Special Weather Statement, NWS Atlanta, GA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
155 AM EDT THU SEP 22 2011

.PREVIOUS DISCUSSION.../ISSUED AT 1038 PM EDT WED SEP 21 2011/...

UPDATE...

HAVE MADE SEVERAL ADJUSTMENTS TO POPS/WX/SKY GRIDS TO ACCOUNT FOR
CURRENT TRENDS. MAINLY LOWERED POPS ACROSS PORTIONS OF NORTH
GEORGIA AS BEST SURFACE CONVERGENCE IS GENERALLY SOUTH OF THE
I-20/I85 LINE. CLOUD COVER SHOULD REMAIN FAIRLY HIGH THROUGH THE
NIGHT. MAY SEE SOME FOG OR POSSIBLY DRIZZLE OVERNIGHT AS CEILINGS
LOWER...SO HAVE ADDED PATCHY FOG TO THE 06-12Z PERIOD.
OTHERWISE...MADE MINOR TWEAKS TO HOURLY TEMPS TO REFLECT CURRENT
TRENDS BUT NO MAJOR CHANGES. UPDATED ZONES WILL BE OUT SHORTLY.

25
&&

PREV DISCUSSION... /ISSUED 206 PM EDT WED SEP 21 2011/

SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
MODELS IN GOOD AGREEMENT THROUGH THE SHORT TERM. ALL KEEP HIGH
MOISTURE VALUES...HIGH PRECIPITABLE WATERS...AND INSTABILITY OVER
THE CWA UNTIL A H5 SHORTWAVE ROTATES AROUND THE UPPER LOW...
CURRENTLY OVER THE U.P. OF MICHIGAN...AND MOVES INTO THE TENNESSEE
VALLEY. THIS SHORT WAVE WILL FORCE THE SURFACE COLD FRONT ACROSS THE
CWA...HOWEVER THIS WILL NOT HAPPEN UNTIL FRIDAY NIGHT. UNTIL THEN
WILL NEED TO CONTINUE A CHANCE OF SHOWERS/TSTORMS. WITH A GOOD
TROPICAL CONNECTION...THERE WILL LIKELY BE ISOLATED HIGH PRECIP
AMOUNTS...SIMILAR TO LAST NIGHT WITH JONES COUNTY SEEING BETWEEN 6
AND 7 INCHES OF RAIN. TEMPS WILL REMAIN WARM THROUGH THE SHORT TERM
AND GUIDANCE APPEARS TO HAVE A GOOD HANDLE ON THIS...EXCEPT FOR
TONIGHT WHERE GUIDANCE ACROSS NORTH GEORGIA IS DROPPING LOWS INTO
THE LOW TO MID 60S. DO NOT SEE DRY AIR ADVECTING INTO THIS
AREA...AND WITH BEING IN THE TROPICAL AIR...WILL RAISE MIN TEMPS
TO WITHIN A DEGREE OF THIS MORNINGS LOWS.

LONG TERM /SATURDAY THROUGH WEDNESDAY/...
NO CHANGES FOR THE LONG TERM. THE H5 LOW WILL HOLD OVER THE GREAT
LAKES REGION PUTTING THE CWA IN A DRY NORTHWEST FLOW. THERE WILL BE
A WEAK SHORT WAVE THAT WILL ROTATE AROUND THE UPPER LOW AND ACROSS
THE EXTREME NORTH PART OF THE CWA. THIS COULD BRING A CHANCE OF
SHOWERS TO EXTREME NORTH GEORGIA SUNDAY INTO SUNDAY NIGHT...AND INTO
CENTRAL GEORGIA MONDAY. THE REST OF THE LONG TERM WILL BE DRY WITH
NEAR OR SLIGHTLY BELOW NORMAL TEMPS.

17
&&

.AVIATION...
06Z UPDATE...
COMPLICATED FORECAST...BUT OVERALL POOR AVIATION CONDITIONS EXPECTED
THROUGH TAF VALID PERIOD WITH LOW CIGS AND CONTINUED TSRA CHCS.
STALLED TROUGH/FRONT AND MOIST AIR MASS AND UPSTREAM ENERGY WILL
KEEP SHRA/TSRA GOING OFF/ON THROUGH DAYBREAK JUST EAST OF ATL-CSG.
THINK ATL AND CSG WILL ESCAPE THE MAJORITY OF THIS ACTIVITY...BUT IT
WILL BE CLOSE. MCN-AHN SHOULD SEE OFF/ON SHRA...ISOLD TSRA ALL NIGHT
AND INTO THE MORNING HOURS. INCREASING THREAT OF TSRA TOWARD CSG-ATL
AFT 16Z...WITH CONTINUED HIGHER THREAT MCN-AHN. WIDESPREAD MVFR CIGS
OVERNIGHT THROUGH 15Z...BUT LITTLE THREAT OF IFR. MVFR TO LOW END
VFR CIGS EXPECTED THROUGH REMAINDER OF TAF VALID PERIOD OUTSIDE
HEAVIER SHRA/TSRA. VSBYS MOSTLY VFR...EXCEPT 08Z-14Z MVFR BR...AND
MVFR IN HEAVIER SHRA/TSRA THROUGH TAF VALID PERIOD. WINDS CHAOTIC.
VRB03KT NOW...WILL TREND TOWARD ESE-SE 5-7KTS REMAINDER OF TAF VALID
PERIOD.

