Special Weather Statement, NWS Atlanta, GA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
332 PM EDT MON OCT 15 2012

.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
MODELS ALL AGREE ON A DRY FORECAST THROUGH WEDNESDAY. A WEAK SHORT
WAVE OVER NORTHERN MEXICO GETS ABSORBED INTO THE WESTERLIES AND
MOVES RAPIDLY INTO THE NORTHERN GULF COAST TUESDAY NIGHT INTO
WEDNESDAY. EXPECT MID AND HIGH LEVEL CLOUDS FROM THIS BUT NO PRECIP.

AFTER TUESDAY...TEMPS WILL START MODERATING. HAVING SAID
THAT...GUIDANCE TEMPS HAVE BEEN RUNNING 2 TO 6 DEGREES TOO COLD ON
OVERNIGHT LOWS OVER THE PAST 5 TO 10 DAYS...WILL THEREFORE CONTINUE
WITH PREVIOUS FORECAST MINS FOR TONIGHT AND WILL CONTINUE THIS TREND
FOR TUESDAY NIGHT. GUIDANCE HAS BEEN RUNNING 1 TO 3 DEGREES TOO WARM
IN MOST AREAS FOR DAYTIME MAX TEMPS AND WILL MAKE PROPER ADJUSTMENTS
TO MAX TEMPS BOTH TUESDAY AND WEDNESDAY.

17

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
OVERALL EXTENDED FORECAST LOOKS TO BE ON TRACK...WITH DRY AIR MASS
IN PLACE THROUGH EARLY THURSDAY...THEN NEXT COLD FRONTAL SYSTEM
PUSHING THROUGH. HAVE MADE MINOR ADJUSTMENTS TO POP...WX...AND
RELATED FORECAST ELEMENTS TO ACCOUNT FOR THE LATEST MODELS. MODELS
STILL IN DISAGREEMENT WITH PRECIP AMOUNTS AND OVERALL STRUCTURE OF
THE SYSTEM AS IT PUSHES THROUGH THE STATE...AND THEN DIVERGE MORE
SIGNIFICANTLY WITH THE PLACEMENT AND DEVELOPMENT OF A SECONDARY
SURFACE FEATURE. ECMWF STILL SIGNIFICANTLY WETTER THAN THE
GFS...KEEPING DECENT RAIN CHANCES ACROSS THE AREA THROUGH
FRIDAY...WELL BEYOND THE GFS WHICH USHERS HIGHER PRESSURE IN QUICKLY
BY EARLY FRIDAY.

HAVE ALSO MADE ADJUSTMENTS TO THE TEMPERATURES AND DEWPOINTS.
MODELS STILL SEEM RELATIVELY COOL THROUGH THE EXTENDED...SO HAVE
TWEAKED TO REFLECT LATEST MODEL TRENDS...FOCUSING ON THE SLIGHTLY
WARMER MODELS. OTHERWISE...NO MAJOR CHANGES WERE MADE AT THIS
TIME...AND THE PREVIOUS DISCUSSION FOLLOWS.

31

/ISSUED 437 AM EDT MON OCT 15 2012/
AS HIGH PRESSURE IN THE WAKE OF THE SHORT TERM COLD FRONT PASSAGE
ALLOWS FOR DRY CONDITIONS ACROSS THE FORECAST AREA THROUGH
WEDNESDAY...THE MAIN FORECAST CONCERN DURING THE LONG TERM CONTINUES
TO BE A SECOND CFP INFLUENCING THE AREA THURSDAY INTO FRIDAY. WITH
ITS INFLUENCE NOW STARTING TO MAKE IT INTO THE LATTER PART OF THE
SHORT TERM GUIDANCE SOLUTIONS...AND LESS VARIATION NOW ACROSS THE
GFS AND ECMWF RUNS...THERE IS MORE CONFIDENCE NOW ON AT LEAST THE
INITIAL IMPACTS OF THIS SYSTEM. ANY ASSOCIATED PRECIPITATION LOOKS
TO BEGIN IN NW GEORGIA BY NEAR 12Z THURSDAY SO WILL START CHANCE
POPS THEN.  THE ECMWF BRINGS THE UPPER JET A BIT FARTHER
SOUTH...ALONG WITH MORE UPPER LEVEL DIVERGENCE OVER THE
AREA...HOWEVER NOW HAS LESS OF A MOISTURE FIELD WITH THE INITIAL
INFLUENCE OF THE FRONT THAN THE GFS. IT ALSO IS LESS
PROGRESSIVE...STALLING THE FRONT ACROSS THE SOUTHEAST PORTION OF THE
AREA FRIDAY AFTERNOON AND NIGHT. DUE TO UNCERTAINTY...WILL GO WITH A
GENERAL BLEND IN POP COVERAGE THROUGH FRIDAY...ALTHOUGH INCLUDE BEST
CHANCE POPS IN THE THURSDAY TO THURSDAY NIGHT PERIOD. PROGGED MUCAPE
VALUES INDICATE THE GFS FAVORING ONLY SHOWERS...WHILE THE ECMWF IS A
BIT LESS STABLE AND WOULD SUPPORT AT LEAST AN ISOLATED THUNDER
CHANCE. WILL THEREFORE COMPROMISE WITH INCLUDING CHANCE SHOWERS AND
SLIGHT CHANCE THUNDERSTORMS FOR NOW.

