Special Weather Statement, NWS Atlanta, GA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
136 PM EDT TUE AUG 18 2015

.UPDATE...
/ISSUED AT 1111 AM EDT TUE AUG 18 2015/
HAVE MADE TWEAKS TO POPS/WX BASED UPON CURRENT RADAR TRENDS. AREA
OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO SPREAD ACROSS
NORTHWEST AND NORTH GA. NOT SEEING THE AREA OF SHOWERS SPREAD TOO
FAR TO THE SOUTH AND HAVE PULLED BACK ON THE POPS/THUNDER ALONG
AND SOUTH OF I-85 THROUGH EARLY AFTERNOON. UPDATED FORECAST
ALREADY ISSUED.

&&

.PREV DISCUSSION... /ISSUED 353 AM EDT TUE AUG 18 2015/

SHORT TERM /TODAY THROUGH WEDNESDAY/...
MODELS IN GOOD AGREEMENT THROUGH THE SHORT TERM WITH A VERY GOOD
GULF CONNECTION SPREADING DEEP MOISTURE OVER THE CWA. THIS WILL
CONTINUE INTO WEDNESDAY KEEP SCATTERED TO WIDESPREAD SHOWERS AND
TSTORMS OVER THE CWA. THE BEST CHANCES WILL BE ACROSS NORTH GEORGIA
AND MAINLY DURING THE AFTERNOON AND EVENING HOURS. ALTHOUGH THUNDER
WILL BE MINIMAL EARLY THIS MORNING AND ALSO WEDNESDAY MORNING...
EXPECT THUNDER TO BECOME MORE NUMEROUS WITH DAYTIME HEATING THIS
AFTERNOON AND INTO THE EARLY EVENING HOURS. ALTHOUGH THE GREATEST
INSTABILITY WILL BE ACROSS NORTH GA...AN ISOLATED STRONG TO SEVERE
STORM WILL BE POSSIBLE JUST ABOUT ANYWHERE THIS AFTERNOON AND
EVENING WITH THE MAIN THREAT BEING STRONG WINDS. TEMPERATURES
THROUGH WEDNESDAY WILL BE PRETTY CLOSE TO PERSISTENCE DUE TO
CLOUDS AND PRECIP...AND THE MODELS HAVE A GOOD HANDLE ON THIS.

17

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
PATTERN IN LONG TERM PERIOD TRANSITIONS FROM HIGH AMPLITUDE TROUGH
ALONG THE MS RIVER VALLEY STATES ON WED TO ZONAL FLOW THIS WEEKEND
AND FINALLY WEAK NW FLOW/UPR RIDGE TO THE WEST WITH A HINT OF A
MDT FROPA ON MONDAY. WITH THE FIRST TWO PATTERNS...SE CONUS SHOULD
REMAIN IN MOIST PATTERN WITH DEEP MOISTURE THRU THE WEEKEND. NO
ONE DAY SEEMS TO STAND OUT WITH PRECIP CHCS NOR DO ANY DAYS SEEM
TO HAVE CHC FOR SVR OR EVEN STRONG DEEP CONVECTION. MED RANGE
MODELS IN GOOD AGREEMENT. WPC PREFERRING BLEND OF ALL 00Z
OPERATIONAL MODELS FOR FEATURES AFFECTING CWA THRU DAY 7.

TROPICAL ACTIVITY REMAINS SUBDUED. COLD CORE UPPER LOW OFF
CAROLINA COAST...WHICH HAS PLAYED A ROLE IN CREATING STAGNANT
PATTERN OF LATE AND MAY BECOME TROPICAL IN NATURE...SHOULD GET
PICKED UP BY UPPER TROUGH THIS WEEKEND AND LIFT AWAY FROM EAST
COAST. LOW LATITUDE DISTURBANCE AT 35W LONGITUDE THAT TPC IS
TRACKING COULD DEVELOP INTO A NAMED STORM BUT PROGGED TO REMAIN ON
WESTERLY COURSE WITH MEAGER INTENSITY BY ECMWF AND GFS. BY NO
MEANS A GUARANTEE BUT THATS THE LATEST 411.

SNELSON

&&

.AVIATION...
18Z UPDATE...
DEEP TROPICAL AIR MASS IN PLACE WILL RESULT IN WIDESPREAD SHOWERS
WITH SCATTERED EMBEDDED THUNDERSTORMS THROUGH THE EVENING... WITH
ISOLATED SHOWERS LINGERING OVERNIGHT. EXPECT A REPEAT OF WIDESPREAD
CONVECTION AGAIN ON WEDNESDAY WITH DAYTIME HEATING. VFR CIGS WILL
PREVAIL THROUGH THE EVENING... THEN A MIX OF IFR/MVFR CIGS WILL
SPREAD OVER ALL TAF SITES BY 08-10Z WED IF NOT SOONER. CIGS WILL
IMPROVE TO VFR LEVELS BY 17-18Z WED. WINDS WILL REMAIN SOUTHWEST...
GENERALLY 10KTS OR LESS WITH STRONG GUSTS AROUND CONVECTION.

