Area Forecast Discussion
Issued by NWS Atlanta, GA

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FXUS62 KFFC 021130
AFDFFC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
730 AM EDT THU JUL 2 2015



.PREV DISCUSSION... /ISSUED 352 AM EDT THU JUL 2 2015/

SHORT TERM /TODAY THROUGH FRIDAY/...
SHORT TERM PERIOD CONTINUES TO BE MARKED BY ACTIVE PATTERN AS A
SERIES OF UPPER LEVEL DISTURBANCES IN A DIRTY NORTHWEST FLOW FUNNEL
INTO THE SOUTHEAST. THE INTERACTION OF THESE DISTURBANCES WITH A
MOIST...UNSTABLE ATMOSPHERE WILL CONTINUE TO PRODUCE WIDESPREAD
SHOWERS AND THUNDERSTORMS. HI-RES SHORT TERM MODELS CONTINUE TO HAVE
DIFFICULTY RESOLVING CONVECTION TRENDS...WITH NONE OF THE MODELS
REALLY HAVING A GOOD HANDLE ON THE SITUATION. EXPECT BEST COVERAGE
AND HIGHEST SEVERE POTENTIAL TO BE THIS AFTERNOON AND EVENING...AND
GENERALLY NORTH OF A LA GRANGE TO MACON TO SWAINSBORO LINE.
HOWEVER...ISOLATED SEVERE STORMS ARE STILL POSSIBLE OUTSIDE OF THIS
AREA.

THE MAIN THREATS CONTINUE TO BE STRONG...DAMAGING WINDS AND FREQUENT
LIGHTNING. HAIL UP TO 1 INCH IS ALSO POSSIBLE. ANOMALOUS MODELED
PRECIPITABLE WATER VALUES CONTINUE TO SUGGEST THAT LOCALLY HEAVY
RAINFALL MAY POSE A FLASH FLOOD RISK...PARTICULARLY OF LOW LYING AND
FLOOD PRONE AREAS. SPC DOES HAVE MUCH OF NORTH AND CENTRAL GEORGIA
IN A MARGINAL RISK FOR SEVERE STORMS FOR TODAY...WITH A SMALL SLIVER
OF NORTHWEST GEORGIA IN THE HIGHER SLIGHT RISK AREA.

ON A SIDE NOTE...NCAR ENSEMBLE FORECAST 1 KM REFLECTIVITY SEEMED TO
DO WELL WITH OVERALL CONVECTION TRENDS WEDNESDAY AND WEDNESDAY
NIGHT. THE 00Z RUN SEEMS TO PARALLEL CURRENT FORECAST THINKING WITH
BEST POPS STAYING ACROSS THE FAR NORTHERN ZONES. HAVE UNDER-UTILIZED
THIS PRODUCT IN THE PAST AND CAN NOT SPEAK TO ITS OVERALL SKILL IN
THIS ENVIRONMENT YET.

STORMS ARE EXPECTED TO DIMINISH SOMEWHAT OVERNIGHT...AND HAVE SCALED
BACK DAYTIME/EVENING LIKELY POPS TO LIKELY IN THE FAR NORTH...AND
THEN JUST GOOD CHANCE EARLY FRIDAY MORNING. ACTIVE PATTERN CONTINUES
FRIDAY...THOUGH STORM COVERAGE SEEMS LESS IMPRESSIVE AS OF NOW. HAVE
OPTED TO CONTINUE WITH SLIGHTLY LESS POPS FOR FRIDAY...BUT STILL IN
THE GOOD CHANCE TO LIKELY CATEGORIES.

OVERALL...NEAR NORMAL TEMPERATURES ARE EXPECTED THROUGH THE SHORT
TERM...AND HAVE GONE WITH A BLEND OF GUIDANCE FOR BOTH HIGHS AND
LOWS.

31

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
NO MAJOR CHANGES WERE MADE TO THE EXTENDED PERIODS. THE MID AND
LONG RANGE MODELS CONTINUE TO SHOW AN ACTIVE PATTERN THROUGH THE
WEEKEND AS DISTURBANCES MOVE THROUGH THE BASE OF A LONG WAVE
TROUGH PARKED OVER THE AREA. MODERATE CAPE VALUES OF 2000-2500
J/KG CONTINUE TO SUPPORT SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS EACH AFTERNOON AND EVENING OVER THE WEEKEND... AND
WITH ADDED FORCING FROM OUTFLOWS AND UPPER DISTURBANCES... A FEW
SEVERE STORMS CANNOT BE RULED OUT. HOWEVER... DEEP LAYER SHEAR
VALUES OF 15-20KTS REMAIN RATHER MODEST... SUGGESTING MOST STORMS
SHOULD HOLD BELOW SEVERE LIMITS FOR THE MOST PART. THE BEST CHANCE
FOR A FEW STRONG TO SEVERE STORMS WILL BE FROM MID AFTERNOON
THROUGH EARLY EVENING WHEN CAPE AND SHEAR VALUES ARE EXPECTED TO
PEEK. ISOLATED TO SCATTERED CONVECTION WILL LIKELY LINGER
OVERNIGHT AS DISTURBANCES CONTINUE TO TRAVERSE THE AREA... BUT ANY
STRONG TO SEVERE STORM THREAT SHOULD END BY MID TO LATE EVENING
WITH LOSS OF DAYTIME HEATING.

BOTH GFS AND ECMWF ARE SHOWING THE UPPER TROUGH WEAKENING AND
SHEARING EASTWARD BY MONDAY... WITH WEAK RIDGING POSSIBLY
SETTLING OVER THE DEEP SOUTH FOR MONDAY THROUGH WEDNESDAY. WILL
REMAIN OPTIMISTIC... AND JUST SHOW A LOW CHANCE OF POPS EACH DAY
AS THE TYPICAL SUMMERTIME ISOLATED TO LOW SCATTERED COVERAGE OF
AFTERNOON STORMS ARE STILL EXPECTED.

39

&&

.AVIATION...
12Z UPDATE...
GENERALLY VFR CONDITIONS EXPECTED THROUGH THE PERIOD. SOME
LOCALIZED IFR POSSIBLE THROUGH 14Z. SW-W WINDS AT 6-10KT TODAY
WITH HIGHER GUSTS EXPECTED. SPEEDS WILL REMAIN 4-8KT OVERNIGHT.
VRB WINDS WITH GUSTS TO 25KT POSSIBLE IN/NEAR CONVECTION. LIGHT
RAIN SHOWERS EXITING NORTHEAST GEORGIA...BUT ALREADY SEEING SOME
ADDITIONAL AREAS OF DEVELOPMENT. BEST TS CHANCES WILL BE 18-00Z.

//ATL CONFIDENCE...12Z UPDATE...
MEDIUM TO HIGH CONFIDENCE ON ALL ELEMENTS.

31

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          86  69  87  70 /  60  40  50  40
ATLANTA         85  70  85  71 /  60  50  50  40
BLAIRSVILLE     78  66  78  64 /  80  70  60  60
CARTERSVILLE    84  70  84  68 /  70  70  60  50
COLUMBUS        88  73  91  72 /  60  30  40  40
GAINESVILLE     82  68  83  69 /  60  60  60  40
MACON           89  72  90  71 /  50  30  40  40
ROME            84  70  85  69 /  70  70  60  50
PEACHTREE CITY  86  70  86  70 /  60  50  50  40
VIDALIA         92  74  92  73 /  40  30  40  30

&&

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

$$

SHORT TERM...31
LONG TERM....39
AVIATION...31


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