Winter Storm in Georgia, January 29, 2005

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1047 AM EST SAT JAN 29 2005

.SHORT TERM (REST OF TODAY)...
WINTER STORM WARNING REMAINS IN EFFECT THROUGH 6 AM SUNDAY FOR ALL
ZONES.

LATE MORNING CALLS TO COUNTIES IS INDICATING AN EXTREMELY VARIED MIX
OF PRECIPITATION TYPES...ACCUMULATIONS AND INTENSITIES. SNOW ACCUMS
IN THE MOUNTAINS ARE ABOUT ON TRACK...BUT AS PRECIP INTENSITIES
HAVE DECREASED ACROSS THE UPSTATE AND NE GEORGIA IT HAS CHANGED OVER
TO FREEZING RAIN/DRIZZLE AND SLEET. WAVES OF PRECIPITATION ARE
FORMING IN HIGH THETA-E REGION OVER CENTRAL GEORGIA ATTM AND
SPREADING NE ACROSS OUR AREA. LATEST RUN OF NAM-12 AND GFS SHOW
THIS AXIS OF HIGHER MOISTURE AND FORCING SHIFTING EAST THROUGH THE
DAY TODAY...SO WAVES OF HIGHER RETURNS SHOULD BECOME MORE FREQUENT
AS THE AFTERNOON PROGRESSES. WILL TRY TO MENTION OCCASIONAL WORDING
IN ZONES.

P-TYPE SWITCHES ARE FREQUENT EVEN HERE AT GSP TODAY. THIS MAKES IT
NEARLY IMPOSSIBLE TO TIME EACH AREA FOR PRECIP TYPE THROUGH THE
AFTERNOON. WARM NOSE ALOFT STILL PROGGED TO INCREASE THROUGH THE
AFTERNOON...WITH A CHANGEOVER TO ZR AND PL MID-LATE AFTERNOON
OUTSIDE THE MOUNTAINS. OUR EXTREME WRN NC MTN ZONES HAVE ALREADY FOR
THE MOST PART WARMED ABOVE FREEZING AT THE SFC. THESE AREAS WILL
PROBABLY NOT SEE WARNING CRITERIA ACCUMS TIL TONIGHT WHEN UPPER LOW
COOLS THE COLUMN AND PROVIDES SOME FRONTOGENETICAL FORCING. TOTAL
SNOW ACCUM FORECAST OVER MOUNTAINS STILL SEEMS LOGICAL. WILL LOWER
SNOW AMOUNTS OVER THE UPSTATE FOR TODAY B/C PRECIP HAS FALLEN AS MORE
ZR AND PL THAN PREVIOUSLY EXPECTED. AS HINTED AT FROM COUNTY
CANVAS THIS MORNING...ACCUMULATIONS ARE GOING TO VARY WILDLY EVEN
THIS AFTERNOON ACROSS THE PIEDMONT AND FOOTHILLS. WILL TRY TO HAVE
UPDATED ZONES OUT BY NOON. STAY TUNED FOR PUBLIC INFO STATEMENTS
WITH LATEST INFORMATION FROM COUNTIES AND SPOTTERS.
&&

.PREVIOUS DISCUSSION...
THE FOLLOWING WAS ORIGINALLY ISSUED AT 538 AM EST SAT JAN 29 2005

SHORT TERM (REST OF TODAY)...
HAVE TWEAKED THE ZONES A LITTLE TO BRING HEAVIER ICE ACCUMULATIONS A
LITTLE FARTHER NORTH INTO THE UPSTATE AND NORTHEAST GEORGIA. 0600
UTC MODELS WERE JUST A HAIR WARMER OVER THE SRN HALF OF THE CWFA.
HOWEVER...PREVIOUS THINKING STILL HOLDS...AND NO OTHER CHANGES MADE
AT THIS TIME.

THE FOLLOWING WAS ORIGINALLY ISSUED AT 301 AM EST SAT JAN 29 2005

SHORT TERM (TODAY THROUGH SATURDAY NIGHT)...

WINTER STORM WARNING CONTINUES FOR THE ENTIRE CWFA TDA AND TNGT.

