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AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
550 PM EST WED DEC 14 2005
.SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT)
CAD WEDGE HAS BEEN STRENGTHENING THROUGH THE DAY AS LOWER DEWPOINTS HAVE FILTERED IN FROM THE NORTHEAST. TEMPERATURES AND DEWPOINTS UPSTREAM ARE A BIT WORRISOME...ESPECIALLY GIVEN THE POTENTIAL FOR EVAPORATIVE COOLING. SOME PRECIPITATION HAS ALREADY BEGUN ACROSS THE NORTHERN HALF OF THE CWA...WE HAVE RECEIVED SCATTERED REPORTS OF LIGHT SLEET AND SNOW FLURRIES THROUGH THE LATE MORNING AND EARLY AFTERNOON HOURS...NOT SURPRISING GIVEN THE PROFILE AND THE EXPECTED EVOLUTION OF THE ATMOSPHERE THROUGH THE DAY. THIS WILL CONTINUE THROUGH THE REST OF THE AFTERNOON AND INTO THE EVENING...WITH TEMPERATURES STEADY FOR A WHILE THEN SLOWLY DECREASING.
DEWPOINT DEPRESSIONS IN NORTHEAST GEORGIA ARE HIGH ENOUGH THAT EVAPORATIVE COOLING MAY QUICKLY ALLOW TEMPERATURES TO FALL TO THE FREEZING MARK AGAIN. TEMPS SHOULD THEN HOVER NEAR THE FREEZING LEVEL MOST OF THE NIGHT IN THE LEE OF THE MOUNTAINS...WHILE FOR MOST OF THE REST OF THE AREA TEMPS SHOULD REMAIN ABOVE FREEZING. EXACT TEMPERATURES WILL BE DIFFICULT TO PINPOINT AND WILL DEPEND ON ONSET OF PRECIPITATION...HOW LONG IT TAKES TO REACH SATURATION...AND HOW WARM TEMPERATURES ACTUALLY GET TODAY...AMONG OTHER THINGS. MEANWHILE...PRECIPITATION SHOULD BEING IN EARNEST THIS EVENING AND EARLY TONIGHT. OF COURSE...THE FIRST BIT OF QPF /PERHAPS NOT QUITE THE TYPICAL QUARTER OF AN INCH OR SO/ WILL GO INTO EVAPORATIVE COOLING. MOST OF THE PRECIP SHOULD BE RAIN...BUT WOULD NOT BE SURPRISED TO SEE A CONTINUED MIX ACROSS THE AREA...BUT ANYTHING THAT DOES FALL AS FREEZING OR FROZEN PRECIPITATION WILL MELT AND NO IMPACTS WILL BE FELT...EXCEPT IN NORTHEAST GEORGIA. AN UPDATED SPS WILL BE ISSUED TO DISCUSS THE SITUATION.
ALSO...WILL ISSUE A WINTER WEATHER ADVISORY FOR A FEW COUNTIES IN THE CLIMATOLOGICALLY PREFERRED CAD AREA. WITH TEMPERATURES HOVERING NEAR FREEZING...AND WBZ`S BELOW FREEZING UNTIL NEAR 12Z THURSDAY... THE GRADIENT OF WBZ`S BETWEEN THE SURFACE AND TREETOP LEVEL WOULD BE PLENTY TO ALLOW FOR SOME MINOR ACCUMULATIONS OF ICE ON TREES AND POWERLINES. PRE-EXISTING WARM GROUND TEMPERATURES WOULD PRECLUDE ANY ROAD OR TRAVEL PROBLEMS FOR THE MOST PART...EXCEPT PERHAPS ON A FEW EXPOSED BRIDGES AND OVERPASSES. NOMOGRAM THICKNESSES FOR THE GVL AREA /AND NATURALLY AREAS NORTH AND EAST WOULD BE COOLER/ BEGIN IN THE "WINTRY MIXTURE" AREA...CROSS INTO FREEZING RAIN/RAIN...AND FINALLY INTO RAIN BY THURSDAY MORNING. WBZ`S ARE USED TO DELINEATE BETWEEN FREEZING RAIN OR RAIN AND THESE ARE BELOW FREEZING FOR THE MOST PART OVERNIGHT...HENCE THE NEED FOR A WINTER WEATHER ADVISORY. AGAIN...ACCUMULATIONS ARE EXPECTED TO REMAIN ONLY AT NUISANCE LEVELS...BELOW 1/4 INCH.
