Special Weather Statement, NWS Atlanta, GA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
138 PM EDT SUN JUL 29 2012

.PREV DISCUSSION...

UPDATE...
/ISSUED 1052 AM EDT SUN JUL 29 2012/
MSAS DEW POINT AND PRESSURE ANALYSIS INDICATES THE FRONT IS
SITUATED ACROSS CENTRAL GEORGIA...BETWEEN ATL AND THE CSG TO MCN
AREA. FORECAST THINKING IS STILL ON TRACK WITH BEST PRECIP CHANCES
ALONG AND SOUTH OF THE FRONT SO NO CHANGES TO THE AFTERNOON POPS.
FORECAST IS OVERALL IN LINE WITH THE 11Z HRRR RUN SHOWING ISOLATED
DEVELOPMENT ACROSS NORTH GEORGIA WITH HIGHER COVERAGE ACROSS THE
SOUTHERN THIRD OF THE FORECAST AREA.

ONLY TWEAKS TO THE FORECAST ARE BASED ON CURRENT TEMP...DEW POINT
AND RADAR TRENDS. CUT DOWN ON POPS ACROSS CENTRAL GEORGIA FOR THE
REST OF THE MORNING AS THE AREA OF SHOWERS THAT PERSISTED THROUGH
MUCH OF THE MORNING HAS DISSIPATED.

11

SHORT TERM /TODAY THROUGH MONDAY/...
/ISSUED 350 AM EDT SUN JUL 29 2012/
LATEST SURFACE ANALYSIS SHOWS SURFACE FRONT HAS MADE ITS WAY INTO
THE ATLANTA METRO AREA WITH LOW END SCATTERED COVERAGE OF SHOWERS
AND VERY ISOLATED THUNDERSTORMS MARKING ITS LEADING EDGE. HAVE
MADE SOME MINOR INITIAL GRID MODIFICATIONS TO TAKE POPS THROUGH
12Z. OTHERWISE...AREA IS UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES
WITH INITIALIZED UPPER LEVELS SHOWING CONTINUED TROUGH DEVELOPMENT
IN THE TENNESSEE VALLEY AND INTO THE LOCAL AREA.

FOR THE REMAINDER OF TODAY...ANTICIPATE MAIN DEVELOPMENT TO BE
ALONG THE MAIN FRONT AND ENHANCED POPS EXPECTED WITH AFTERNOON
HEATING. THIS WILL GENERALLY OCCUR OVER SOUTHERN SECTIONS OF THE
FORECAST AREA AND WILL FOCUS HIGHEST GRIDDED POPS THERE. CONTINUE
TO WATCH AREA ALONG THE FRONT OF ENHANCED DOWNDRAFT CAPE WITH
CLOSE TO 1000 J/KG ACCOUNTING FOR NUMEROUS OUTFLOWS SEEN ON RADAR
DESPITE SHALLOW CORES. ANTICIPATING THIS AREA TO SHIFT SOUTH WITH
SOME THREAT OF AN ISOLATED SEVERE WIND GUST IN STRONGEST ACTIVITY
THIS AFTERNOON.

EXPECTING SOME DRY AIR TO MIX DOWN THIS AFTERNOON BUT WITH TEMPS
LIKELY SLIGHTLY ABOVE GUIDANCE AGAIN...WILL SEE SOME ISOLATED HEAT
INDICES ABOVE 105. LIKE YESTERDAY...NOT EXPECTING WIDESPREAD
ENOUGH CONDITIONS TO WARRANT ADVISORY.

FOR MONDAY...STILL A GOOD DEAL OF DRY AIR IN PLACE AT THE MID
LEVELS TO INHIBIT CONVECTION INITIALLY. HOWEVER...A LATE ARRIVING
SHORTWAVE LOOKS TO PROVIDE TO FOCUS FOR ENHANCED ACTIVITY AND WILL
GO ABOVE GUIDANCE FOR POPS WITH LOW END CHANCE.

DEESE

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
/ISSUED 350 AM EDT SUN JUL 29 2012/
DISSIPATING STATIONARY FRONT OR SURFACE TROUGH ACROSS THE AREA TO
START THE LONG TERM WITH AN UPPER TROUGH ALONG THE EASTERN SEABOARD.
MODELS INDICATING THE POTENTIAL FOR SHORT WAVES IN THE NW FLOW ALOFT
TO AFFECT THE AREA MONDAY NIGHT AND TUESDAY ALLOWING FOR THE CHANCE
OF SHOWERS AND THUNDERSTORMS. THIS POTENTIAL FOR SHORT WAVES TO
AFFECT THE FORECAST AREA LOOKS TO CONTINUE WEDNESDAY AND THURSDAY.
ON FRIDAY THE UPPER RIDGE BEGINS TO BUILD AND LOOKS TO CONTINUE OVER
THE AREA THE REST OF THE LONG TERM. THIS SHOULD DIMINISH SOME THE
OVERALL POTENTIAL FOR SHOWERS AND THUNDERSTORMS WITH A HIGHLY
DIURNAL NATURE TO ANY CONVECTION.

