Severe Thunderstorm Warning 181, NWS Atlanta, GA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
840 PM EDT FRI MAY 9 2008

.UPDATE...
SOME MINOR CHANGES MADE TO THE ONGOING FORECAST. FIRST...LIMITED
SLIGHT CHANCE POPS FOR THIS EVENING TO THE NORTHERN TIER OF
COUNTIES. SHORT WAVE TRACKING ALMOST DUE EAST ACROSS TN GENERATING
ISOLD +TSRA. SOUTHWARD EXTENT OF THIS SHOULD ONLY MAKE IT TO THE
GA/TN BORDER OR PERHAPS ONE TIER OF COUNTIES INTO N GA. DO NOT FEEL
THAT ANY SHRA/TSRA ACTIVITY WILL MAKE INTO THE NORTHERN SUBURBS OF
ATL. WILL HOLD ONTO A SLIGHT CHANCE SHRA/TSRA FOR THE NE COUNTIES
AFT 06Z AS SHORT WAVE TRACKS FURTHER EAST. SECOND...EXTREME
INSTABILITY INDICATED ACROSS CENTRAL GA AFT 18Z SAT WITH LIS -7 AND
CAPES NEAR 4000 J/KG. WEAK STATIONARY FRONT DRAPED ACROSS
CENTRAL/SOUTHERN PORTIONS OF N GA COULD BE THE FOCUS FOR AT LEAST
ISOLD SVR TSRA DURING THE AFTERNOON. GIVEN PROGGED INSTABILITY AND
MODEST SHEAR...HAVE ADDED SEVERE WORDING TO TSRA FOR SAT AFTERNOON
AND EVENING ALL EXCEPT NE GA...WHICH AREA APPEARS TO HAVE A PSEUDO
WEDGE IN PLACE. EXTREME INSTABILITY CONTINUES SUN NIGHT ACROSS ALL
EXCEPT THE NE PART OF THE STATE...WITH INCREASING SHEAR AND DYNAMICS
AS STRONG UPPER LOW AND COLD FRONT APPROACH FROM THE WEST. 18Z RUN
OF GFS WOULD SUGGEST MAIN POTENTIAL FOR SVR IN FFC CWA MAY BE IN THE
00Z SUN - 12Z SUN TIME PERIOD...PERHAPS BEGINNING IN THE 18Z SAT-00Z
SUN TIME FRAME FOR THE SOUTHERN PARTS OF THE CWA ALONG STATIONARY
FRONT...EXPECTED TO LIFT NORTHWARD SAT EVENING INTO N GA. AFT 12Z
SUN...MAIN THREAT FOR SVR MAY BE FURTHER EAST IN THE
CAROLINAS...WITH 18Z RUN SHOWING ONLY LIMITED POTENTIAL FOR SVR IN
FFC CWA...EXCEPT PERHAPS FAR EASTERN AREAS...AFT 12Z.

DID NOT MAKE ANY CHANGES TO TEMPS FOR TONIGHT. DEWPOINTS ARE
SLIGHTLY LOWER THAN LAST NIGHT AT THIS TIME AND CLOUD COVER LESS.
SLIGHTLY COOLER PROGGED MORNING LOWS MAY BE REALIZED...SO DO NOT
MAKE ANY CHANGES AT THIS TIME.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
MODELS IN CLOSE AGREEMENT THROUGH THE SHORT TERM WITH MINOR
DIFFERENCES ON TIMING AND STRENGTH. FOR TONIGHT...MODELS NOT REAL
EXCITED ABOUT THE PROSPECTS FOR PRECIP WITH SLIGHT CHANCE PROGGED
ACROSS THE NORTH. THIS SEEMS REASONABLE AS A SHORT WAVE MOVING
ACROSS THE MID MISSISSIPPI AND OHIO VALLEYS WILL CONTINUE ITS
EASTWARD MOVEMENT. THERE WILL BE A TRAILING VORT LOBE THAT WILL MOVE
ACROSS THE TENNESSEE VALLEY THIS EVENING. AFTERWARD DRIER AIR MOVES
INTO THE REGION ENDING THE PRECIP. ON SATURDAY A WEAK SHORT WAVE
RIDGE TRIES TO BUILD OVER THE STATE WHILE A SERIES OF WEAK SHORT
WAVES MOVES ACROSS THE REGION. AT THE SAME TIME THE SURFACE BOUNDARY
SETTLES INTO CENTRAL GA. LAPSE RATES UP TO H8 EXCEED 7 DEGREES OVER
MOST AREAS AND EVEN H8 TO H7 LAPSE RATES ARE RUNNING AROUND 7
DEGREES. SURFACE BASED CAPES AT 18Z SAT EXCEED 2000 ACROSS CENTRAL
GA WITH LIS OF -4 TO -6. THE LIMITING FACTOR IS MOISTURE. FEEL WITH
THE SURFACE BOUNDARY ACROSS CENTRAL GA AND WEAK SHORT WAVES
PROVIDING SOME LIFT...THERE SHOULD BE SCATTERED THUNDERSTORMS ACROSS
CENTRAL AND PARTS OF NORTH GA SATURDAY AFTERNOON...AND ANY THAT DO
DEVELOP COULD BE SEVERE BASED ON STABILITY INDICES. ALTHOUGH MAV IS
INDICATING NIL POPS...MET IS GIVING 30S POPS ACROSS CENTRAL GA AND
WILL FOLLOW CLOSE TO MET POPS.

