Special Weather Statement, NWS Atlanta, GA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
212 PM EDT SAT JUL 7 2012

.SHORT TERM /TONIGHT THROUGH MONDAY/...
AN UPPER LEVEL HIGH PRESSURE RIDGE CENTERED OVER THE MID WEST
WILL CONTINUE TO BROADEN AND DAMPEN OUT THROUGH THE REMAINDER OF
THE WEEKEND AND INTO NEXT WEEK. A WEAK SURFACE TROUGH REMAINS
POSITIONED ACROSS GEORGIA...BUT EXTRA MOISTURE ACROSS WEST AND
NORTH GEORGIA WAS BETTER ASSOCIATED WITH LOW PRESSURE FEATURE
DEVELOPING OVER THE DEEP SOUTH. AS A RESULT...BEST DIURNAL
CONVECTION WILL OCCUR IN THESE REGIONS...AND HAVE GENERALLY GONE
WITH CHANCE POPS IN THESE AREAS...TAPERING THEM OFF OVERNIGHT
TONIGHT. SIMILAR SITUATION IN STORE FOR SUNDAY WITH A SURFACE
TROUGH REDEFINING ITSELF ACROSS NORTH GEORGIA...PROVIDING A FOCUS
FOR DEVELOPMENT. GOOD SURFACE HEATING AND MOISTURE WILL SUPPORT
CAPE IN THE 1500-2500 J/KG RANGE...AND DAMAGING WINDS AND SMALL
HAIL WILL ONCE AGAIN BE THE PRIMARY CONCERNS.

BY MONDAY...THE UPPER LEVEL RIDGE WILL NOT BE AS DISCERNIBLE...AS
THE UPPER LEVEL DISTURBANCE DEVELOPS OVER THE SOUTHERN MISSISSIPPI
RIVER. THIS UPPER LEVEL FEATURE...COMBINED WITH SURFACE BOUNDARY
WILL KEEP PRECIP CHANCES CONCENTRATED OVER THE SOUTHERN
MISSISSIPPI AND TN VALLEYS...WITH BEST CHANCES OF RAIN ACROSS FAR
NORTH GEORGIA. DUE TO PLACEMENT UNCERTAINTIES BETWEEN THE
MODELS...HAVE ONLY GONE WITH GOOD CHANCE POPS ACROSS NORTH GEORGIA
THROUGH MONDAY. OVERALL...MODELS INDICATING THIS SYSTEM BEING THE
BEGINNING OF A WETTER WEEK FOR THE STATE.

AS FOR TEMPERATURES...STILL EXPECTING HIGHS IN THE 90S THROUGH THE
SHORT TERM...WITH WARMER TEMPERATURES OVER THE EASTERN PORTION OF
THE CWA...AS INCREASED MOISTURE AND AMPLE CLOUD COVER PROTECT THE
WESTERN HALF. OVERNIGHT LOWS WILL BE IN THE 70S...WITH UPPER 60S
IN SOME OF THE OUTLYING AREAS AND GA MOUNTAINS. OVERALL...TOOK A
BLEND OF THE MAV/MET.

31

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
NO CHANGES PLANNED. PREVIOUS LONG TERM DISCUSSION FOLLOWS...

/ISSUED 459 AM EDT SAT JUL 7 2012/
BY MONDAY A PERSISTENT BROAD LONGWAVE TROUGH SETS UP OVER THE
EASTERN U.S. THE ECMWF/GFS ARE CONSISTENT KEEPING THE SOUTHEAST
UNDER THE INFLUENCE OF THE TROUGH. AT THE SFC...THE WEAK SURFACE
BOUNDARY WAVERS ACROSS THE SOUTHEAST THROUGH THE EXTENDED PERIODS.
THE COMBINATION OF WEAK UPPER LEVEL IMPULSES...THE WEAK SURFACE
BOUNDARY...ENOUGH MOISTURE TO TAP INTO...AND PLENTY OF INSTABILITY
WILL BRING NEAR NORMAL TEMPERATURES AND CONTINUED CHANCE OF
CONVECTION ACROSS THE AREA.

