Areal Flood Warning 20, NWS Atlanta, GA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1052 AM EDT SAT JUL 13 2013

.UPDATE...
RAIN SO FAR HAS BEEN CONFINED TO EASTERN GA. THINK THE HRRR IS
DECENT IS TERMS OF WHAT IT IS SHOWING FOR TODAY. SHOULD SEE
DEVELOPMENT OF SCATTERED SHOWERS ACROSS THE REMAINDER OF THE CWA
AROUND NOONTIME. CURRENT POP TRENDS LOOK REASONABLE. MAIN CONCERN
WITH THE FORECAST FOR TODAY IS POTENTIAL FOR LOCALIZED FLOODING.
ALTHOUGH OVERALL RAINFALL AMOUNTS ARE EXPECTED TO BE ON THE LOWER
SIDE...LOCALIZED HIGHER AMOUNTS ARE POSSIBLE WITH TRAINING.
ALREADY HAVE LOCALIZED FLOODING ACROSS PARTS OF EASTERN GA...AND
WILL BE INVESTIGATING THIS MORE FOR THE POTENTIAL NEED OF A FLASH
FLOOD WATCH ACROSS EASTERN GA.

11

&&

.PREV DISCUSSION...

SHORT TERM /TODAY THROUGH SUNDAY/...
/ISSUED 422 AM EDT SAT JUL 13 2013/
NAM/GFS IN DECENT AGREEMENT WITH MOVING LOW PRESSURE ALOFT OVER THE
OH/TN VALLEY WEST ACROSS THE MS VALLEY THROUGH EARLY SUNDAY WITH
UPPER HIGH PRESSURE BUILDING OVER THE NE STATES LATE TODAY THROUGH
SUNDAY. THIS ALLOWS DEEPER MOISTURE TO MOVE BACK OVER THE AREA FROM
THE SE TODAY AND TONIGHT AND CONTINUE OVER THE AREA FOR SUNDAY.
THE POTENTIAL FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
WILL INCREASE ACROSS THE AREA ESPECIALLY FROM LATE MORNING
ON...INCREASING HIGHEST OVER THE SE 2/3RDS OF THE FORECAST AREA.
THINK CONVECTION WILL BE SLOW TO WIND DOWN OVERNIGHT WITH SOME
CHANCE FOR SHOWERS THROUGHOUT THE LATE NIGHT. NUMEROUS SHOWERS AND
THUNDERSTORMS CAN BE EXPECTED FOR SUNDAY...TENDING TO MAXIMIZE
DURING THE AFTERNOON...AS ABUNDANT MOISTURE AND DECENT INSTABILITY
WILL BE IN PLACE.

MOS POPS FOR N AND PARTS OF CENTRAL GA SEEM TOO LOW FOR TODAY AND
HAVE STAYED CLOSER TO CURRENT FORECAST.

FORECAST HIGH TEMPERATURES RUNNING ABOUT 5-8 DEGREES BELOW NORMAL
TODAY AND SUNDAY. FORECAST LOW TEMPERATURES RUNNING CLOSE TO NORMAL.

OVERALL CONFIDENCE IS MEDIUM TO HIGH.

BDL

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
/ISSUED 422 AM EDT SAT JUL 13 2013/
UPPER LOW MOVING WEST AT THE START OF THE PERIOD WITH STRONG UPPER
RIDGE OVER THE NORTHEAST. TROPICAL MOISTURE STILL BEING DRAWN MOVING
ACROSS THE CWA AT DURING THE FIRST OF THE WEEK. A DEEP EASTERLY
FLOW PATTERN WILL KEEP ATLANTIC MOISTURE OVER THE CWA THROUGH MUCH
OF THE PERIOD. THE FLOW BECOMES MORE SOUTHWESTERLY BY THURSDAY
INTO FRIDAY AS THE UPPER RIDGE WEAKENS A BIT A SHIFTS SOUTHWARD.
IN GENERAL...HAVE BASICALLY KEPT CHANCE POPS EACH DAY WITH SLIGHT
CHANCE OVERNIGHT THROUGH THE PERIOD. A DIURNAL PATTERN SHOULD
BECOME MORE PROMINENT THROUGH THE WEEK...WITH AFTERNOON
TEMPERATURES BECOMING A BIT WARMER.

