Flash Flood and Hail in Georgia, May 16, 2003

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
555 PM EDT THU 15 MAY 2003

...UPDATED TO INCLUDE AVATION DISCUSSION...

MODELS SOMEWHAT CONSISTENT IN BRINGING A SERIES OF SHORT WAVES
THROUGH THE FLOW...AND WITH THE AVAILABLE MOISTURE THAT IS BEING
FORECASTED...WILL KEEP A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE
FORECAST. THE RIDGE OF HIGH PRESSURE OVER THE NORTHEAST KEEPS THE
AREA OF LOW PRESSURE OVER THE SOUTHWEST SPINNING OVER THE EAST TX
AND LA REGION PUSHING THESE IMPULSES EASTWARD.  THE CONCERN WILL BE
WHETHER ENOUGH MOISTURE WILL AVAILABLE TO FUEL THE PCPN CHANCES INTO
NEXT WEEK.

.PRELIMINARY POINT TEMPS/POPS...

KATL 61 82 64 76 / 30 30 30 30
KAHN 60 83 63 76 / 30 30 30 30
KGVL 59 82 61 72 / 30 30 30 40
KRMG 58 83 61 78 / 20 30 30 40
KCSG 63 85 68 85 / 30 30 30 30
KMCN 62 85 66 83 / 30 30 30 30

.ATL WATCHES/WARNINGS/ADVISORIES...
GA...NONE.

..AVIATION DISCUSSION...
OVERALL TREND IS FOR DRYING OUT IN THE SHORT TERM. NEGATIVE VORTICITY
ADVECTION ASSOCIATED WITH WEAK RIDGING UPSTREAM SHOULD KEEP THIS
TREND OVERNIGHT. THE RESULT WILL LIKELY BE NO CIGS...OTHER THAN
THE SLIGHT POSSIBILITY OF SOME DEBRIS OFF CONVECTION IN THE
FAR NORTH AND OVER SOUTHERN GEORGIA. EXPECTING DECOUPLING
OVERNIGHT...BUT THIS MAY BE DELAYED TIL LATER IN THE NIGHT
DUE TO PRESSURE GRADIENT THAT EVENTUALLY RELAXES. LIGHT SOUTHWEST
LOW LEVEL WINDS WILL BRING IN SLIGHTLY HIGHER DEWPOINTS. THIS
SETS US UP FOR SOME PREDAWN FOG WITH VISIBILITIES GENERALLY
3 OR 4 MILES. THE FIRST CONVECTIVE CURRENTS OF THE MORNING
AFTER SUNRISE COULD CAUSE SCATTERED TO BROKEN CLOUDS WITH
BASES AROUND 1 THOUSAND FEET. THE BOUNDARY LAYER SHOULD QUICKLY
DEEPEN AND THE TREND WOULD BE FOR SCATTERED CUMULUS IN A VERY
SHORT PERIOD (MAYBE AN HOUR OR TWO).

15

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-152045-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1110 AM EDT THU MAY 15 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH AND CENTRAL GEORGIA.

.DAY ONE...TODAY.

ISOLATED STRONG THUNDERSTORMS POSSIBLE ACROSS NORTH GEORGIA.

.SYNOPSIS...
A WEAK WARM FRONT OVER SOUTHERN GEORGIA WILL DRIFT NORTH TODAY.
ONE UPPER LEVEL DISTURBANCE EXITS GEORGIA TODAY...AND ANOTHER WILL
MOVE OVER THE STATE FRIDAY.

.PRIMARY HAZARD...
THE PRIMARY HAZARD FROM THUNDERSTORMS TODAY WILL BE FREQUENT
CLOUD-TO-GROUND LIGHTNING AND BRIEF HEAVY RAIN. ISOLATED STORMS WILL
BECOME STRONG AND PRODUCE HAIL UP TO 1/2 INCH IN DIAMETER AND WIND
GUSTS TO 40 MPH. THE MOST LIKELY AREA FOR STRONGER STORMS WILL BE
NORTHWEST OF A LINE FROM CEDARTOWN TO ELLIJAY BETWEEN 2 PM AND 9 PM.

.DISCUSSION...
THE WARM FRONTAL BOUNDARY WILL CONTINUE TO SERVE AS A FOCUSING
MECHANISM FOR THUNDERSTORM DEVELOPMENT TODAY. AS IT DRIFTS VERY
SLOWLY NORTH...THE BEST AREA FOR THUNDERSTORM DEVELOPMENT WILL
MOVE NORTH ALSO. AS THE UPPER DISTURBANCE PASSES EAST OF THE AREA
DURING THE AFTERNOON...THUNDERSTORMS WILL BECOME LESS NUMEROUS.
MARGINAL INSTABILITY WITH LIFTED INDICES OF -2 TO -4 AND CAPES OF
500 SOUTH TO AROUND 1500 NORTH WILL SUPPORT ISOLATED STRONG
THUNDERSTORMS.

.FOR SPOTTERS...
ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT PERSONNEL IS
NOT LIKELY TODAY...HOWEVER STORM SPOTTERS AND EMERGENCY MANAGEMENT
PERSONNEL SHOULD MONITOR WEATHER CONDITIONS AND LATER UPDATES ON
THIS WEATHER SITUATION.

.DAY TWO THROUGH DAY SEVEN...FRIDAY THROUGH WEDNESDAY.

AN UNSETTLED WEATHER PATTERN WILL CONTINUE ACROSS THE AREA INTO NEXT
WEEK. THERE WILL BE A CONTINUING CHANCE OF THUNDERSTORMS JUST ABOUT
EVERY DAY. AT THIS TIME...SATURDAY APPEARS TO BRING THE BEST THREAT
OF SEVERE THUNDERSTORMS.

GAZ031>033-160545-

SIGNIFICANT WEATHER ALERT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1248 AM EDT FRI MAY 16 2003

...SIGNIFICANT WEATHER ALERT FOR VERY HEAVY RAIN AND SIGNIFICANT
CLOUD-TO-GROUND LIGHTNING IN COBB...NORTH FULTON...AND PAULDING
COUNTIES UNTIL 145 PM EDT...

THE NATIONAL WEATHER SERVICE DOPPLER RADAR DETECTED AN BAND OF
PERSISTENT THUNDERSTORMS..DRIFTING SLOWLY SOUTHEAST...EXTENDING FROM
JUST WEST OF DALLAS IN PAULDING COUNTY...TO MARIETTA IN COBB
COUNTY...TO BUCKHEAD IN FULTON COUNTY. THESE THUNDERSTORMS ARE
PRODUCING VERY HEAVY RAINFALL ON THE ORDER OF 1 TO 1.5 INCHES PER
HOUR ALONG WITH CONSIDERABLE CLOUD-TO-GROUND LIGHTNING.

THIS RAINFALL MAY CAUSE FLOODING OF LOW-LYING AND POOR DRAINAGE
AREAS...ESPECIALLY IN URBAN AREAS. IF DRIVING...BE ESPECIALLY ALERT
TO AREAS OF HIGH WATER AND DO NOT DRIVE YOUR VEHICLE INTO AREAS
WHERE WATER COVERS THE ROAD. THE WATER MAY BE TOO DEEP FOR YOU TO
PROCEED SAFELY.

RAB