Area Forecast Discussion
Issued by NWS Atlanta, GA

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FXUS62 KFFC 020330
AFDFFC

AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1029 PM EST SUN MAR 1 2015

.EVENING UPDATE...
AREA WINDS ARE SWINGING AROUND MORE SOUTHERLY NOW AND HELPING TO
ERODE THE EFFECTS OF THE COOL WEDGE. THIS HAS WARRANTED BUMPING UP
THE EXPECTED LOWS BY A FEW DEGREES OR MORE. OTHERWISE... STILL
EXPECT AREAS OF LIGHT RAIN... DRIZZLE AND PATCHY FOG TO PREVAIL
THROUGH MONDAY MORNING... SO ONLY MADE ADJUSTMENTS TO THE LOW TEMPS
AT THIS TIME.  /39


.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
/ISSUED AT 258 PM EST SUN MAR 1 2015/
WEDGE HOLDING THIS AFTERNOON WITH WIDESPREAD CLOUDS AND PATCHES OF
RAIN/DRIZZLE. HIGH PRESSURE SHOULD BE WEAKENING OVERNIGHT WITH
DECREASING EASTERLY FLOW...HOWEVER LOWER LAYERS OF THE ATMOSPHERE
REMAIN SATURATED AND SHOULD HAVE LOW CLOUDS WITH SOME FOG/DRIZZLE
THROUGH THE NIGHT. NO OBVIOUS FEATURES TO KEY IN ON...BUT RAIN
COMING ACROSS AL INTO NORTH GA MAY BE WITH A WEAK SHORT WAVE SO HAVE
HIGHEST POPS IN THAT AREA THROUGH TONIGHT.  UPPER FLOW GOES MOSTLY
ZONAL TO WEST/SOUTHWEST MONDAY AND MONDAY NIGHT. THIS KEEPS THE
NORTH IN A ZONE OF DEEPER MOISTURE AND WEAK WAVES SO HAVE KEPT
HIGHER POPS NORTH...DECREASING INTO CENTRAL GEORGIA MONDAY AND
MONDAY NIGHT.

TEMPERATURE TREND SHOULD BE NEARLY STEADY OVERNIGHT AND HAVE TRIED
TO ADJUST FOR THIS. AT LEAST NO FREEZING TEMPERATURES IN THE
FORECAST.

41


.LONG TERM /TUESDAY THROUGH SUNDAY/...
/ISSUED AT 258 PM EST SUN MAR 1 2015/
START TUESDAY WITH ANOTHER WEDGE IN PLACE SO HAVE BROUGHT
TEMPERATURES DOWN ACROSS THE NE BELOW GUIDANCE. STILL LOOKING AT A
SLOW MOVING FRONT MOVING INTO THE CWA ON WEDNESDAY WITH THE GFS THE
FASTEST SOLUTION AND THE NAM THE SLOWEST. HAVE GONE AHEAD AND BUMPED
UP POPS INTO THE CATEGORICAL RANGE FOR WEDNESDAY AND WEDNESDAY NIGHT
ACROSS THE NORTH SINCE GUIDANCE IS VERY SLOW WITH PUSHING THE FRONT
THROUGH. STILL LOOKING AT A CHANCE OF THUNDERSTORMS IN THE FORECAST
TUESDAY NIGHT INTO WEDNESDAY...WITH THE BEST CHANCES ACROSS NORTH
AND THE NORTHERN PORTIONS OF CENTRAL GEORGIA ON WEDNESDAY WITH
MUCAPE VALUES AROUND 300 J/KG /JUST SLIGHTLY LESS THAN YESTERDAY/.
NOT QUITE AS MUCH AREA WITH 40KTS OF LOW LEVEL SHEAR BUT STILL
SOMETHING TO WATCH.

MODELS ARE PERSISTENT WITH BRINGING IN FREEZING TEMPERATURES TO THE
NORTHWEST LATE WEDNESDAY NIGHT INTO THURSDAY MORNING...WHILE
CONTINUING PRECIPITATION. STILL THINK TEMPS MAY BE A BIT ON THE
COOLER SIDE SO HAVE ADJUSTED UPWARD A BIT...BUT THIS STILL LEAVES
SOME LOW TEMPS AT OR BELOW FREEZING THURSDAY MORNING. BUFR
SOUNDING AT KCHA SHOWS A BRIEF PERIOD OF FREEZING RAIN WEDNESDAY
NIGHT FOLLOWED BY SLEET AND THEN SNOW BY 12Z THURSDAY AS THE
COLUMN COOLS. THE BUFR SOUNDING AT BRASSTOWN IS SIMILAR BUT
SLIGHTLY DELAYED AND KEEPS THE POTENTIAL FOR SNOW INTO MID
THURSDAY MORNING. GIVEN THIS AND SURFACE TEMPS...HAVE GONE AHEAD
AND MENTIONED SNOW/SLEET LATE WEDNESDAY NIGHT INTO THURSDAY
MORNING FOR PARTS OF NORTH GEORGIA...MAINLY THE NW. WILL NEED TO
WATCH THIS TIME PERIOD CLOSELY AS THE GFS BUFR SOUNDING EVEN HINTS
AT BRINGING SOME FREEZING RAIN TRANSITIONING TO SLEET INTO THE
METRO AREA THURSDAY MORNING. TEMPS ARE A LITTLE TOO WARM TO
MENTION IT THAT FAR SOUTH IN THE GRIDS YET...BUT AGAIN SOMETHING
THAT NEEDS TO BE WATCHED CLOSELY.

