River Flood Warning 275, NWS Atlanta, GA

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1236 AM EST THU DEC 31 2015

.UPDATE...
/ISSUED AT 628 PM EST WED DEC 30 2015/
HAVE TWEAKED POPS A BIT ACCORDING TO THE LATEST RADAR TRENDS. MCV
OVER EASTERN AL WILL MOVE NORTHEAST INTO CENTRAL GA THIS EVENING.
THIS FEATURE SHOULD ENHANCE RAINFALL ALONG ITS TRACK. AXIS OF
HEAVIER RAIN HAS FINALLY PUSHED SOUTH OF THE SOUTHERN METRO...BUT
MAY SHIFT SLIGHTLY NORTHWARD AGAIN AS THE MCV MOVES ALONG THE
STALLED FRONT. NO CHANGES TO THE FLOOD WATCH AT THIS TIME.

&&

.PREV DISCUSSION... /ISSUED 243 PM EST WED DEC 30 2015/

SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...

..HEAVY RAIN/FLOODING CONTINUES ACROSS PORTIONS OF CENTRAL AND
NORTH GA...

LATEST WATER VAPOR SATL IMAGERY CONTINUES TO SHOW PLUME OF SUB-
TROPICAL MOISTURE STREAMING ACROSS THE SOUTHEAST REGION. PERIODS OF
RAIN WILL CONTINUE THROUGH TONIGHT AS A SERIES OF UPR LVL WAVES
CONTINUE TO TRAIN ACROSS SFC-H85 BOUNDARY THAT IS SET UP FROM
SOUTHWEST ALABAMA TO NORTHEAST GEORGIA AT THIS TIME. 30-40KT LOW LVL
FLOW PARALLEL TO BOUNDARY IS MAINTAINING THE RAIN AND OCNL TSTMS...
ESPECIALLY ALONG THE LEADING EDGE OF THE PRECIP SHIELD WHERE AXIS OF
MARGINAL INSTABILITY EXISTS.

THROUGH THURSDAY NIGHT...SLOWLY...THE ABOVE MENTIONED LOW LVL
FRONTAL BOUNDARY AND ASSOCIATED MOISTURE PLUME WILL DRIFT SOUTH AND
EAST. AS THIS OCCURS...THE HEAVIEST RAIN AXIS WILL MOVE ACROSS THE
SOUTHERN COUNTIES OF CENTRAL GA WHERE FLOOD CONCERNS WILL QUICKLY
DEVELOP FROM NEW RAINFALL AND UPSTREAM HEAVY RAIN/RUNOFF. EXPECT
ADDITIONAL RAINFALL TONIGHT THROUGH THURSDAY NIGHT TO RANGE FROM 1
TO 2.5 INCHES ALONG/SOUTH OF A COLUMBUS TO WASHINGTON LINE WITH
LESSER AMOUNTS NORTH. LITTLE IF ANY ADDITIONAL RAIN ACROSS THE
EXTREME NORTHWEST GA AREA HAS LED TO DECISION TO PULL 4 COUNTIES
/DADE...WALKER...CHATTOOGA...CATOOSA/ FROM THE FLOOD WATCH.

THE 12Z NAM IS HINTING AT ONE FINAL PUSH OF HEAVY RAIN ACROSS THE
SOUTHERN TIER THURSDAY NIGHT INTO EARLY FRIDAY. DID NOT DISCOUNT
THIS POSSIBILITY GIVEN PERSISTENT PATTERN. WENT AHEAD AND ADJUSTED
WPC QPF A BIT FARTHER NORTH AND RAISED AMOUNTS SLIGHTLY AS WELL TO
ACCOUNT FOR THIS POTENTIAL SOLUTION. OTHERWISE...COOLER AND
RELATIVELY DRIER AIR WILL FINALLY BEGIN TO FILTER ACROSS THE AREA
FROM THE NORTHWEST WITH HIGH TEMPS STRUGGLING TO GET OUT OF THE 50S
FROM ALONG NORTH/WEST OF AN I-20/I-85 LINE TOMORROW (THURSDAY). EVEN
COOLER CONDITIONS EXPECTED ON FRIDAY WITH DAYTIME TEMPS ACTUALLY
EXPECTED TO BE SEVERAL DEGREES BELOW NORMAL FOR THE FIRST TIME IN
NEARLY TWO WEEKS!

DJN.83

LONG TERM /FRIDAY THROUGH WEDNESDAY/...
NO MAJOR CHANGES MADE TO THE EXTENDED FORECAST. RAIN CHANCES WILL
DIMINISH FROM NORTH TO SOUTH FRIDAY AS FRONT PUSHES SOUTH AND EAST
OF THE FORECAST AREA THROUGH SAT MORNING. BEST CHANCES WILL
REMAIN OVER CENTRAL GEORGIA WITH SOME DRYING NOTED ACROSS NORTH
GEORGIA BY LATE AFTERNOON. THE UPPER LEVEL SHORT WAVE FINALLY
PUSHES EAST OF THE APPALACHIANS ON SATURDAY WITH DRY CONDITIONS
EXPECTED THROUGH THE EXTENDED PERIODS...AS UPPER TROUGH DEEPENING
ALONG THE EAST COAST INDUCES WEAK RIDGING ALOFT THROUGH MID WEEK.
MODELS DIVERGE ON HOW QUICKLY MOISTURE IS ABLE TO RETURN...BUT FOR
NOW WILL KEEP FORECAST DRY AND CONTINUE TO MONITOR. TEMPERATURES
WILL RETURN TO NEAR NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE
50S AND LOWS IN THE MID TO UPPER 30S.