ATWELL/17

&&

.AVIATION...
18Z UPDATE...
ISOLATED TO SCATTERED CONVECTION EXPECTED ACROSS NORTH AND CENTRAL
GA THIS AFTERNOON AND EVENING...WITH HIGHEST CHANCES ACROSS
WESTERN GA AND THE NE GA MTNS. ALTHOUGH THERE IS A POSSIBILITY FOR
THUNDER AT ALL TAF SITES...HAVE ONLY INCLUDED TEMPO TS AT
CSG...WHERE UNCERTAINTY IS NOT AS HIGH. SW WINDS WILL PERSIST
THROUGH THE AFTERNOON AT 5-8KTS...AND WILL GRADUALLY SWITCH AROUND
TO THE WEST BY TONIGHT. LIGHT TO NEAR CALM WINDS OVERNIGHT WILL
BECOME SW AT 5-8KTS AGAIN TOMORROW. UNCERTAINTY TOO HIGH TO ADD TS
IN TAF FOR AFTER 18Z TOMORROW AT ATL. VFR CIGS EXPECTED THROUGH
THE PERIOD...EXCEPT POSSIBLE HIGH END MVFR IN CONVECTION.

//ATL CONFIDENCE...18Z UPDATE...
HIGH CONFIDENCE ON ALL ELEMENTS. MODERATE TO HIGH CONFIDENCE
CONVECTION WILL NOT IMPACT ATL AIRPORT THIS AFTERNOON.

31

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          73  98  72  96 /  20  20  20  40
ATLANTA         73  93  73  91 /  20  20  20  40
BLAIRSVILLE     69  89  68  88 /  30  40  40  50
CARTERSVILLE    69  94  69  92 /  20  30  30  40
COLUMBUS        72  94  73  93 /  30  20  20  30
GAINESVILLE     73  94  72  92 /  20  30  30  40
MACON           72  96  72  95 /  20  20  20  20
ROME            70  96  71  93 /  20  40  30  50
PEACHTREE CITY  69  93  70  92 /  20  20  20  30
VIDALIA         75  97  75  96 /  10  20  20  20

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
608 AM EDT SAT JUL 7 2012

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-081015-
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-
608 AM EDT SAT JUL 7 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH AND CENTRAL GEORGIA.

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

.SYNOPSIS...
WEAK UPPER LEVEL IMPULSES WILL CONTINUE TO MOVE ACROSS THE
SOUTHEAST U.S. IN THE FLOW OF AN UPPER LEVEL RIDGE OVER THE
CENTRAL PLAINS.

.PRIMARY HAZARDS...
THE PRIMARY HAZARDS FROM THE ISOLATED SEVERE THUNDERSTORMS WILL
BE QUARTER SIZED HAIL...DAMAGING WINDS...LIGHTNING...AND BRIEF
HEAVY RAIN. THE BEST TIME FOR THUNDERSTORM DEVELOPMENT WILL MID
AFTERNOON THROUGH EVENING.

.DISCUSSION...
UPPER LEVEL IMPULSES MOVING ACROSS THE AREA...AS WELL AS
BOUNDARIES LEFT OVER FROM CONVECTION LAST NIGHT AND THIS MORNING
WILL COMBINE WITH GOOD INSTABILITY AND PLENTY OF MOISTURE TO
PRODUCE SCATTERED THUNDERSTORMS...WITH ISOLATED SEVERE STORMS
POSSIBLE. MOST STORMS WILL BE CAPABLE OF PRODUCING STRONG TO
SEVERE WIND GUSTS DUE TO THE PRESENCE OF ENHANCED DOWNDRAFT
PARAMETERS. IN ADDITION...LARGE HAIL WILL BE POSSIBLE IN THE
STRONGER STORMS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...
GENERALLY SCATTERED COVERAGE IS EXPECTED FOR MOST AREAS AGAIN ON
SUNDAY AS DIURNALLY DRIVEN CONVECTION WILL PREVAIL. THE STORMS
WILL BECOMING FOCUSED IN THE VICINITY OF A PERSISTENT SURFACE
BOUNDARY MONDAY THROUGH FRIDAY.