//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON CEILINGS.
MEDIUM ON VISIBILITY.
MEDIUM ON WIND DIR/SPD.
MEDIUM ON TSRA POTENTIAL.

19
&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          67  82  66  84 /  10  60  60  40
ATLANTA         69  83  68  81 /  10  60  50  40
BLAIRSVILLE     60  77  64  75 /  10  50  50  30
CARTERSVILLE    66  83  64  81 /  10  50  40  30
COLUMBUS        69  87  69  85 /  30  60  40  50
GAINESVILLE     65  81  67  80 /  10  60  50  40
MACON           70  86  67  85 /  40  60  50  50
ROME            65  84  65  81 /  10  50  40  30
PEACHTREE CITY  68  82  65  82 /  10  60  50  40
VIDALIA         70  86  70  85 /  40  60  40  60

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

19

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1054 PM EDT WED SEP 21 2011

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-221000-
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-
1054 PM EDT WED SEP 21 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH AND CENTRAL GEORGIA.

.DAY ONE...TONIGHT
ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS PORTIONS OF CENTRAL
GEORGIA UNTIL SHORTLY AFTER MIDNIGHT.

.SYNOPSIS...
A WEAK SURFACE BOUNDARY WILL CONTINUE TO MEANDER ACROSS CENTRAL
GEORGIA TONIGHT. A DEEP CLOSED UPPER LOW AND ASSOCIATED COLD FRONT
WILL APPROACH THE STATE FROM THE NORTHWEST LATE THURSDAY...THEN
MOVE THROUGH THE STATE FRIDAY.

.PRIMARY HAZARDS...
THE PRIMARY HAZARD FROM THUNDERSTORMS WILL BE OCCASIONAL CLOUD-
TO-GROUND LIGHTNING AND LOCALLY HEAVY RAIN. THE BEST CHANCE FOR
THUNDERSTORMS WILL BE SOUTH OF A LAGRANGE TO EATONTON TO
WASHINGTON LINE.

.DISCUSSION...
A WEAK BOUNDARY MEANDERING ACROSS CENTRAL GEORGIA WILL REMAIN THE
FOCUS FOR ISOLATED THUNDERSTORMS ACROSS THE AREA TONIGHT.
THUNDERSTORMS ARE EXPECTED TO REMAIN BELOW SEVERE LEVELS...BUT
WITH PRECIPITABLE WATER VALUES BETTER THAN AN INCH AND A
HALF...ANY STORM THAT DEVELOPS WILL BE CAPABLE OF PRODUCING
LOCALLY HEAVY RAIN.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY
SCATTERED THUNDERSTORMS ARE EXPECTED THURSDAY AND FRIDAY. NO
HAZARDOUS WEATHER IS ANTICIPATED SATURDAY THROUGH TUESDAY AT THIS
TIME.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT EXPECTED THROUGH TONIGHT.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
228 AM EDT THU SEP 22 2011

GAZ023-024-220730-
228 AM EDT THU SEP 22 2011

...SIGNIFICANT WEATHER ADVISORY FOR HEAVY RAIN IN BANKS AND HALL
COUNTIES UNTIL 330 AM EDT...

AT 223 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
THUNDERSTORM PRODUCING HEAVY RAIN OVER LULA...MOVING NORTHEAST AT 10
MPH. IN THE PAST HOUR...RADAR INDICATES ONE AND A HALF INCHES OF
RAIN HAS FALLEN OVER PORTIONS OF NORTHEAST HALL AND NORTHERN BANKS
COUNTIES. ADDITIONAL RAINFALL OF UP TO AN INCH CAN BE EXPECTED IN
THE NEXT HOUR.

RUNOFF FROM THESE STORMS WILL CAUSE MINOR FLOODING OF SMALL CREEKS
AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES ACROSS
BANKS AND HALL COUNTIES...INCLUDING AREAS AROUND LULA...CLERMONT...
PINEFIELD CROSSROADS AND HOLLINGSWORTH. ADDITIONALLY...COUNTRY ROADS
AND FARMLANDS ALONG THE BANKS OF CREEKS AND STREAMS ARE SUBJECT TO
MINOR FLOODING.

&&

LAT...LON 3444 8362 3450 8353 3448 8343 3446 8339
      3445 8339 3433 8358 3446 8380 3451 8377
      3451 8366
TIME...MOT...LOC 0625Z 206DEG 8KT 3445 8363