THE COLDER TREND IN THE MAV AND THE NAM HAS CONTINUED OVER THE PAST
24 HRS. THIS IS CERTAINLY A GOOD EXAMPLE OF AN OUTLIER EVENT THAT
THE MODELS TOOK QUITE A WHILE TO FULLY CAPTURE. MOS HIGHS ON THE MAV
AND MET DON/T GET OUT OF THE 20S ACROSS MOST OF THE CWFA TODAY WITH
ONLY VERY SLOW RECOVERY TNGT...AND MODEL SOUNDINGS ARE EXHIBITING
DEEP...NEAR-FREEZING ISOTHERMAL LAYERS THAT PORTEND MULTIPLE INCH
PER-HOUR SNOWFALL RATES BEFORE TRANSITION TO OTHER P-TYPES.

LOOKING AT THE ETA 700 MB MIXING RATIOS ADVECTING INTO THE
REGION...AND CONSIDERING THE 12 HR PERIOD OF GOOD UVVS...THIS WOULD
YIELD AT LEAST 4 TO 8 INCHES OF SNOW TODAY WHERE PCPN STAYS ALL SNOW
USING A SORT OF POOR MANS GARCIA METHOD. THIS LINES UP FAIRLY WELL
WITH THE ETA AND GFS SNOW ALGORITHMS AS WELL AS THE INTERNAL
COORDINATION GRAPHICS FROM HPC. THE CENTRAL AND NRN NC MTNS...THE
NC FOOTHILLS AND THE NRN REACHES OF THE PIEDMONT LOOK LIKE THEY WL
STAY SNOW ALL DAY. IN THE TRANSITION ZONE IS WHERE THINGS GET
TRICKY. WE COULD BE DEALING WITH 8+ INCHES OF HEAVY SNOW...OR WE
COULD BE DEALING WITH AN INCH OF SLEET. THEREFORE... ROUGHLY ALONG
AND NORTH OF A LINE FROM GSP TO CLT TO HAVE 4+ INCH SNOWFALL
AMOUNTS...WITH A LATE DAY TRANSITION TO SLEET. HAVE GONE 8+ INCHES
JUST N OF AN HKY TO AVL LINE. MODEL SOUNDINGS IMPLY THAT THE BEST
CHANCE OF FREEZING RAIN WL BE CONFINED TO THE SE MOST PART OF THE
CWFA IN THE AFTN...AND POSSIBLY IN THE INTERIOR VALLEYS OF THE SW
MTNS.

LOOKING AT THE LARGE AREA OF COLD CLOUD TOPS BLOSSOMING OVER AL AND
GA...AND CONSIDERING THE FAIRLY WEAK SFC FEATURES...CERTAINLY GIVES
ONE PAUSE. IN PARTICULAR...THERE COULD BE QUITE A BIT OF
CONVECTIVELY INDUCED COOLING WHICH PUTS THE BREAKS ON OUR ALREADY
WEAKER LOOKING WARM NOSE. THROW IN CONVECTIVELY AUGMENTED SNOWFALL
RATES...AND A FOOT OF SNOW WOULD NOT BE OUT OF THE QUESTION ALONG
AND N OF I-85. WE WL WATCH THIS TREND VERY CAREFULLY. WL CERTAINLY
MAKE SURE TO INCLUDE HEAVY SNOW WORDING IN THE ZONES.