01

&&

.AVIATION...
06Z UPDATE...
AXIS OF HEAVIER PRECIP HAS PUSHED SOUTH OF ATL WITH IFR/LIFR CIGS
NOW EXPECTED TO SETTLE IN BY 09Z THIS MORNING. MOS GUIDANCES AND
OVERALL MODEL TRENDS SHOW THE GREATER PRECIP CHANCES SOUTH OF ATL
TODAY... WITH GRADUAL CIG IMPROVEMENT EXPECTED INTO THE AFTERNOON.
WILL STAY CLOSE TO THIS TREND FOR NOW. WINDS WILL START OUT 3-4KTS
AND DANCE FROM SSE TO SSW BEFORE BECOMING WNW BY 09-10Z... THEN NW
BY 14-16Z IF NOT SOONER. NW WINDS INCREASE TO AROUND 8-10KTS BY LATE
MORNING/EARLY AFTERNOON. MODEL GUIDANCES SHOW MOSTLY HIGH CLOUDS
TONIGHT AS DRIER AIR SPREADS IN FROM THE NW... BUT COULD SEE SOME
LOW CIGS DEVELOP LATE WITH SUCH WET GROUNDS.

//ATL CONFIDENCE...06Z UPDATE...
LOW TO MED CONFIDENCE ON CIGS.

/39

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          55  63  46  56 /  80  50  30  10
ATLANTA         52  59  44  51 /  70  40  30  10
BLAIRSVILLE     47  58  37  47 /  50  20  10  10
CARTERSVILLE    47  57  38  48 /  50  30  20  10
COLUMBUS        58  61  48  52 /  90  70  60  30
GAINESVILLE     52  62  44  52 /  60  30  20  10
MACON           60  63  47  55 /  90  80  60  30
ROME            46  57  37  48 /  40  20  10  10
PEACHTREE CITY  52  58  41  51 /  70  50  30  20
VIDALIA         67  72  54  61 /  50  70  80  60

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH FRIDAY EVENING FOR THE FOLLOWING ZONES:
BALDWIN...BANKS...BARROW...BARTOW...BIBB...BLECKLEY...BUTTS...
CARROLL...CHATTAHOOCHEE...CHEROKEE...CLARKE...CLAYTON...COBB...
COWETA...CRAWFORD...CRISP...DAWSON...DEKALB...DOOLY...DOUGLAS...
FANNIN...FAYETTE...FLOYD...FORSYTH...GILMER...GLASCOCK...
GORDON...GREENE...GWINNETT...HALL...HANCOCK...HARALSON...
HARRIS...HEARD...HENRY...HOUSTON...JACKSON...JASPER...
JEFFERSON...JONES...LAMAR...LUMPKIN...MACON...MADISON...MARION...
MERIWETHER...MONROE...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...TOWNS...TROUP...TWIGGS...UNION...UPSON...
WALTON...WARREN...WASHINGTON...WEBSTER...WHITE...WHITFIELD...
WILKES...WILKINSON.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
245 PM EST WED DEC 30 2015

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-311100-
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-
245 PM EST WED DEC 30 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH AND
CENTRAL GEORGIA.

.DAY ONE...TONIGHT...

PERIODS OF MODERATE TO HEAVY RAIN WITH ISOLATED THUNDERSTORMS WILL
AFFECT MUCH OF NORTH AND CENTRAL GEORGIA...ESPECIALLY SOUTH OF I-85.
EXPECT SIGNIFICANT RIVER...STREAM AND LOWLAND FLOODING ALONG WITH
LOCALIZED FLASH FLOODING. ADDITIONAL RAINFALL TONIGHT WILL BE
BETWEEN 1/2 AND 1 INCH WITH LOCALLY HIGHER AMOUNTS UP TO 2 INCHES
POSSIBLE OVER AREAS FROM COLUMBUS TO MACON TO WASHINGTON.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...

RAIN WILL CONTINUE INTO FRIDAY FOR AREAS ESPECIALLY SOUTH OF A
COLUMBUS TO MACON TO SANDERSVILLE LINE. RIVER FLOODING WILL CONTINUE
WITH ISOLATED FLASH FLOODING POSSIBLE IN POOR DRAINAGE AND OTHER
FLOOD PRONE AREAS. ISOLATED THUNDERSTORMS ARE ALSO POSSIBLE IN THIS
AREA BUT THE THREAT FOR SEVERE WEATHER IS LOW AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

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

DJN