
DIRECTION AND TIMING OF SHRA/TSRA.

11

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          70  88  72  90 /  40  50  30  30
ATLANTA         71  87  73  89 /  40  40  30  30
BLAIRSVILLE     69  81  68  86 /  60  70  40  40
CARTERSVILLE    71  87  72  90 /  50  60  30  40
COLUMBUS        74  92  74  93 /  40  40  30  30
GAINESVILLE     71  85  72  88 /  50  60  30  40
MACON           71  90  73  93 /  40  30  30  30
ROME            72  88  72  91 /  60  70  30  40
PEACHTREE CITY  70  87  72  90 /  40  40  30  30
VIDALIA         73  92  74  93 /  30  30  20  30

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR THE FOLLOWING
ZONES: BANKS...BARROW...BARTOW...BUTTS...CARROLL...CATOOSA...
CHATTOOGA...CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...DADE...
DAWSON...DEKALB...DOUGLAS...FANNIN...FAYETTE...FLOYD...FORSYTH...
GILMER...GORDON...GREENE...GWINNETT...HALL...HARALSON...HEARD...
HENRY...JACKSON...JASPER...LAMAR...LUMPKIN...MADISON...
MERIWETHER...MORGAN...MURRAY...NEWTON...NORTH FULTON...OCONEE...
OGLETHORPE...PAULDING...PICKENS...PIKE...POLK...PUTNAM...
ROCKDALE...SOUTH FULTON...SPALDING...TALIAFERRO...TOWNS...
TROUP...UNION...WALKER...WALTON...WHITE...WHITFIELD...WILKES.

&&

SHORT TERM...11
LONG TERM....20
AVIATION...11

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
631 AM EDT WED AUG 7 2013

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-081045-
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-
631 AM EDT WED AUG 7 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH AND CENTRAL GEORGIA.

.DAY ONE...TODAY AND TONIGHT...

A FLASH FLOOD WATCH IS IN EFFECT THROUGH THURSDAY MORNING FOR
NORTH GEORGIA.

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY
AND TONIGHT AS AN UPPER LEVEL DISTURBANCE MOVES SOUTH ACROSS THE
REGION. THE PRIMARY WEATHER HAZARD WILL BE HEAVY RAINFALL WITH
POSSIBLE LOCAL FLASH FLOODING. RAINFALL RATES OF ONE TO TWO INCHES
PER HOUR ARE POSSIBLE WITHIN THE WATCH AREA. OTHER HAZARDS INCLUDE
GUSTY WINDS AND FREQUENT LIGHTNING. ISOLATED STORMS COULD BECOME
SEVERE. ANY SEVERE THUNDERSTORM THAT DEVELOPS WILL HAVE THE
POTENTIAL TO PRODUCE DAMAGING WIND GUSTS OF 60 MPH OR GREATER.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...

SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE EACH DAY THROUGH THE
WEEK. THUNDERSTORMS WILL CONTINUE TO HAVE THE POTENTIAL TO PRODUCE
LOCALLY HEAVY RAINFALL...WHICH COULD CAUSE LOCALIZED FLOODING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT REQUESTED BUT SPOTTERS ARE ENCOURAGED
TO SUBMIT REPORTS OF SEVERE WEATHER THROUGH THE WEB BY GOING TO
WEATHER.GOV/ATLANTA.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
340 PM EDT WED AUG 7 2013

GAZ012-072045-
340 PM EDT WED AUG 7 2013

...SIGNIFICANT WEATHER ADVISORY FOR HEAVY RAIN IN GORDON COUNTY UNTIL
445 PM EDT...

AT 337 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM WITH HEAVY RAIN OVER REDBUD...MOVING NORTHEAST
AT 5 MPH. ADDITIONAL RAINFALL AMOUNTS OF UP TO 1 INCH ARE POSSIBLE
WITH THIS STORM.

RUNOFF FROM THESE STORMS WILL CAUSE MINOR FLOODING OF SMALL CREEKS
AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES ACROSS
GORDON COUNTY...INCLUDING AREAS AROUND OOSTANAULA...CALHOUN...
SONORAVILLE...FAIRMOUNT...SUGAR VALLEY...RESACA...REDBUD...RANGER...
AUDUBON AND OAKMAN. ADDITIONALLY...COUNTRY ROADS AND FARMLANDS ALONG
THE BANKS OF CREEKS AND STREAMS ARE SUBJECT TO MINOR FLOODING.