41

HYDROLOGY...
/ISSUED 422 AM EDT SAT JUL 13 2013/
NO CONFIDENCE FOR A FLASH FLOOD WATCH AT THIS TIME. HOWEVER MOST
THUNDERSTORMS WILL BE ABLE TO PRODUCE HEAVY RAIN AND IF THEY ARE
SLOW MOVERS OR TRAIN OVER THE SAME AREA...LOCALIZED FLASH FLOODING
WILL BE POSSIBLE. AVERAGE RAINFALL AMOUNTS THE NEXT COUPLE DAYS WILL
BE 1 INCH OR LESS.

AVIATION...
12Z UPDATE...
/ISSUED 722 AM EDT SAT JUL 13 2013/
IFR-MVFR CEILINGS GENERALLY IMPROVING TO VFR THROUGH THE MORNING.
SHOWERS AND STORMS EXPECTED TO INCREASE ACROSS THE AREA THROUGH
THE DAY AND CONTINUING IN SOME FASHION THROUGH THRU OVERNIGHT.
SURFACE WINDS MOSTLY ENE NEAR 10 KTS EXCEPT STRONGER AND GUSTY
NEAR THUNDERSTORMS.

//ATL CONFIDENCE...12Z UPDATE...
HIGH CONFIDENCE FOR IFR CIGS IMPROVING THIS MORNING AND WINDS.
LOW-MEDIUM CONFIDENCE ON TIMING AND IMPACTS OF THUNDERSTORMS.

BDL

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          83  69  84  70 /  60  60  70  20
ATLANTA         84  70  83  70 /  50  50  70  30
BLAIRSVILLE     81  67  81  65 /  50  50  70  20
CARTERSVILLE    86  69  85  70 /  50  50  70  30
COLUMBUS        85  72  87  73 /  50  50  70  40
GAINESVILLE     81  70  82  70 /  60  60  70  20
MACON           85  70  88  70 /  60  50  70  30
ROME            87  70  86  70 /  40  40  70  40
PEACHTREE CITY  84  70  84  69 /  50  50  70  40
VIDALIA         84  71  88  72 /  70  50  60  20

&&

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

SHORT TERM...11
LONG TERM....ARG
AVIATION...11

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1205 PM EDT SAT JUL 13 2013

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-141615-
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-
1205 PM EDT SAT JUL 13 2013

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

.DAY ONE...THIS AFTERNOON AND TONIGHT...

WEATHER HAZARDS EXPECTED...

...FLASH FLOOD WATCH IN EFFECT UNTIL EARLY SUNDAY MORNING FOR EASTERN GEORGIA...

PERIODS OF MODERATE TO LOCALLY HEAVY RAINFALL ARE STILL POSSIBLE
THROUGH TONIGHT...MAINLY ACROSS EASTERN GEORGIA. SOILS REMAIN SATURATED
AND FLOODING IS POSSIBLE.

THE STRONGER THUNDERSTORMS HAVE THE POTENTIAL TO PRODUCE FREQUENT
LIGHTNING...GUSTY WINDS...AND SMALL HAIL. WITH SATURATED
SOILS...IT WILL NOT TAKE MUCH WIND TO BLOW DOWN TREES. SOME
ISOLATED STORMS MAY BECOME SEVERE...PRODUCING WINDS IN EXCESS OF
60 MPH AND QUARTER SIZE HAIL.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...
SHOWERS AND THUNDERSTORMS WILL BECOME MORE SCATTERED AND DIURNAL
INTO NEXT WEEK. THERE WILL STILL BE PERIODS OF MODERATE TO
HEAVY RAINFALL IN THE STRONGER THUNDERSTORMS SO LOCALIZED FLOODING
WILL REMAIN A POSSIBILITY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT...HOWEVER
SPOTTERS ARE ENCOURAGED TO REPORT ANY HEAVY RAINFALL...FLOODING
OR SEVERE WEATHER.