//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON TIMING OF IFR/MVFR CIGS TONIGHT AND IMPROVEMENT TO VFR ON WED
HIGH ON REMAINING ELEMENTS

39

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          86  70  87  73 /  70  70  70  30
ATLANTA         87  72  85  74 /  70  70  70  30
BLAIRSVILLE     81  68  82  68 /  80  80  70  50
CARTERSVILLE    83  71  85  72 /  80  80  70  50
COLUMBUS        88  74  88  75 /  70  70  70  30
GAINESVILLE     83  71  84  72 /  80  80  70  40
MACON           91  72  89  74 /  70  70  70  20
ROME            83  71  85  72 /  80  80  70  60
PEACHTREE CITY  88  72  85  73 /  70  70  70  30
VIDALIA         89  74  92  75 /  70  60  70  30

&&

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

SHORT TERM...ATWELL/39
LONG TERM....BAKER
AVIATION...39

HAZARDOUS WEATHER OUTLOOK...UPDATE
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1202 PM EDT TUE AUG 18 2015

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-191130-
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-
1202 PM EDT TUE AUG 18 2015

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

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

A VERY MOIST AND MODERATELY UNSTABLE ENVIRONMENT WILL RESULT IN
WIDESPREAD SHOWERS AND SCATTERED THUNDERSTORMS DEVELOPING ACROSS
NORTH AND CENTRAL GEORGIA THIS AFTERNOON AND EVENING. SOME OF THE
THUNDERSTORMS COULD BE STRONG... OR EVEN BRIEFLY SEVERE.

WEATHER HAZARDS EXPECTED...

THE MAIN STORM THREATS WILL BE WIND GUSTS TO 50 MPH... FREQUENT
LIGHTNING AND PERIODS OF VERY HEAVY RAIN THAT COULD CAUSE BRIEF
FLOODING ALONG LOW LYING FLOOD PRONE AREAS. THE MORE FAVORABLE TIME
FOR STRONG STORMS WILL BE BETWEEN 2 PM AND 10 PM TODAY.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY...
SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE THROUGH MONDAY.
HEAVY RAINFALL...GUSTY WINDS AND LIGHTNING WILL BE THE LIKELY
HAZARDS.

.SPOTTER INFORMATION STATEMENT...

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

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
143 PM EDT TUE AUG 18 2015

GAZ022-023-033>035-181815-
NORTH FULTON GA-GWINNETT GA-BARROW GA-FORSYTH GA-HALL GA-
143 PM EDT TUE AUG 18 2015

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN NORTH FULTON...
NORTHERN GWINNETT...NORTHWESTERN BARROW...FORSYTH AND SOUTHWESTERN
HALL COUNTIES UNTIL 215 PM EDT...

AT 142 PM EDT...A STRONG THUNDERSTORM WAS OVER SUWANEE...OR 9 MILES
NORTHWEST OF LAWRENCEVILLE...MOVING NORTHEAST AT 30 MPH.

  HAZARD...WINDS UP TO 40 MPH AND HEAVY RAIN.

  IMPACT...PEOPLE OUTDOORS SHOULD SEEK SHELTER IMMEDIATELY. EXPECT
           MINOR DAMAGE TO TREE LIMBS AND BLOWING AROUND OF
           LIGHT...UNSECURED OBJECTS. LOCALIZED FLOODING IN LOW
           LYING AND POOR DRAINAGE AREAS IS ALSO LIKELY. MOTORISTS
           SHOULD SLOW DOWN AND BE PREPARED FOR POSSIBLE LOSS OF
           CONTROL DUE TO HYDROPLANING. WHEN WATER COVERS THE
           ROAD...REMEMBER TO TURN AROUND DON'T DROWN.

SOME LOCATIONS IN THE PATH OF THIS STORM INCLUDE
LAWRENCEVILLE...JOHNS CREEK...ALPHARETTA...DULUTH...SUGAR HILL...
SUWANEE...BUFORD...BRASELTON...AUBURN...FLOWERY BRANCH...DACULA...
OAKWOOD...BERKELEY LAKE...REST HAVEN...BUFORD DAM-LAKE LANIER
PARKS...AQUALAND PARK...CHATEAU ELAN...COUNTY LINE...LAKE LANIER
ISLANDS AND BROOKWOOD.

LAT...LON 3413 8381 3413 8382 3411 8382 3410 8379
      3409 8379 3407 8377 3406 8374 3404 8372
      3393 8415 3409 8424 3428 8396
TIME...MOT...LOC 1742Z 245DEG 28KT 3405 8411

DJN