HIGH TEMPERATURES SHOULD MODERATE SOME FOR THE FIRST PART OF THE
LONG TERM WITH HIGHS IN THE LOWER HALF OF THE 90S ON THE HIGH SIDE
AND THEN WARM TO THE UPPER HALF OF THE 90S TO NEAR 100 AT WEEKS END.

BDL

&&

.AVIATION...
18Z UPDATE...
FRONT REMAINS JUST SOUTH OF THE ATL TO AHN AREA AND BEST CHANCE OF
CONVECTION WILL REMAIN ALONG AND SOUTH OF THIS FRONT. THIS MEANS
THE BEST CHANCE OF TSRA WILL BE AT MCN AND CSG THIS AFTERNOON.
THERE IS A SLIGHT CHANCE AT THE REMAINDER OF THE SITES...BUT NOT
HIGH ENOUGH TO MENTION IN THE TAF. HAVE STARTED TO SEE SOME GUSTS
ACROSS ATL SITES AND THESE WILL LAST INTO AT LEAST THE FIRST HALF
OF THE AFTERNOON.

//ATL CONFIDENCE...18Z UPDATE...
HIGH CONFIDENCE ON WIND...CIGS AND VSBY. MEDIUM CONFIDENCE ON
TSRA NOT OCCURRING AT ATL.

11

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          97  70  96  72 /  20  20  30  20
ATLANTA         96  73  94  75 /  20  20  30  20
BLAIRSVILLE     89  63  89  66 /  20  20  20  40
CARTERSVILLE    93  64  95  70 /  20  20  30  40
COLUMBUS        97  74  97  75 /  40  30  30  20
GAINESVILLE     93  71  92  72 /  20  20  30  30
MACON           97  72  96  73 /  40  30  30  20
ROME            94  64  95  70 /  20  20  30  40
PEACHTREE CITY  94  67  95  70 /  20  20  30  20
VIDALIA         93  75  96  75 /  40  40  40  20

&&

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

UPDATE...11
SHORT TERM...DEESE
LONG TERM....BDL
AVIATION...11

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
500 AM EDT SUN JUL 29 2012

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-301000-
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-
500 AM EDT SUN JUL 29 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH AND CENTRAL GEORGIA.

.DAY ONE...TODAY AND TONIGHT...
ISOLATED SEVERE THUNDERSTORMS POSSIBLE ACROSS CENTRAL GEORGIA THIS
AFTERNOON AND EVENING.

.SYNOPSIS...
A COLD FRONT WILL BECOME STATIONARY ACROSS CENTRAL GEORGIA THROUGH
TONIGHT.

.PRIMARY HAZARDS...
THE PRIMARY HAZARDS FROM THUNDERSTORMS WILL BE DAMAGING WINDS AND
LIGHTNING. THE MOSTLY LIKELY AREA FOR SEVERE THUNDERSTORMS WILL BE
ACROSS CENTRAL GEORGIA FROM NEAR COLUMBUS TO NEAR AUGUSTA AND
SOUTH...THIS AFTERNOON AND EVENING.

.DISCUSSION...
SOUTH OF THE FRONT CAPES WILL INCREASE 1500 TO 3000 THIS AFTERNOON.
THIS INSTABILITY COMBINED WITH GOOD LOW LEVEL MOISTURE AND
CONVERGENCE NEAR THE FRONT WILL GIVE THE POSSIBILITY FOR ISOLATED
SEVERE THUNDERSTORMS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY...
THERE WILL BE A CHANCE OF THUNDERSTORMS EACH DAY.

.SPOTTER INFORMATION STATEMENT...
SPOTTERS ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1152 AM EDT SUN JUL 29 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0622 PM     TSTM WND DMG     2 E GARDEN VALLEY       32.44N 84.08W
07/28/2012                   MACON              GA   911 CALL CENTER

            MIDDLE FLINT 911 RELAYED A REPORT OF A DOWNED TREE IN THE
            GA HWY 127 AREA OF MACON COUNTY. TIME ESTIMATED OFF
            RADAR.

&&

RGARCIA

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
141 PM EDT SUN JUL 29 2012

GAZ098-112-291815-
141 PM EDT SUN JUL 29 2012

...SIGNIFICANT WEATHER ADVISORY FOR FREQUENT LIGHTNING AND WIND
GUSTS TO 40 MPH IN TREUTLEN AND MONTGOMERY COUNTIES UNTIL 215 PM
EDT...

