• Atlanta, Georgia, United States (30301)
  • WxZone: GAZ045ICAO: KPDKLat: 33.79NLon: 84.19W

Discussions

905 PM EST TUE MAR 9 2010

.UPDATE...
NO CHANGES PLANNED AT THIS TIME.  TIMING OF PCPN AND TSRA APPEARS TO 
BE ON TRACK LOOKING UPSTREAM ACROSS AL. AM SOMEWHAT CONCERNED ABOUT 
ADVERTISED LOW TEMPS BEING REALIZED...BUT WITH DEWPOINTS STILL IN 
THE 30S...ONCE PCPN STARTS LATER...EVAPORATIVE COOLING SHOULD LOWER 
TEMPS INTO THE UPPER 40S TO NEAR 50.  THUS...WILL NOT MAKE ANY 
CHANGES AT THIS TIME. ELEVATED CONVECTION MAY YIELD SOME HEAVY RAIN 
WED. GIVEN THAT THE PAST FEW WEEKS HAVE BEEN RELATIVELY FREE OF 
HEAVY RAIN...WE SHOULD BE ABLE TO HANDLE THIS INITIAL ROUND. GREATER 
THREAT OF FLOODING...AS WELL AS SEVERE WEATHER...WITH SECOND 
ROUND...THU. CENTRAL U.S. UPPER LOW WILL GRADUALLY RELOCATE TO THE 
MID-ATLANTIC REGION BY THE WEEKEND...THEN LINGER THERE FOR SEVERAL 
DAYS...RESULTING IN AN EXTENDED PERIOD OF UNSETTLED...COOL WEATHER 
FOR THE CWA AFTER THU.

19
&&

.PREVIOUS DISCUSSION /ISSUED AT 540 PM EST/...

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
MODELS IN FAIRLY GOOD AGREEMENT CONCERNING THE LARGE SCALE FEATURES
THROUGH THE SHORT TERM FORECAST PERIOD. LARGE UPPER LOW EXPECTED TO
STALL OVER THE CENTRAL AND NORTHERN PLAINS THROUGH THURSDAY. GEORGIA
ENDS UP UNDER PERSISTENT SOUTHWESTERLY...DIFFLUENT...UPPER FLOW WITH
ABUNDANT MOISTURE STREAMING ACROSS THE REGION. FIRST WEAK SHORT WAVE
IN THE SOUTHWESTERLY FLOW SWEEPS ACROSS WEDNESDAY WITH A HEIGHTENED
FOCUS FOR SIGNIFICANT PRECIPITATION. A SECOND WAVE IS EXPECTED 
THURSDAY. RIGHT NOW INSTABILITY REMAINS ONLY MODERATE AT BEST WITH
WIDESPREAD SEVERE THUNDERSTORMS NOT EXPECTED AT THIS TIME. SEE
DISCUSSION BELOW CONCERNING HEAVY RAIN POTENTIAL.

.LONG TERM /FRIDAY THROUGH TUESDAY/...
DEEPER...RICHER...MOISTURE IS SWEPT EAST OF THE FORECAST AREA FRIDAY
AS THE UPPER LEVEL LOW AND ITS ASSOCIATED SURFACE LOW MOVE EAST INTO
THE EASTERN OHIO VALLEY. THIS SHOULD END OUR HEAVIER...MORE
WIDESPREAD...RAIN THREAT...BUT THE MODELS ARE STALLING THE LOWS ALONG
THE EAST COAST KEEPING THE FORECAST AREA UNDER COOLER NORTHWEST FLOW
FOR THE WEEKEND AND THE BEGINNING OF NEXT WEEK. MODELS ALSO SHOWING
DECENT MOISTURE WRAPPING AROUND THE EAST COAST SYSTEM FOR AT LEAST
SMALL PRECIPITATION CHANCES OVER NORTH GEORGIA THROUGH THE MAJORITY
OF THE EXTENDED FORECAST PERIOD.

20
&&

.HYDROLOGY...
MODELS ARE SHOWING A POTENTIAL FOR MODERATE TO HEAVY RAINFALL TOTALS
ACROSS PARTS OF NORTH AND CENTRAL GEORGIA WEDNESDAY THROUGH THURSDAY.
HOWEVER THERE DOES REMAIN SOME DIFFERENCE BETWEEN THE GFS...NAM AND
ECMWF CONCERNING WHERE THE HEAVIEST RAIN WILL BE DURING EACH PERIOD.
GFS HIGHLIGHTS HEAVIEST RAIN OVER NORTH GEORGIA WEDNESDAY AND CENTRAL
GEORGIA THURSDAY. WE HAVE HAD A PERIOD OF DRY WEATHER SINCE EARLY
LAST WEEK WHICH HAS ALLOWED THE UPPER SOILS TO DRY OUT SOME...AND
RIVER AND STREAM LEVELS HAVE LOWERED FROM THE CONSTANT HIGH FLOWS
EARLIER IN THE WINTER SEASON. ALTHOUGH WIDESPREAD FLOODING ISSUES ARE
NOT EXPECTED AT THIS TIME...THIS SITUATION WILL NEED TO BE WATCHED
CLOSELY FOR POSSIBLE WATCH ISSUANCE.

20
&&

.AVIATION...
GFS HAS A BETTER HANDLE ON THE PRECIP IN AL HEADED THIS WAY.  NAM IS 
TOO SLOW.  AHEAD OF THIS PRECIP...VIRGA WILL CONTINUE ACROSS THE 
STATE AS DRY...LOW-LEVEL AIR PERSISTS THIS EVENING.  MAY SEE 
PRECIP FINALLY REACH THE GROUND BY 06Z AS DEEPER ACTIVITY IN AL 
FINALLY ENTERS THE STATE.  VSBYS WILL STAY ABOVE 6SM UNTIL RAIN 
STARTS...BUT EVEN THEN...SHOULD REMAIN MVFR.  CIGS WILL GRADUALLY 
LOWER ALL EVENING...EVENTUALLY BECOMING MVFR AROUND 10Z.  WILL NOT 
INTRODUCE TSRA UNTIL AFTER 18Z...AND EVEN THAT LOOKS UNLIKELY.  JUST 
CAN'T RULE OUT SOME ELEVATED CONVECTION LATE IN THE DAY...SO WILL 
PROBABLY HAVE CB MENTIONED.  WINDS WILL BE THE TRICKIEST WITH 
PENDULUM SWINGS BETWEEN 190 AND 170 ALREADY OCCURRING AT ATL.  AM 
EXPECTING THESE WINDS TO GRADUALLY SWING TO EASTERLY BY 00Z AND STAY 
THAT WAY FOR A COUPLE DAYS.

27
&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          49  58  51  67  53 /  60  80  80  80  30 
ATLANTA         50  59  52  68  52 /  70  90  80  80  30 
BLAIRSVILLE     47  55  48  62  50 /  70  80  80  80  30 
CARTERSVILLE    49  59  51  67  50 /  80  90  80  80  30 
COLUMBUS        52  64  55  72  56 /  80  80  80  70  40 
GAINESVILLE     50  58  51  66  52 /  70  90  80  80  30 
MACON           50  64  55  71  56 /  60  80  80  80  40 
ROME            49  59  50  67  49 /  70  90  80  70  30 
PEACHTREE CITY  49  60  52  69  51 /  80  90  80  70  30 
VIDALIA         49  71  56  71  58 /  30  60  80  80  40 

&&

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

$$

20/27/19
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