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

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1242 PM EDT SAT JUL 07 2012

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

0709 PM     TSTM WND DMG     4 E STOCKBRIDGE         33.54N 84.16W
07/06/2012                   HENRY              GA   EMERGENCY MNGR

            THE HENRY COUNTY EMERGENCY MANAGER AND LOCAL MEDIA
            REPORTED 40-50 TREES DOWN EAST OF STOCKBRIDGE. TIME IS
            BASED ON RADAR.

&&

20

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
529 PM EDT SAT JUL 7 2012

GAZ034-035-047-072200-
529 PM EDT SAT JUL 7 2012

...SIGNIFICANT WEATHER ADVISORY FOR 45 MPH WINDS IN WALTON...BARROW
AND GWINNETT COUNTIES UNTIL 600 PM EDT...

AT 524 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM OVER BOLD SPRINGS...MOVING NORTHWEST AT 5 MPH.

THIS STORM HAS THE POTENTIAL TO PRODUCE PEA SIZED HAIL...FREQUENT
CLOUD TO GROUND LIGHTNING AND WIND GUSTS TO 45 MPH AS IT MOVES ACROSS
WALTON...BARROW AND GWINNETT COUNTIES THROUGH 600 PM EDT. SOME
LOCATIONS IN THE PATH OF THIS STORM INCLUDE WINDSOR...
NICHOLASVILLE...BOLD SPRINGS...FORT YARGO STATE PARK...RUSSELL...
BETHLEHEM...CARL...HARBIN...AUBURN...HOG MOUNTAIN...LAWRENCEVILLE...
GRAYSON AND DACULA. HEAVY DOWNPOURS WILL CAUSE PONDING OF WATER ON
ROADWAYS.

THESE WIND GUSTS MAY PRODUCE MINOR DAMAGE TO TREE LIMBS AND BLOW
LIGHT...UNSECURED OBJECTS AROUND.

&&

LAT...LON 3389 8406 3409 8396 3398 8368 3381 8377
TIME...MOT...LOC 2129Z 112DEG 6KT 3393 8383

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
558 PM EDT SAT JUL 7 2012

GAZ033-034-045-072230-
558 PM EDT SAT JUL 7 2012

...SIGNIFICANT WEATHER ADVISORY FOR 45 MPH WINDS IN DEKALB...GWINNETT
AND FULTON COUNTIES UNTIL 630 PM EDT...

AT 551 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR SHOWED STRONG
THUNDERSTORMS FROM AROUND MECHANICSVILLE TO GRAYSON...MOVING
NORTHWEST AT 10 MPH.

THESE STORMS HAVE THE POTENTIAL TO PRODUCE PEA SIZED HAIL...FREQUENT
CLOUD TO GROUND LIGHTNING AND WIND GUSTS TO 45 MPH AS THEY MOVE
ACROSS GWINNETT AND NORTHERN DEKALB AND FULTON COUNTIES THROUGH 630
PM EDT. SOME LOCATIONS IN THE PATH OF THESE STORMS INCLUDE PLEASANT
HILL...HARBIN...SNELLVILLE...NORCROSS...MECHANICSVILLE...LILBURN...
GRAYSON...TUCKER.. .DORAVILLE...CHAMBLEE...MOUNTAIN PARK...DACULA...
DUNWOODY...LAWRENCEVILLE AND BERKELEY LAKE. HEAVY DOWNPOURS WILL
CAUSE PONDING OF WATER ON ROADWAYS.

THESE WIND GUSTS MAY PRODUCE MINOR DAMAGE TO TREE LIMBS AND BLOW
LIGHT...UNSECURED OBJECTS AROUND.

&&

LAT...LON 3412 8426 3410 8425 3405 8412 3405 8410
      3407 8412 3410 8410 3406 8399 3401 8388
      3393 8381 3387 8387 3380 8401 3388 8435
      3407 8439
TIME...MOT...LOC 2156Z 123DEG 9KT 3398 8426 3393 8393