AT 139 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM OVER LOTHAIR...MOVING SOUTHEAST AT 10 MPH.VERY
HEAVY RAINFALL AND WIND GUSTS TO 40 MPH CAN ALSO BE EXPECTED.

LIGHTNING DETECTION SYSTEMS INDICATE FREQUENT CLOUD-TO-GROUND
LIGHTNING STRIKES ACROSS TREUTLEN AND MONTGOMERY COUNTIES...INCLUDING
AREAS AROUND BARNHILL...LOTHAIR...SOPERTON AND TARRYTOWN. RESIDENTS
IN THIS AREA SHOULD STAY INDOORS. ELECTRICAL APPLIANCES AND CORDED
TELEPHONES SHOULD NOT BE USED UNLESS IN AN EMERGENCY.

&&

LAT...LON 3225 8257 3233 8272 3240 8268 3237 8252
TIME...MOT...LOC 1740Z 293DEG 7KT 3235 8265

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
223 PM EDT SUN JUL 29 2012

GAZ085-291845-
223 PM EDT SUN JUL 29 2012

...SIGNIFICANT WEATHER ADVISORY FOR FREQUENT LIGHTNING IN EASTERN
JOHNSON COUNTY UNTIL 245 PM EDT...

AT 220 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR NEW HOME OR 8 MILES EAST OF WRIGHTSVILLE...
MOVING EAST AT 15 MPH. VERY HEAVY RAIN...HAIL TO THE SIZE OF DIMES
AND WIND GUSTS TO 40 MPH CAN BE EXPECTED.

LIGHTNING DETECTION SYSTEMS INDICATE FREQUENT CLOUD-TO-GROUND
LIGHTNING STRIKES ACROSS JOHNSON COUNTY...INCLUDING AREAS AROUND NEW
HOME AND KITE. RESIDENTS IN THIS AREA SHOULD STAY INDOORS. ELECTRICAL
APPLIANCES AND TELEPHONES SHOULD NOT BE USED UNLESS IN AN EMERGENCY.

&&

LAT...LON 3272 8245 3269 8250 3266 8249 3272 8264
      3280 8261 3281 8258 3280 8249 3276 8244
TIME...MOT...LOC 1822Z 285DEG 12KT 3275 8258

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
251 PM EDT SUN JUL 29 2012

GAZ097-291915-
251 PM EDT SUN JUL 29 2012

...SIGNIFICANT WEATHER ADVISORY FOR FREQUENT LIGHTNING...PEA SIZED
HAIL AND 40 MPH WINDS IN LAURENS COUNTY UNTIL 315 PM EDT...

AT 247 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM CENTERED NEAR DEXTER...MOVING EAST AT 10 MPH.

THIS STORM HAS THE POTENTIAL TO PRODUCE PEA SIZED HAIL...FREQUENT
CLOUD TO GROUND LIGHTNING AND WIND GUSTS TO 40 MPH AS IT MOVES ACROSS
LAURENS COUNTY THROUGH 315 PM EDT. SOME LOCATIONS IN THE PATH OF THIS
STORM INCLUDE DEXTER...CADWELL AND RENTZ.

&&

LAT...LON 3243 8293 3229 8298 3238 8311 3246 8308
TIME...MOT...LOC 1851Z 286DEG 10KT 3240 8306

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
259 PM EDT SUN JUL 29 2012

GAZ086-291930-
259 PM EDT SUN JUL 29 2012

...SIGNIFICANT WEATHER ADVISORY FOR FREQUENT LIGHTNING...PEA SIZED
HAIL AND 40 MPH WINDS IN EMANUEL COUNTY UNTIL 330 PM EDT...

AT 257 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM OVER DELLWOOD...MOVING SOUTHEAST AT 15 MPH.

THIS STORM HAS THE POTENTIAL TO PRODUCE PEA SIZED HAIL...FREQUENT
CLOUD TO GROUND LIGHTNING AND WIND GUSTS TO 40 MPH AS IT MOVES ACROSS
EMANUEL COUNTY THROUGH 330 PM EDT. SOME LOCATIONS IN THE PATH OF THIS
STORM INCLUDE DELLWOOD...MODOC AND SWAINSBORO. MOVE INDOORS UNTIL
THE STORM PASSES AND YOU CAN NO LONGER HEAR THUNDER. MANY LIGHTNING
DEATHS OCCUR AFTER THE RAIN HAS ENDED.

&&

LAT...LON 3248 8235 3261 8251 3264 8250 3263 8249
      3265 8247 3266 8249 3271 8246 3272 8245
      3266 8226
TIME...MOT...LOC 1858Z 297DEG 12KT 3264 8244