Severe Thunderstorm Warning 108, NWS Atlanta, GA

000 
WWUS52 KFFC 101146
SVSFFC

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
746 AM EDT FRI APR 10 2009

GAC055-115-233-295-101215-
/O.CON.KFFC.SV.W.0108.000000T0000Z-090410T1215Z/
POLK GA-FLOYD GA-CHATTOOGA GA-WALKER GA-
746 AM EDT FRI APR 10 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 AM EDT
FOR SOUTHERN WALKER...CHATTOOGA...FLOYD AND NORTHWESTERN POLK
COUNTIES...

AT 745 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING PENNY 
SIZED HAIL...AND DAMAGING WINDS UP TO 60 MPH. THESE STORMS WERE 
LOCATED ALONG A LINE EXTENDING FROM SUTTLES MILL TO COOSA TO 19 
MILES WEST OF CAVE SPRING...MOVING EAST AT 45 MPH.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
TIDINGS...SUBLIGNA...VILLANOW...ARMUCHEE...EVERETT SPRINGS...ROME AND
LINDALE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS.
REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING.

IF YOU SEE WIND DAMAGE...LARGE HAIL OR SIGNIFICANT FLOODING...WAIT
UNTIL AFTER THE STORM HAS PASSED...AND THEN CALL THE NATIONAL WEATHER
SERVICE TOLL FREE AT 1 8 6 6 7 6 3 4 4 6 6.

&&

LAT...LON 3469 8508 3432 8512 3416 8518 3403 8528
      3401 8541 3462 8554
TIME...MOT...LOC 1146Z 257DEG 43KT 3463 8519 3430 8535
          3404 8565

$$

AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
525 AM EDT FRI APR 10 2009

.SHORT TERM /TODAY THROUGH SUNDAY/...

MAIN CONCERN FOR THE SHORT TERM IS OBVIOUSLY SEVERE WEATHER THREAT
TODAY AND TONIGHT. CLOSED UPPER LOW OVER THE SOUTHERN PLAINS WILL
PROPAGATE EAST DURING THE DAY TODAY. SYSTEM WILL DAMPEN OUT WITH
TIME AND SURFACE LOW WILL GRADUALLY BEGIN TO FILL...BUT MOISTURE
RETURN AHEAD OF THE APPROACHING COLD FRONT WILL ALLOW INSTABILITY
TO INCREASE SIGNIFICANTLY DURING THE DAY. WARM FRONT WELL TO OUR
NORTH AND WE ARE SOLIDLY IN THE WARM SECTOR. GFS/NAM/ECMWF IN
GENERAL AGREEMENT ON TIMING WITH FIRST ROUND OF THUNDER MOVING
THROUGH THIS MORNING AS REMNANTS OF CONVECTIVE ACTIVITY CURRENTLY
IN NORTHEAST MISSISSIPPI AT AFD TIME. DRY SLOT BEHIND THIS INITIAL
ACTIVITY WILL ALLOW THE REGION TO DESTABILIZE FURTHER FOR THE
AFTERNOON...WHICH IS WHEN IT GETS INTERESTING. NAM SLIGHTLY SLOWER
THAN GFS WITH THIS SECOND ROUND AND SREF SEEMS TO LEAN TOWARD THE
NAM TIMING. ALL MODELS ARE LEANING HEAVILY TOWARD CONVECTIVE
ACTIVITY CONFINED TO NORTH GEORGIA...WITH HARDLY ANY IN CENTRAL
GEORGIA...BUT GIVEN THE MOISTURE RETURN AND APPROACHING FRONT AM
NOT WILLING TO PULL BACK ON CONVECTION IN CENTRAL GEORGIA JUST
YET.

AS FAR AS SEVERE CHANCES FOR THIS AFTERNOON...CAPES BETWEEN
1200-1800 J/KG...60+KT 0-6KM SHEAR... 200-300 M2/S2 0-1KM SRH...
50+ KT LLJ...AND 500MB TEMPS DECREASING RAPIDLY THROUGH THE
EVENING HOURS FROM -15C TO -20C IN NORTH GEORGIA. THIS CERTAINLY
DOES NOT COVER THE ENTIRE SPECTRUM OF VALUES...BUT END RESULT IS
NORTHERN HALF OF CWA IN MODERATE RISK FOR DAY1. WITH THE PROXIMITY
OF THE UPPER LOW...NO SURPRISE THAT WITH THE AMOUNT OF SHEAR IN
PLACE TO SUSTAIN LONG-LIVED SUPERCELLS WITH STRONG UPDRAFTS...
LARGE HAIL IS THE MAIN THREAT BUT WITH THE LLJ AND LOW LEVEL SHEAR
PARAMETERS DAMAGING WINDS AND ISOLATED TORNADOES ARE POSSIBLE.
ALONG THOSE LINES...FORECAST HODOGRAPHS FOR TODAY ARE VERY
IMPRESSIVE WITH A NICE CLOCKWISE CURVE. HAVE CONTINUED SEVERE
WORDING IN THE GRIDS BUT ADDED MENTION OF LARGE HAIL AND DAMAGING
WINDS TO LINE UP WITH THE MODERATE RISK AREA...THOUGH OF COURSE
THE LINE IS SUBJECT TO CHANGE.