ALL OF THIS IS PRIMARILY WITH THE WARM CONVEYOR BELT PCPN TDA.
THE NEXT PROBLEM WL BE TNGT AS THE H5 LOW ROLLS ACROSS THE CWFA.
WHILE THE ETA AND GFS ARE IN REASONABLY GOOD AGREEMENT WITH THEIR
THICKNESSES AND P-TYPE TDA...THINGS CHANGE A BIT AS THE UPPER LOW
APPROACHES. THE GFS IS COLDER AND HAS A DEFORMATION ZONE OVER THE
NRN MTNS AND THE NRN FOOTHILLS. LAPSE RATES ARE STEEP THROUGH THE
PERIOD...BUT THEY REALLY STEEPEN THIS EVENING. IT IS LIKELY THAT
ADDITIONAL CONVECTIVE ELEMENTS WL DEVELOP IN AREA OF PVA IMMEDIATELY
AHEAD OF THE VORT. THIS COULD REST IN FURTHER HEAVY SNOW FROM THE
NRN MTNS INTO THE NRN FOOTHILLS AND PIEDMONT...AND OTHER HEAVY
P-TYPES FARTHER S. CONSIDERING THE REMARKABLE CONSISTENCY OF THE
GFS...WL FOLLOW IT/S THICKNESSES AND MODEL SOUNDINGS CLOSELY...WHICH
MEANS KEEPING HEAVY SN/IP IN THE NRN TIER AT LEAST THROUGH 0600 UTC.
WE MAY ALSO SEE SOME OF THE BEST FRZA IN THE SRN TIER OF ZONES THIS
EVENING AS THE WARM NOSE IS PROGGED TO SPREAD ACROSS THE SRN UPSTATE
AND EXTREME SRN NC PIEDMONT. A QUARTER INCH OR MORE OF ICE APPEARS
LIKELY FROM MONROE TO CHESTER...ABBEVILLE AND GREENWOOD...WITH A
REASONABLE CHANCE FROM AND TO GSP AND CLT.

LONG TERM (SUNDAY THROUGH FRIDAY)...
MOSTLY COSMETIC CHANGES MADE TO THE OTHER PERIODS OF THIS
FORECAST...BUT ONE BIG CHANGE EARLY WAS EXTENSION OF FREEZING
RAIN/SNOW INTO THE EARLY SUNDAY MORNING PERIOD...WITH BOTH GFS AND
NAM KEEPING ABUNDANT LOW LEVEL MOISTURE OVER THE REGION. MODELS
TRENDING TO BRINGING 85H LOW OVER THE MOUNTAINS...AND EVENTUALLY
SOUTH...RESULTING IN A PERIOD OF WEAK UPSLOPE INTO HIGHER TERRAIN
LOCATIONS EARLY SUNDAY. TEMPERATURES LOOK TO STILL BE AROUND
FREEZING. MOISTURE PROFILE LOOKS SUFFICIENT TO SUPPORT RESIDUAL
FREEZING DRIZZLE/FREEZING RAIN SOUTH. PRECIPITATION WAS ENDED FOR
GOOD WITH THIS EVENT LATE SUNDAY MORNING.

TEMPERATURES WERE TRENDED GENERALLY DOWNWARD FOR DAYS THREE AND
FOUR...GIVEN EXPECTED SNOW COVER AND RESIDUAL CLOUDINESS THAT MAY
KEEP TEMPERATURES DOWN. MAXES NEAR NORMAL FOR THIS TIME OF YEAR
ADVERTISED BY TUESDAY FOR NORTHEAST GEORGIA AND THE SOUTHERN
UPSTATE.

NO OTHER CHANGES WERE MADE TO THE EXTENDED PORTION OF THE
FORECAST...BUT MUCH UNCERTAINTY REMAINS WITH THE VARIOUS MEDIUM
RANGE ENSEMBLES OFFERING A PLETHORA OF SOLUTIONS TO WEATHER OVER OUR
REGION THROUGH LATE WEEK AND INTO NEXT WEEKEND.

AVIATION...
YET ANOTHER COLDER RUN OF THE MODELS...SUPPORTING EVEN LONGER
DURATION OF SNOW AND SLEET...WITH AN EVEN LATER TRANSITION TO
FREEZING RAIN AT TAF SITE. WILL DELAY CHANGEOVER UNTIL EARLY
EVENING...ESPECIALLY NC SITES. FIRST ROUND OF PRONOUNCED LIFT NOW
EARLY IN MORNING BEFORE DEEP MOISTURE IN PLACE...AND WILL BACK OF ON
TEMPO IFR VSBYS IN MORNING. BELIEVE ISENTROPIC LIFT STILL SUPPORTS
IFR CIGS EARLY.