SATURDAY NIGHT A BACKDOOR COLD FRONT MOVES INTO NORTH GA BRINGING A
MORE STABLE BOUNDARY LAYER TO NORTHEAST GA. AT THE SAME TIME THE
SURFACE BOUNDARY ACROSS CENTRAL GEORGIA LIFTS TO THE BACKDOOR COLD
FRONT AND STOPS. THE MAIN SHORTWAVE WILL ALSO BE MOVING INTO THE
SOUTHEAST BRINGING MOISTURE. WILL BE INCREASING POPS SATURDAY NIGHT.

SUNDAY WILL BE TRICKY WITH THE STABLE EAST TO NORTHEAST FLOW ACROSS
NORTHEAST GA AND A WEST TO SOUTHWEST FLOW ELSEWHERE. MAIN AREA OF
MOISTURE EXITS THE CWA BY 18Z SUNDAY...HOWEVER GFS IS INDICATING
SOME LIFT ALONG THE COLD FRONT. FEEL THERE WILL BE A BREAK IN THE
PRECIP WITH THE SATURDAY NIGHT RAIN ENDING SUNDAY MORNING...THEN
SQUALL LINE ALONG THE FRONT MOVING ACROSS THE CWA SUNDAY AFTERNOON.
AS FOR SEVERE WEATHER...APPEARS THE BEST INSTABILITY WILL BE SOUTH
OF I-20 AFT 18Z WITH NOT MUCH BEFORE HAND. THERE ARE TWO LIMITING
FACTORS. FIRST IS THE LIMITED MOISTURE. AS STATED MOST OF THE
MOISTURE EXITS THE STATE WITH SOME MOISTURE CONVERGENCE ALONG THE
FRONT. SECOND...ARE THE LAPSE RATES. DEFINITELY NOT AS IMPRESSIVE AS
THEY ARE ON SATURDAY AFTERNOON. HOWEVER WILL CONTINUE TO MENTION
SOME POSSIBLY SEVERE SUNDAY AFTERNOON...EXCEPT FOR THE NORTHEAST
WHERE THE COOL DOME WILL PROTECT THEM. BY SUNDAY EVENING THE FRONT
IS OUT OF THE CWA AND DRIER AIR SPREADS ACROSS THE CWA.

.LONG TERM /MONDAY THROUGH FRIDAY/...
H5 RIDGE BUILDS OVER THE STATE MONDAY AND TUESDAY BRINGING STABLE
AIR TO THE REGION. FOR THE REST OF THE LONG TERM...SIGNIFICANT
MODEL DIFFERENCES EXIST BETWEEN GFS AND THE ECMWF AND CONFIDENCE
IN THE FORECAST IS VERY LOW. MODELS ARE STRUGGLING WITH HOW STRONG
THE UPPER LEVEL TROUGH/LOW WILL BE OVER THE EASTERN CONUS. WILL
NOT VENTURE TO FAR FROM GUIDANCE NEXT WEEK UNTIL THE MODELS CAN
CONVERGE ON A SOLUTION.

&&

.AVIATION...
FEW CU DISSIPATING THIS EVENING. HOWEVER...SHORT WAVE NOW VICINITY
OF W TN SHOULD PROGRESS EASTWARD TONIGHT...BRINGING CEILINGS 3 TO
5THSD FT AND A FEW SHOWERS TO N GA 05Z-09Z. OTHERWISE...PATCHY
MID/HIGH CLOUDS OVERNIGHT. VISIBILITY UNRESTRICTED EXCEPT SOME AREAS
OF 3 TO 5SM IN FOG AFTER 07Z. WINDS WEST TO SOUTHWEST 5 TO 10KT
OVERNIGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          63  86  61  70  51 /  10  10  70  70  10
ATLANTA         64  83  66  74  51 /   5  10  70  60   5
BLAIRSVILLE     58  76  53  65  45 /  20  10  80  80  10
CARTERSVILLE    61  82  61  70  49 /  20  10  80  60  10
COLUMBUS        68  87  70  81  57 /   5  30  50  60   5
GAINESVILLE     63  80  60  67  51 /  20  10  80  80  10
MACON           65  89  68  81  54 /   0  30  40  60  10
ROME            61  83  63  74  49 /  20  10  80  50  10
PEACHTREE CITY  61  86  64  77  51 /   5  20  70  60   5
VIDALIA         69  91  69  84  56 /   5  30  20  60  20

&&

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

17/41/19

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
958 PM EDT FRI MAY 9 2008

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-101215-
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-
958 PM EDT FRI MAY 9 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH AND CENTRAL GEORGIA.