WITH THE STRONG LLJ MOVING INTO THE AREA...WILL BE CONTINUING THE
WIND ADVISORY FOR THE MOUNTAINS THIS AFTERNOON AND EVENING.

UPPER LOW IS ABSORBED BY LONGWAVE TROUGH AND IS ONLY A SHORTWAVE
IMPULSE BY THE TIME THE SYSTEM MOVES OUT ON SATURDAY. HIGH
AMPLITUDE PATTERN IN PLACE ALLOWS A COOL HIGH PRESSURE TO SLIDE
EAST ACROSS SOUTHERN CANADA AND RIDGE DOWN THE EASTERN SLOPES OF
THE APPALACHIANS ON SUNDAY. CURRENT ADVERTISED HIGH TEMPS MAY BE
TOO WARM AS CLASSICAL CAD SETS UP. THIS WILL BE A FACTOR ON MONDAY
AS MEANWHILE ANOTHER SYSTEM GEARS UP OVER THE SOUTHERN PLAINS.

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...

ECMWF (00Z RUN) IS SLOWER THAN THE GFS WITH THIS NEXT SYSTEM...
WHICH IS PROBABLY A MORE REASONABLE SOLUTION GIVEN THE AMPLITUDE
OF THE RIDGE OVER THE EASTERN PART OF THE COUNTRY AND THE STRENGTH
OF THE CAD...THOUGH THE ECMWF DOES NOT USUALLY HANDLE CAD VERY
WELL. THE COLD DOME IN NORTHEAST GEORGIA WILL CERTAINLY HAVE A
STABILIZING INFLUENCE...BUT THEN AGAIN THE INHERENT HELICITY
ASSOCIATED WITH THE WEDGE FRONT...WHEREVER IT SETS UP...MAY
PROVIDE FOR AN INTERESTING SITUATION AS THE COLD FRONT APPROACHES
MONDAY MORNING. ECMWFS TIMING WOULD IMPLY INCREASED INSTABILITY
WITH THE SLIGHTLY SLOWER EASTWARD PROGRESSION...BUT BOTH MODELS
ARE INDICATING A LOT OF PRECIP IN THE NORTHERN GULF/FLORIDA
PANHANDLE...WHICH MAY SERVE TO CUT OFF THE DOWNSTREAM
PRECIPITATION (THAT IS...US). IN ANY EVENT...IT COULD BE A
POTENTIAL SEVERE WEATHER PRODUCER ALONG THE WEDGE FRONT...OR
SIMPLY A RAIN-MAKER WITH THE COOL OVERRUNNING PRECIPITATION.

GFS MOVES US INTO A NEAR-ZONAL FLOW PATTERN BY MIDWEEK AS THE
UPPER LOW SHIFTS NORTHEAST TOWARD THE GREAT LAKES...WHEREAS THE
ECMWF KEEPS THE UPPER LOW FURTHER SOUTH (OHIO VALLEY) WITH A
DEEPER TROUGH AND PRECIP LINGERING. SHOULD HAVE A LULL FOR A DAY
OR SO BEFORE THE NEXT LOW IN THE VERY PROGRESSIVE SERIES OF
SYSTEMS APPROACHES. CONFIDENCE EXTREMELY LOW THIS FAR OUT AS GFS
HAS SIGNIFICANT AMOUNT OF CONVECTIVE PRECIP (WITH A LOT OF
FEEDBACK) ACROSS THE DEEP SOUTH THURSDAY MORNING WHILE ECMWF IS
STILL IN THE SOUTHERN PLAINS. HAVE TAKEN A COMPROMISE ON THE
TIMING AND HAVE KEPT POPS TO AT MOST LOW CHANCE.