PRECIP SHOULD PUSH OUT BY FRIDAY AND HAVE LEANED TOWARDS THE DRIER
GFS FOR THE REMAINDER OF THE LONG TERM.

PREVIOUS LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... WARM PATTERN
STILL APPEARS TO BE IN STORE FOR THE REGION TO START OUT THE
EXTENDED FORECAST PERIOD AS UPPER-LEVEL FLOW BECOMES STRONG
SOUTHWESTERLY AHEAD OF THE WESTERN U.S. TROUGH. CANNOT RULE OUT SOME
CHANCE FOR PRECIPITATION MONDAY NIGHT THROUGH TUESDAY NIGHT WITH
AMPLE MOISTURE AND THE POTENTIAL FOR WEAK MID/UPPER-LEVEL SHORT
WAVES EJECTING FROM THE DEEP TROUGH. HOWEVER THE LACK OF LOW-LEVEL
FORCING AND THE UNCERTAIN NATURE OF THE TIMING ANY OF THESE
TRANSIENT MID/UPPER FEATURES LEADS ME TO KEEP POPS CHANCE AT BEST
THROUGH THAT TIME FRAME. STRONG SURFACE TROUGH ASSOCIATED WITH THE
APPROACHING UPPER TROUGH WEDNESDAY THROUGH WEDNESDAY NIGHT BRINGS
THE BEST CHANCES FOR ORGANIZED PRECIPITATION TO THE FORECAST AREA
WITH SUFFICIENT INSTABILITY FOR AT LEAST SCATTERED THUNDERSTORMS.
INSTABILITY IS WANING SOME AS THE FRONT PUSHES IN BUT IS HIGH ENOUGH
WHEN COMBINED WITH RELATIVELY STRONG LOW/MID-LEVEL WINDS TO KEEP US
ON OUR TOES FOR AT LEAST SOME MARGINAL ISOLATED SEVERE POTENTIAL.
STILL TOO UNCERTAIN TO INCLUDE ANY MENTION RIGHT NOW. GFS...AND TO A
LESSER EXTENT THE ECMWF...CONTINUE TO BRING IN FAIRLY COLD AIR INTO
THE FORECAST AREA WEDNESDAY NIGHT WHILE KEEPING SOME LIGHT QPF OVER
THE REGION THROUGH THURSDAY. WITH THE MAIN UPPER TROUGH LIFTING AND
FILLING SOME AS IT SWEEPS THROUGH I AM STILL A BIT LEARY THAT THE
BEST COLD AIR WILL MAKE TOO BIG OF AN INTRUSION INTO THE AREA VS
GETTING SHUNTED OFF TO THE EAST. I HAVE BEEN LEANING TOWARD THE
SLIGHTLY WARMER AND DRIER ECMWF THE PAST FEW RUNS AND AM INCLINED TO
CONTINUE THAT TREND IN LIGHT OF THE LATEST COUPLE OF RUNS OF THE GFS
ALSO SHOWING THIS SAME TREND IN FLATTENING THE FLOW ACROSS THE
REGION IN THE WAKE OF THE LIFTING UPPER TROUGH.

20

&&

.AVIATION...
00Z UPDATE... EXPECT CURRENT IFR CIGS TO LOWER BACK DOWN TO LIFR
LEVELS BY 02-03Z THIS EVENING. MAY SEE A BRIEF IMPROVEMENT TO IFR
LEVELS BETWEEN 05-07Z TONIGHT AS HIRES MODELS SHOW SOME CONVECTIVE
SHOWERS PUSHING ACROSS THE ATLANTA TAF SITES AROUND THEN... BUT CIGS
SHOULD SETTLE BACK DOWN TO LIFR LEVELS WITH -DZ AS THE CONVECTION
MOVES EAST. EXPECT A SLOW IMPROVEMENT AFTER 15Z MONDAY WITH SCATTERD
SHOWERS ALONG AND BEHIND A COLD FRONT THAT SAGS ACROSS THE ATLANTA
TAF SITES BY 18-20Z MONDAY. CURRENT LIGHT EASTERLY WINDS WILL VEER
MORE SE BY 03-05Z... THEN SW BY 07-09Z... THEN WNW BY 18-20Z MON.
SPEEDS ALL GENERALLY 6KTS OR LESS.

//ATL CONFIDENCE...00Z UPDATE...
MEDIUM ON ALL ELEMENTS.

39

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          40  61  46  52 /  50  30  50  50
ATLANTA         41  55  45  61 /  40  30  50  40
BLAIRSVILLE     41  55  42  50 /  60  60  50  60
CARTERSVILLE    43  50  42  59 /  50  50  40  50
COLUMBUS        43  61  50  74 /  20  30  30  30
GAINESVILLE     42  52  43  50 /  50  40  50  60
MACON           42  61  53  70 /  20  20  30  30
ROME            45  50  42  61 /  60  60  40  60
PEACHTREE CITY  42  55  47  65 /  40  30  40  40
VIDALIA         43  65  56  71 /  20  20  20  30

&&

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

$$

SHORT TERM...41/39
LONG TERM....11
AVIATION...39


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