.DAY ONE...TONIGHT
THERE IS A SLIGHT CHANCE OF THUNDERSTORMS TONIGHT ACROSS NORTH
GEORGIA...MAINLY NORTH OF A ROME TO GAINESVILLE TO DANIELSVILLE
LINE.

.SYNOPSIS...
A COLD FRONT HAD STALLED JUST NORTH OF GEORGIA...AND WILL REMAIN
IN THE VICINITY UNTIL A STRENGTHENING LOW PRESSURE SYSTEM MOVING
THROUGH THE OHIO VALLEY SENDS A POWERFUL COLD FRONT ACROSS GEORGIA
ON SUNDAY.

.PRIMARY HAZARDS...
THE PRIMARY HAZARDS WILL BE STRONG WINDS AND OCCASIONAL LIGHTNING.

.DISCUSSION...
AN UPPER LEVEL DISTURBANCE WAS CROSSING THE TENNESSEE VALLEY
REGION THIS EVENING. THIS FEATURE HAD TRIGGERED ISOLATED
THUNDERSTORMS OVER TENNESSEE. INSTABILITY INDICIES WERE MARGINAL
ACROSS NORTH GEORGIA...AND ANY THUNDERSTORMS THAT DEVELOP IN THAT
AREA SHOULD REMAIN BELOW SEVERE LIMITS. THE MOST FAVORED AREA FOR
ANY CONVECTION IS NORTH OF A ROME TO GAINESVILLE TO DANIELSVILLE
LINE FOR THE REMAINDER OF THE NIGHT.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY
THE AIRMASS WILL BECOME INCREASINGLY UNSTABLE ON SATURDAY AND
EVEN MORE SO SATURDAY NIGHT INTO EARLY SUNDAY AS A FRONTAL
BOUNDARY REMAINS DRAPED ACROSS THE LOCAL AREA. THIS WILL ALLOW FOR
A GREATER LIKELIHOOD OF ISOLATED SEVERE THUNDERSTORMS SATURDAY
AFTERNOON AND EVENING...POSSIBLY INTO THE EARLY MORNING HOURS OF
SUNDAY.

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

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
236 AM EDT SAT MAY 10 2008

GAZ009-100700-
236 AM EDT SAT MAY 10 2008

...SIGNIFICANT WEATHER ALERT FOR FREQUENT LIGHTNING IN TOWNS COUNTY
UNTIL 300 AM EDT...

AT 233 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 5 MILES NORTH OF HIAWASSEE...MOVING SOUTHEAST AT
34 MPH.

THIS STORM HAS THE POTENTIAL TO PRODUCE PEA SIZED HAIL...FREQUENT
CLOUD TO GROUND LIGHTNING AND WIND GUSTS TO 35 MPH AS IT MOVES ACROSS
TOWNS COUNTY THROUGH 300 AM EDT. SOME LOCATIONS IN THE PATH OF THIS
STORM INCLUDE ALEXANDERS MILL...YOUNG HARRIS...HIAWASSEE...PRESLEY
AND TATE CITY. BRIEF HEAVY DOWNPOURS WILL CAUSE PONDING OF WATER ON
ROADWAYS.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
325 AM EDT SAT MAY 10 2008

GAZ020-021-100800-
325 AM EDT SAT MAY 10 2008

...SIGNIFICANT WEATHER ALERT FOR PEA SIZED HAIL AND 35 MPH WINDS IN
CHEROKEE AND BARTOW COUNTIES UNTIL 400 AM EDT...

AT 322 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM OVER CASSVILLE...MOVING SOUTHEAST AT 30 MPH.

WIND GUSTS OF 35 MPH ARE LIKELY AS THIS STORM MOVES ACROSS CHEROKEE
AND BARTOW COUNTIES THROUGH 400 AM EDT. SOME LOCATIONS IN THE PATH
OF THE STORM INCLUDE CASSVILLE...KINGSTON...ADAIRSVILLE...PINE LOG...
WHITE...WALESKA...CANTON...CHEROKEE...BUFFINGTON...BALL
GROUND...LEBANON...HOLLY SPRINGS AND FREE HOME.