&&

.AVIATION...
RADAR SHOWS INITIAL PUNCH OF SHOWERS AND THUNDERSTORMS FASTLY
APPROACHING NW GA THIS MORNING. EXPECT THIS ACTIVITY TO WEAKEN AS IT
MOVES INTO THE WESTERN REACHES OF THE STATE. SHOULD SEE SOME SHOWER
ACTIVITY PUSH INTO THE ATLANTA AREA BY 14Z IF NOT SOONER SO MAY
START OUT WITH VCSH WITH THE 12Z ISSUANCE...BUT THE RADAR TRENDS
WILL HELP DECIDE THAT. OTHERWISE...EXPECT MVFR CIGS TO DEVELOP THIS
MORNING...MAINLY AROUND THE 2500 FT RANGE...AND MODELS SUGGEST THESE
CIGS WILL PREVAIL TODAY. HOWEVER...AFTER THIS INITIAL CONVECTIVE
SURGE THIS MORNING... AND THE AIRMASS RE-CHARGES AHEAD OF THE COLD
FRONT LATER THIS AFTERNOON...THE CIG MIGHT INCREASE INTO THE LOW VFR
RANGE BRIEFLY BY AFTERNOON...BUT INCLINED TO JUST HOLD ONTO MVFR FOR
NOW. STILL EXPECT THE GREATER TSTM THREAT AT ATL TO BE IN THE LATE
AFTERNOON-EARLY EVENING HOURS AS CURRENT TAFS SUGGEST. SHOWERS AND
TSTMS REMAIN POSSIBLE THRU THE EVENING UNTIL THE FRONT PUSHES ACROSS
THE ATLANTA AREA SOMETIME AROUND 06Z TONIGHT. MODELS SUGGEST LOW
ST/SC BEHIND THE FRONT MIGHT HOLD CIGS DOWN IN THE MVFR OR EVEN IFR
RANGE AFTER THE FROPA INTO THE MID SATURDAY MORNING HOURS.
OTHERWISE... A GUSTY SW WIND IS ON TAP TODAY AHEAD OF THE
APPROACHING COLD FRONT. /39

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          72  54  71  45  70 /  80  70   5   5   5
ATLANTA         71  52  68  49  71 /  90  50   0   5   5
BLAIRSVILLE     63  47  64  42  66 / 100  70  10   5   5
CARTERSVILLE    72  49  64  43  72 /  90  50  10  10   5
COLUMBUS        76  58  74  51  76 /  40  40   5   5   5
GAINESVILLE     69  52  67  46  67 /  90  60  10  10   5
MACON           77  55  75  50  76 /  40  50   5   5   5
ROME            72  50  67  46  73 / 100  50   5   5   5
PEACHTREE CITY  72  52  70  47  71 /  80  40   0   5   5
VIDALIA         77  62  77  53  76 /  20  40   5   5   5

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON TODAY TO MIDNIGHT EDT TONIGHT FOR THE
FOLLOWING ZONES: CHATTOOGA...DADE...DAWSON...FANNIN...GILMER...
LUMPKIN...MURRAY...PICKENS...TOWNS...UNION...WALKER...WHITE.

&&

TDP

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
500 AM EDT FRI APR 10 2009

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-110945-
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 FRI APR 10 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH AND CENTRAL GEORGIA.

.DAY ONE...TODAY AND TONIGHT
SCATTERED SEVERE STORMS ARE POSSIBLE THIS AFTERNOON AND EVENING.

.SYNOPSIS...
A STRONG SPRING STORM SYSTEM WILL MOVE ACROSS THE MID MISSISSIPPI
VALLEY REGION THIS AFTERNOON AND INTO THE LOWER OHIO VALLEY REGION
DURING THE EVENING HOURS. THIS SYSTEM WILL DRAG A STRONG COLD FRONT
ACROSS NORTH AND CENTRAL GEORGIA DURING EVENING AND EARLY MORNING
HOURS.

.PRIMARY HAZARDS...
THE PRIMARY HAZARDS WILL BE CLOUD TO GROUND LIGHTNING...LARGE HAIL
AND DAMAGING WINDS. ISOLATED TORNADOES WILL ALSO BE POSSIBLE.