&&

LAT...LON 3460 8503 3460 8480 3457 8468 3443 8468
      3441 8479 3441 8505
TIME...MOT...LOC 1940Z 208DEG 5KT 3454 8488

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
353 PM EDT WED AUG 7 2013

GAZ001>005-072100-
353 PM EDT WED AUG 7 2013

...SIGNIFICANT WEATHER ADVISORY FOR HEAVY RAIN AND WINDS GUSTING TO
35 MPH IN WHITFIELD...WALKER...MURRAY...CATOOSA AND DADE COUNTIES
UNTIL 500 PM EDT...

AT 349 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS FROM BOYNTON TO 6 MILES NORTHWEST OF RISING
FAWN...MOVING SOUTHEAST AT 20 MPH.

THESE STORMS HAVE THE POTENTIAL TO PRODUCE FREQUENT CLOUD TO GROUND
LIGHTNING AND WIND GUSTS TO 35 MPH AS THEY MOVE ACROSS
WHITFIELD...WALKER...MURRAY...CATOOSA AND DADE COUNTIES THROUGH 500
PM EDT. SOME LOCATIONS IN THE PATH OF THESE STORMS INCLUDE
BOYNTON...INDIAN SPRINGS...GRAYSVILLE...FORT
OGLETHORPE...CHATTANOOGA VALLEY...FAIRVIEW...CHICKAMAUGA...CLOUDLAND
CANYON STATE PARK...BLUE SPRING...RINGGOLD...SALEM...COOPER
HEIGHTS...RISING FAWN...BEAUMONT AND ROCK SPRING. HEAVY DOWNPOURS
WILL CAUSE PONDING OF WATER ON ROADWAYS.

&&

LAT...LON 3478 8483 3466 8506 3460 8554 3484 8558
      3499 8517 3499 8468
TIME...MOT...LOC 1953Z 304DEG 16KT 3492 8515 3485 8538
          3480 8559

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
418 PM EDT WED AUG 7 2013

GAZ039-051-061-062-072115-
418 PM EDT WED AUG 7 2013

...SIGNIFICANT WEATHER ADVISORY FOR HEAVY RAIN IN WILKES...WARREN...
TALIAFERRO AND HANCOCK COUNTIES UNTIL 515 PM EDT...

AT 417 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS WITH HEAVY RAIN FROM FLORAL HILL TO
SPARTA...MOVING EAST AT 10 MPH. RAINFALL AMOUNTS OF 1 TO 2 INCHES
ARE POSSIBLE WITH THESE STORMS.

RUNOFF FROM THESE STORMS WILL CAUSE MINOR FLOODING OF SMALL CREEKS
AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES ACROSS
WILKES...WARREN...TALIAFERRO AND HANCOCK COUNTIES...INCLUDING AREAS
AROUND SPARTA...FLORAL HILL...WASHINGTON...ALEXANDER STEPHENS PARK...
SANDY CROSS...SPRINGFIELD...FICKLIN...CRAWFORDVILLE...SPRINGFIELD...
METASVILLE...LUNDBERG...CULVERTON...POWELTON AND ROCKY CREEK FIRE
DEPT.. ADDITIONALLY...COUNTRY ROADS AND FARMLANDS ALONG THE BANKS OF
CREEKS AND STREAMS ARE SUBJECT TO MINOR FLOODING.

&&

LAT...LON 3363 8260 3360 8264 3346 8258 3341 8254
      3331 8261 3326 8272 3325 8307 3343 8307
      3349 8298 3356 8300 3388 8257 3380 8258
      3365 8249
TIME...MOT...LOC 2018Z 270DEG 7KT 3382 8255 3360 8282
          3352 8296 3329 8297

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
444 PM EDT WED AUG 7 2013

GAZ072-073-082>084-094-095-072145-
444 PM EDT WED AUG 7 2013

...SIGNIFICANT WEATHER ADVISORY FOR HEAVY RAIN IN TWIGGS...PEACH...
JONES...WILKINSON...BALDWIN...BIBB AND HOUSTON COUNTIES UNTIL 545 PM
EDT...

AT 440 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS WITH HEAVY RAIN FROM BROWNS CROSSING TO HOUSTON
LAKE THE LINE OF THUNDERSTORMS WERE NEARLY STATIONARY. RAINFALL
AMOUNTS OF 1 TO 2 INCHES ARE LIKELY WITH THESE STORMS.