OF THE GFS AND THE NAM...THE GFS IS THE MORE PREFERRED TRACK OF THE SURFACE LOW AS IT MOVES NORTHEAST /NAM HAS A LOT OF CONVECTIVE PRECIP ALONG THE COAST THAT HAS YET TO MATERIALIZE/...BUT HAVE STILL OPTED TO SLOW IT DOWN SOMEWHAT AND ADJUST THE CIRCULATION CENTER FURTHER TO THE SOUTHEAST TOWARDS THE BAROCLINICITY OF THE COASTAL AREAS /A MORE TYPICALLY PREFERRED TRACK OF COASTAL LOWS/. EROSION SEEMS TO BE TOO FAST...SO HAVE KEPT POPS IN FOR MOST OF THE DAY THURSDAY. HOWEVER... MOSTLY CLEAR FOR FRIDAY. TEMPERATURES THURSDAY WILL BE TOTALLY DEPENDENT UPON HOW QUICKLY THE PARENT HIGH MOVES OFF THE EAST COAST...HOW QUICKLY THEN THE CAD WEDGE ERODES...AND IF THERE IS ANY WRAPAROUND PRECIPITATION. FOR NOW...UPPER 30S NORTHEAST...AND POTENTIAL FOR NEAR 60 SOUTHERN ZONES. NEAR FREEZING THURSDAY NIGHT. 40S AND 50S FOR FRIDAY...AND COOLING AGAIN FRIDAY NIGHT WITH 20S AND 30S.
THANKS MRX/GSP/CAE/CHS FOR COLLABORATION WITH THIS EVENT.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
HIGH PRESSURE BUILDS IN FROM THE WEST WHILE ANOTHER COASTAL LOW DEVELOPS ALONG THE GULF COAST. IT SPREADS PRECIPITATION ACROSS THE AREA MAINLY ON SUNDAY...PARTS OF NORTH GEORGIA MAY SEE SOME SNOW EARLY THAT MORNING. FAIRLY SIGNIFICANT TROUGH DEVELOPS OVER THE EAST COAST TUESDAY INTO WEDNESDAY...WHILE YET MORE MOISTURE IS PULLED INTO THE AREA FROM ANOTHER GULF COAST SYSTEM. STRONG NORTHWEST FLOW BEHIND THIS MAY ALLOW TEMPERATURES TO COOL ENOUGH TO BRING SNOW AGAIN TO NORTHERN GEORGIA...BUT FOR NOW ONLY RAIN IN THE FORECAST TUESDAY NIGHT INTO WEDNESDAY. HIGHS 40S AND 50S...LOWS 20S AND 30S.
&&
Brent wrote:36 with a DP of 23 in Atlanta... this could be really bad for North Georgia. The mets there are really downplaying it for the city itself...
URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
648 PM EST WED DEC 14 2005
...WINTER WEATHER POSSIBLE IN PARTS OF NORTHEAST GEORGIA...
.A WEDGE OF COLD DRY AIR HAS BUILT DOWN THE EASTERN SEABOARD... ALLOWING TEMPERATURES IN NORTHEAST GEORGIA TO HOVER JUST ABOVE FREEZING DURING THE EVENING. AS MOISTURE INCREASES FROM A STORM SYSTEM APPROACHING FROM THE WEST...PRECIPITATION MAY BEGIN THIS EVENING AS A WINTRY MIXTURE...AND CHANGE OVER TO RAIN OR FREEZING RAIN DURING THE OVERNIGHT AND EARLY THURSDAY MORNING HOURS.
GAZ006>009-013-021-025-027-032>037-045>047-150800-
/O.NEW.KFFC.WW.Y.0002.051215T0000Z-051215T1500Z/
FANNIN-GILMER-UNION-TOWNS-PICKENS-CHEROKEE-JACKSON-MADISON-COBB-
NORTH FULTON-GWINNETT-BARROW-CLARKE-OCONEE-DEKALB-ROCKDALE-WALTON-
INCLUDING THE CITIES OF...MARIETTA...ATLANTA...LAWRENCEVILLE...
ATHENS...DECATUR...CONYERS
648 PM EST WED DEC 14 2005
...WINTER WEATHER ADVISORY IN EFFECT UNTIL 10 AM EST THURSDAY...
THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A
WINTER WEATHER ADVISORY...WHICH IS IN EFFECT UNTIL 10 AM EST
THURSDAY.
PRECIPITATION WILL BEGIN THIS EVENING LIKELY AS A PERIOD OF RAIN MIXED WITH LIGHT SLEET. ONCE TEMPERATURES BEGIN TO DROP...THEY WILL REMAIN NEAR THE FREEZING MARK. THUS ANY RAIN THAT FALLS ONCE TEMPERATURES DROP TO THESE LEVELS MAY FREEZE ON ELEVATED OR EXPOSED SURFACES. HOWEVER...WITH PRE-EXISTING WARM GROUND TEMPERATURES...MINIMAL IMPACT IS EXPECTED ON ROAD SURFACES... EXCEPT PERHAPS ON EXPOSED BRIDGES AND OVERPASSES. NUISANCE ACCUMULATIONS CANNOT BE RULED OUT ON TREES AND POWERLINES...BUT ANY ICE THAT DOES ACCUMULATE IS EXPECTED TO REMAIN BELOW 1/4 INCH.
A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF SNOW...SLEET...OR FREEZING RAIN WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR SLIPPERY ROADS AND LIMITED VISIBILITIES...AND USE CAUTION WHILE
DRIVING.
$$
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
636 PM EST WED DEC 14 2005
.UPDATE...WITH WET BULB ZERO TEMPERATURES ALREADY BELOW FREEZING OVER A GOOD PORTION OF THE NORTH AND NORTHEAST...WOULD FEEL BETTER IF WE HAD MORE WIDESPREAD ADVISORIES OR WARNINGS FOR POSSIBLE FREEZING RAIN. MOST OF THE PRECIP STILL BACK IN ALABAMA...BUT 18Z NAM SHOWS PRECIP SPREADING QUICKLY INTO GEORGIA THIS EVENING. WITH NO SIGN OF ANY RISE IN DEW POINTS CURRENTLY...AS PRECIP BECOMES MORE STEADY SHOULD SEE A TEMPERATURE DROP...WHICH WOULD ONLY TAKE A FEW DEGREES TO REACH FREEZING SINCE MOST TEMPERATURES ALREADY IN THE MID 30S. WILL UPGRADE THE ADVISORY AREA TO AN ICE STORM WARNING AS THIS AREA SHOULD REACH FREEZING MORE QUICKLY AND HAVE LONGER DURATIONS. WILL PUT UP AN ADVISORY IN SOME COUNTIES OF NORTH AND NORTHEAST SURROUNDING THE WARNING AREA FOR SOME SLEET AND FREEZING RAIN...BUT WITH GROUND TEMPERATURES ABOVE FREEZING...ANY ACCUMULATION SHOULD BE IN TREES AND POWERLINES. HOWEVER DO NOT EXPECT ENOUGH DURATION IN THIS AREA TO CAUSE PROBLEMS.
URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
648 PM EST WED DEC 14 2005
...WINTER WEATHER POSSIBLE IN PARTS OF NORTHEAST GEORGIA...
.A WEDGE OF COLD DRY AIR HAS BUILT DOWN THE EASTERN SEABOARD... ALLOWING TEMPERATURES IN NORTHEAST GEORGIA TO HOVER JUST ABOVE FREEZING DURING THE EVENING. AS MOISTURE INCREASES FROM A STORM SYSTEM APPROACHING FROM THE WEST...PRECIPITATION MAY BEGIN THIS EVENING AS A WINTRY MIXTURE...AND CHANGE OVER TO RAIN OR FREEZING RAIN DURING THE OVERNIGHT AND EARLY THURSDAY MORNING HOURS.
GAZ014>016-022>024-150800-
/O.UPG.KFFC.WW.Y.0001.051215T0000Z-051215T1800Z/
/O.NEW.KFFC.IS.W.0001.051215T0000Z-051215T1800Z/
DAWSON-LUMPKIN-WHITE-FORSYTH-HALL-BANKS-
INCLUDING THE CITIES OF...DAHLONEGA...CLEVELAND...GAINESVILLE
648 PM EST WED DEC 14 2005
...ICE STORM WARNING IN EFFECT UNTIL 1 PM EST THURSDAY...
THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED AN ICE STORM WARNING...WHICH IS IN EFFECT UNTIL 1 PM EST THURSDAY. THE WINTER WEATHER ADVISORY IS NO LONGER IN EFFECT.
PRECIPITATION WILL BEGIN THIS EVENING LIKELY AS A PERIOD OF RAIN MIXED WITH LIGHT SLEET. ONCE TEMPERATURES BEGIN TO DROP...THEY WILL REMAIN NEAR THE FREEZING MARK. THUS ANY RAIN THAT FALLS ONCE TEMPERATURES DROP TO THESE LEVELS MAY FREEZE ON ELEVATED OR EXPOSED SURFACES. HOWEVER...AFTER MIDNIGHT TEMPERATURES MAY BE JUST BELOW FREEZING...ALLOWING ACCUMULATIONS OF ICE IN TREES...POWER LINES...AND BRIDGES AND OVER PASSESS.
AN ICE STORM WARNING MEANS SEVERE WINTER WEATHER CONDITIONS ARE EXPECTED OR OCCURRING. SIGNIFICANT AMOUNTS OF ICE ACCUMULATIONS WILL MAKE TRAVEL DIFFICULT. IF YOU MUST TRAVEL...KEEP AN EXTRA FLASHLIGHT...FOOD...AND WATER IN YOUR VEHICLE IN CASE OF AN EMERGENCY. ICE ACCUMULATIONS MAY LEAD TO SNAPPED POWER LINES AND FALLING TREE BRANCHES THAT ADD TO THE DANGER.
Steve Carpenter wrote:We're under all sorts of warnings and advisories - have cut & paste a brief synopsis of the NWS forecast discussion below. Has not gotten out of the upper 20's here today. I've lived in this area most of my life and have to say this has the makings of a classic ice storm from near NC/SC border in Tryon and continuing up the eastern slope of the Blue Ridge - so Tryon/Saluda>Lake Lure>Marion>Morganton>Lenoir>Mt. Airy. Winston Salem might get slammed. The higher elevations should be OK with inversion limiting icing time.
THE UPSHOT OF THIS IS THAT WE SHOULD SEE QPF AMOUNTS WELL OVER AN
INCH ACROSS THE HEART OF THE COLD AIR DAMMING REGION. COUPLE A
COLDER AND BETTER MAINTAINED LOW LEVEL AIRMASS WITH HEAVIER PCPN
RATES AND THE ICE STORM IS LOOKING MUCH MORE LIKELY AND POTENTIALLY
QUITE DAMAGING.
ONE CONCERN IS THAT THE MODELS ARE TAKING THE SFC LOW TOO FAR INTO
THE COLD AIR. IF THE LOW VERIFIES FARTHER SOUTH...AND IF THE HEAVY
RAINFALL DOESN/T BRING DOWN TOO MUCH WARM AIR...THEN DAMAGING ICE
ACCUMULATIONS COULD HAPPEN FARTHER SOUTH...INCLUDING IN THE
CHARLOTTE METRO AREA.
SHORT TERM FORECAST
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
726 PM EST WED DEC 14 2005
GAZ021>023-025-027-031>038-045>047-150200-
BARROW-CHEROKEE-CLARKE-COBB-DEKALB-FORSYTH-FULTON-GWINNETT-HALL- JACKSON-MADISON-OCONEE-OGLETHORPE-PAULDING-ROCKDALE-WALTON-
726 PM EST WED DEC 14 2005
.NOW...
AN AREA OF LIGHT RAIN MIXING WITH SLEET AND POSSIBLY FREEZING RAIN WILL CONTINUE THROUGH 9 PM OVER NORTHEAST GEORGIA. THIS AREA OF PRECIPITATION WILL AFFECT AREAS IN AND NEAR
ROSWELL...ATHENS...GAINESVILLE...CLEVELAND...AND DAHLONEGA DURING THE NEXT 90 MINUTES. MOTORISTS SHOULD SLOW DOWN AND USE CAUTION DUE TO SLICK ROADWAYS.
Tonight: Periods of rain possibly mixed with freezing rain and sleet. Low near 32. East wind between 10 and 15 mph. Chance of precipitation is 100%.
Thursday: Periods of rain possibly mixed with freezing rain before 1pm, then a chance of rain. High near 44. East wind between 5 and 15 mph. Chance of precipitation is 90%.
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