THE ECMWF IS ALSO LESS PROGRESSIVE WITH THE UPPER TROUGH AND KEEPS
THE MAIN AXIS WEST OF THE AREA INTO SATURDAY AFTERNOON. SINCE THE
ECMWF OVERALL IS TRENDING MORE TOWARD THE GFS...WILL CONTINUE WITH A
DRY FORECAST FOR THE WEEKEND AND QUICKER BUILDING IN OF HIGH
PRESSURE. FOR TEMPS...MEX GUIDANCE HAS BEEN RATHER COOL SO STAYED
SLIGHTLY HIGHER THROUGH MAJORITY OF PERIOD.

BAKER

&&

.AVIATION...
18Z UPDATE...
SKIES IMPROVING THROUGH THE AFTERNOON WITH MOST AREAS SCT050. SKIES
WILL CLEAR TONIGHT WITH HIGH LEVEL CLOUDS MOVING IN LATE TUESDAY
MORNING. WINDS WILL BE NORTHWEST WITH GUSTS NEAR 20 TO 25KTS THIS
AFTERNOON. WINDS WILL GO NEAR CALM TONIGHT AND THEN LIGHT NORTH
TUESDAY.

//ATL CONFIDENCE...18Z UPDATE...
HIGH ON ALL ELEMENTS.

17

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          46  72  48  75 /   0   0   5   5
ATLANTA         51  72  54  76 /   0   0   5   5
BLAIRSVILLE     42  66  46  70 /   0   0   5   5
CARTERSVILLE    45  70  46  75 /   0   0   5   5
COLUMBUS        52  77  55  80 /   0   0   5   5
GAINESVILLE     47  70  51  73 /   0   0   5   5
MACON           47  78  47  79 /   0   0   5   5
ROME            44  72  48  76 /   0   0   5   5
PEACHTREE CITY  44  74  46  77 /   0   0   5   5
VIDALIA         54  77  54  76 /   0   0   5  10

&&

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

SHORT TERM...17
LONG TERM....31
AVIATION...17

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1208 PM EDT MON OCT 15 2012

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-161615-
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-
1208 PM EDT MON OCT 15 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH AND CENTRAL GEORGIA.

.DAY ONE...THIS AFTERNOON AND TONIGHT...
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SYNOPSIS...
A COLD FRONT WILL CONTINUE TO TRACK EASTWARD ACROSS NORTH AND
CENTRAL GEORGIA TODAY...WITH DRY HIGH PRESSURE BUILDING IN BEHIND IT.

.DISCUSSION...
SHOWER ACTIVITY WILL CONTINUE TO DIMINISH INTO THE AFTERNOON HOURS
AS THE FRONT PUSHES THROUGH THE AREA AND DRY AIR MOVES IN BEHIND
IT.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY...
ANOTHER COLD FRONT WILL IMPACT THE AREA THURSDAY INTO FRIDAY...
ALLOWING FOR A SLIGHT CHANCE OF THUNDERSTORMS.

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

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
419 PM EDT MON OCT 15 2012

GAZ111-112-152045-
419 PM EDT MON OCT 15 2012

...SIGNIFICANT WEATHER ADVISORY FOR FREQUENT LIGHTNING IN WHEELER AND
MONTGOMERY COUNTIES UNTIL 445 PM EDT...

AT 417 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM OVER JORDAN...MOVING EAST AT 25 MPH.

LIGHTNING DETECTION SYSTEMS INDICATE NUMEROUS CLOUD-TO-GROUND
LIGHTNING STRIKES ACROSS WHEELER AND MONTGOMERY COUNTIES...INCLUDING
AREAS AROUND SPRING HILL...GLENWOOD...MOUNT VERNON...JORDAN...
UVALDA...ALSTON AND CHARLOTTEVILLE. RESIDENTS IN THIS AREA SHOULD
STAY INDOORS. ELECTRICAL APPLIANCES AND TELEPHONES SHOULD NOT BE USED
UNLESS IN AN EMERGENCY.

&&

LAT...LON 3193 8267 3201 8273 3201 8275 3202 8278
      3221 8266 3212 8246 3196 8248 3194 8249
      3195 8252 3195 8256 3192 8263
TIME...MOT...LOC 2020Z 289DEG 22KT 3203 8266

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
437 PM EDT MON OCT 15 2012

GAZ113-152100-
437 PM EDT MON OCT 15 2012

...SIGNIFICANT WEATHER ADVISORY FOR FREQUENT LIGHTNING IN TOOMBS
COUNTY UNTIL 500 PM EDT...

AT 435 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM OVER CENTER...MOVING EAST AT 25 MPH.

LIGHTNING DETECTION SYSTEMS INDICATE NUMEROUS CLOUD-TO-GROUND
LIGHTNING STRIKES ACROSS TOOMBS COUNTY...INCLUDING AREAS AROUND ROCK
SPRINGS...VIDALIA...CENTER...CEDAR CROSSING...SOUTH THOMPSON...TOOMBS
CENTRAL...SANTA CLAUS...PONDEROSA...NEW BRANCH...JOHNSON CORNER AND
OHOOPEE. RESIDENTS IN THIS AREA SHOULD STAY INDOORS. ELECTRICAL
APPLIANCES AND TELEPHONES SHOULD NOT BE USED UNLESS IN AN EMERGENCY.

&&

LAT...LON 3208 8220 3202 8220 3197 8221 3204 8247
      3220 8245 3222 8244 3218 8218 3215 8218
TIME...MOT...LOC 2037Z 287DEG 21KT 3212 8240