RUNOFF FROM THESE STORMS WILL CAUSE MINOR FLOODING OF SMALL CREEKS
AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES ACROSS
TWIGGS...PEACH...JONES...WILKINSON...BALDWIN...BIBB AND HOUSTON
COUNTIES...INCLUDING AREAS AROUND HOUSTON LAKE...WESLEYAN...LAKE
TOBESOFKEE...ARKWRIGHT...SKIPPERTON...RUTLAND...PAYNE CITY...MACON...
LAKEWOOD...BYRON...CLINTON...HADDOCK...GRAY...CENTERVILLE AND MIDDLE
GEORGIA REGIONAL AIRPORT. ADDITIONALLY...COUNTRY ROADS AND FARMLANDS
ALONG THE BANKS OF CREEKS AND STREAMS ARE SUBJECT TO MINOR FLOODING.

&&

LAT...LON 3247 8375 3268 8379 3269 8377 3269 8372
      3273 8380 3287 8382 3313 8338 3313 8314
      3288 8332 3275 8349 3246 8349
TIME...MOT...LOC 2043Z 270DEG 2KT 3306 8339 3281 8366
          3255 8366

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
500 PM EDT WED AUG 7 2013

GAZ005-007-012-013-020-021-072145-
500 PM EDT WED AUG 7 2013

...SIGNIFICANT WEATHER ADVISORY FOR HEAVY RAIN AND WINDS GUSTING TO
35 MPH IN PICKENS...MURRAY...BARTOW...CHEROKEE...GILMER AND GORDON
COUNTIES UNTIL 545 PM EDT...

AT 457 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS WITH HEAVY RAIN FROM RAMHURST TO SUGAR
VALLEY...MOVING SOUTHEAST AT 30 MPH. RAINFALL AMOUNTS OF UP TO 1
INCH ARE POSSIBLE WITH THESE STORMS.

THESE STORMS HAVE THE POTENTIAL TO PRODUCE FREQUENT CLOUD TO GROUND
LIGHTNING AND WIND GUSTS TO 35 MPH AS THEY MOVE ACROSS
PICKENS...MURRAY...BARTOW...CHEROKEE...GILMER AND GORDON COUNTIES
THROUGH 545 PM EDT. SOME LOCATIONS IN THE PATH OF THESE STORMS
INCLUDE NICKELSVILLE...RESACA...SUGAR VALLEY...NORTH GEORGIA
SPEEDWAY...CHATSWORTH...AUDUBON...RAMHURST...CALHOUN...OAKMAN...REDBU
D...CARTERS...TAILS CREEK...RANGER...SONORAVILLE AND ROUNDTOP. HEAVY
DOWNPOURS WILL CAUSE PONDING OF WATER ON ROADWAYS.

THE HIGH RAIN TOTALS SEEN FROM THIS MORNING HAS RESULTED IN
EXTREMELY SATURATED SOILS FOR AREA TREES. THIS WILL ALLOW THESE
TREES TO FALL DUE TO WINDS MUCH LOWER THAN IN A TYPICAL SEASON...AS
LOW AS 30 MPH IN SOME CASES.

&&

LAT...LON 3468 8433 3441 8439 3431 8481 3454 8507
      3461 8493 3477 8477
TIME...MOT...LOC 2059Z 296DEG 24KT 3471 8474 3457 8482
          3452 8502

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
504 PM EDT WED AUG 7 2013

GAZ011-072200-
504 PM EDT WED AUG 7 2013

...SIGNIFICANT WEATHER ADVISORY FOR HEAVY RAIN AND WINDS GUSTING TO
35 MPH IN CHATTOOGA COUNTY UNTIL 600 PM EDT...

AT 501 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS WITH HEAVY RAIN FROM 6 MILES NORTHEAST OF
CLOUDLAND TO 12 MILES WEST OF MENLO...MOVING SOUTHEAST AT 10 MPH.
RAINFALL AMOUNTS OF UP TO 1 INCH ARE LIKELY WITH THESE STORMS.

THESE STORMS HAVE THE POTENTIAL TO PRODUCE FREQUENT CLOUD TO
GROUND LIGHTNING AND WIND GUSTS TO 35 MPH AS THEY MOVE ACROSS
CHATTOOGA COUNTY THROUGH 600 PM EDT. SOME LOCATIONS IN THE PATH OF
THESE STORMS INCLUDE CLOUDLAND...MENLO...TRION...CHATTOOGAVILLE...
JAMES H. FLOYD STATE PARK...LYERLY...BERRYTON AND SUMMERVILLE. HEAVY
DOWNPOURS WILL CAUSE PONDING OF WATER ON ROADWAYS.

&&

LAT...LON 3459 8533 3450 8519 3431 8544 3430 8547
      3453 8552 3459 8553
TIME...MOT...LOC 2103Z 327DEG 8KT 3459 8544 3450 8559
          3444 8567