.DISCUSSION...
INCREASING SOUTHERLY WINDS AHEAD OF AN APPROACHING STORM SYSTEM WILL
SERVE TO INCREASE MOISTURE AND INSTABILITIES OVER THE REGION THROUGH
THE AFTERNOON. AS THE UPPER LEVEL SYSTEM AND ASSOCIATED COLD FRONT
MOVE INTO THE TENNESSEE VALLEY THIS AFTERNOON...THE ATMOSPHERE WILL
RAPIDLY DESTABILIZE. CAPES WILL INCREASE TO 1200 TO 1800 AHEAD OF
THE COLD FRONT WITH LIFTED INDEX VALUES DECREASING TO AROUND -5.
ALTHOUGH SCATTERED SHOWERS AND THUNDERSTORMS WILL PUSH INTO THE
STATE DURING THE MORNING...THE GREATER THREAT OF STRONG STORMS
WILL OCCUR BETWEEN THE EARLY AFTERNOON AND LATE EVENING HOURS. AS
THE COLD FRONT APPROACHES NORTHWEST AND WEST CENTRAL GEORGIA BY
MID TO LATE AFTERNOON...STRONG TO SEVERE STORMS WILL LIKELY BECOME
MORE NUMEROUS...AND THEN SPREAD EASTWARD ACROSS THE REST OF NORTH
AND CENTRAL GEORGIA DURING THE EVENING HOURS. ALTHOUGH THE SEVERE
STORM THREAT IS ACROSS THE ENTIRE STATE...IT APPEARS THE GREATER
LARGE HAIL AND ISOLATED TORNADO THREAT WILL BE GENERALLY ALONG AND
NORTH OF A LA GRANGE TO MILLEDGEVILLE LINE WHERE THE MORE
FAVORABLE VERTICAL WIND SHEAR AND TEMPERATURE PROFILES WILL OCCUR.
THE SEVERE WEATHER THREAT WILL GREATLY DIMINISH SHORTLY AFTER
MIDNIGHT WITH THE PASSAGE OF THE COLD FRONT.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY
THERE IS A CHANCE OF THUNDERSTORMS MONDAY AND MONDAY NIGHT...AND
AGAIN THURSDAY THROUGH FRIDAY.

.SPOTTER INFORMATION STATEMENT...
SPOTTERS SHOULD BE PREPARED FOR ACTIVATION...ESPECIALLY THIS AFTERNOON
AND EVENING.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
558 AM EDT FRI APR 10 2009

GAZ001-002-101045-
558 AM EDT FRI APR 10 2009

...SIGNIFICANT WEATHER ALERT FOR FREQUENT LIGHTNING IN NORTHERN DADE
AND WALKER COUNTIES UNTIL 630 AM EDT...

AT 457 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS FROM 7 MILES NORTHWEST OF COLE CITY TO 15 MILES
SOUTHWEST OF STEPHENSVILLE...MOVING NORTHEAST AT 45 MPH.

THESE STORMS HAVE THE POTENTIAL TO PRODUCE PEA SIZED HAIL...FREQUENT
CLOUD TO GROUND LIGHTNING AND WIND GUSTS TO 35 MPH AS THEY MOVE
ACROSS DADE AND WALKER COUNTIES THROUGH 645 AM EDT. SOME LOCATIONS IN
THE PATH OF THESE STORMS INCLUDE COLE CITY...TRENTON...
STEPHENSVILLE...NEW ENGLAND...MORGANVILLE...CHATTANOOGA VALLEY...
LOOKOUT MOUNTAIN...HOOKER...WILDWOOD...FAIRVIEW AND ROSSVILLE. BRIEF
HEAVY DOWNPOURS WILL CAUSE PONDING OF WATER ON ROADWAYS.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
717 AM EDT FRI APR 10 2009

GAZ001>004-011-012-019-101200-
717 AM EDT FRI APR 10 2009

...SIGNIFICANT WEATHER ALERT FOR PEA SIZED HAIL AND 35 MPH WINDS IN
FLOYD...CHATTOOGA...GORDON...DADE...WALKER...WHITFIELD AND CATOOSA
COUNTIES UNTIL 800 AM EDT...

AT 616 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS FROM RISING FAWN TO 17 MILES WEST OF
CHATTOOGAVILLE...MOVING EAST AT 45 MPH.

THESE STORMS HAVE THE POTENTIAL TO PRODUCE PEA SIZED HAIL...FREQUENT
CLOUD TO GROUND LIGHTNING AND WIND GUSTS TO 35 MPH AS THEY MOVE
ACROSS FLOYD...CHATTOOGA...GORDON...DADE...WALKER...WHITFIELD AND
CATOOSA COUNTIES THROUGH 800 AM EDT. SOME LOCATIONS IN THE PATH OF
THESE STORMS INCLUDE RISING FAWN...CLOUDLAND CANYON STATE PARK...
CEDAR GROVE...MENLO...CLOUDLAND...COOPER HEIGHTS...CHATTOOGAVILLE...
LYERLY...BERRYTON...SUMMERVILLE...TRION...CENTER POST...LINWOOD...
BLUE SPRING AND CHICKAMAUGA. BRIEF HEAVY DOWNPOURS WILL CAUSE PONDING
OF WATER ON ROADWAYS.