ONCE FZRA BECOMES ESTABLISHED...IT SHOULD RAPIDLY BECOME
PREDOMINANT. BEST LIFT IS CLEARLY DURING THE 22-06Z TIME FRAME...AND
THAT IS WHEN LOWEST VSBY/CIG WILL BE CARRIED...WITH LIFR CONITIONS
IN HEAVIER PRECIPITATION BURSTS. SOME CONCERN FOR CONVECTION AFTER
03Z AS WARM NOSE STEEPENS ELEVATED LAPSE RATES...BUT WILL NOT CARRY
THUNDER FOR NOW AS COOLING TREND IN MODEL RUNS MAY BELAY
DESTABILIZATION.
&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...WINTER STORM WARNING FOR ZONES GAZ010-017-018-026-028-029
    THROUGH TONIGHT.
NC...WINTER STORM WARNING FOR ZONES NCZ033>035-037-038-048>059-
     062>072-082 THROUGH TONIGHT.
SC...WINTER STORM WARNING FOR ZONES SCZ001>014-019 THROUGH TONIGHT.
&&

SHORT TERM (UPDATE)...LAMB

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
554 AM EST SAT JAN 29 2005

GAZ010-017-018-026-028-029-NCZ033>037-048>059-062>072-082-SCZ001>014-
019-301053-
ABBEVILLE SC-ALEXANDER NC-ANDERSON SC-AVERY NC-BUNCOMBE NC-BURKE NC-
CABARRUS NC-CALDWELL NC-CATAWBA NC-CHEROKEE SC-CHESTER SC-
CLEVELAND NC-DAVIE NC-ELBERT GA-FRANKLIN GA-GASTON NC-GRAHAM NC-
GREATER GREENVILLE SC-GREATER OCONEE SC-GREATER PICKENS SC-
GREENVILLE MOUNTAINS SC-GREENWOOD SC-HABERSHAM GA-HART GA-HAYWOOD NC-
HENDERSON NC-IREDELL NC-LAURENS SC-LINCOLN NC-MACON NC-MADISON NC-
MCDOWELL NC-MECKLENBURG NC-MITCHELL NC-NORTHERN JACKSON NC-
OCONEE MOUNTAINS SC-PICKENS MOUNTAINS SC-POLK NC-RABUN GA-ROWAN NC-
RUTHERFORD NC-SOUTHERN JACKSON NC-SPARTANBURG SC-STEPHENS GA-
SWAIN NC-TRANSYLVANIA NC-UNION SC-UNION NC-YANCEY NC-YORK SC-
554 AM EST SAT JAN 29 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN NORTH CAROLINA...
UPSTATE SOUTH CAROLINA...AND EXTREME NORTHEAST GEORGIA.

.DAY ONE...
A WINTER STORM WARNING IS IN EFFECT THROUGH TONIGHT FOR ALL OF THE
WESTERN CAROLINAS AND NORTHEAST GEORGIA. HEAVY SNOW AND SLEET WILL
DEVELOP OVER THE REGION THIS MORNING. OVER THE UPSTATE AND NORTHEAST
GEORGIA THE PRECIPITATION WILL MIX WITH FREEZING RAIN IN THE
AFTERNOON...WHILE OVER MOST OF NORTH CAROLINA MOSTLY SNOW AND SLEET
IS EXPECTED. BY THIS EVENING...SEVERAL INCHES OF SNOW ARE EXPECTED
ALONG AND NORTH OF INTERSTATE 85...WITH DAMAGING ICE ACCUMULATIONS
EXPECTED SOUTH OF THIS LINE. FREEZING RAIN WILL AFFECT A LARGER PART
OF THE UPSTATE AND THE NORTH CAROLINA PIEDMONT THIS EVENING...WITH
DAMAGING ICE ACCUMULATIONS SPREADING THROUGH THE GREENVILLE...
SPARTANBURG AND CHARLOTTE METRO AREAS. PRECIPITATION WILL TAPER OFF
TO FREEZING DRIZZLE BY SUNDAY MORNING. ROADS WILL BE IMPASSABLE IN
MUCH OF THE AREA TODAY AND TONIGHT AND WIDESPREAD POWER OUTAGES ARE
QUITE LIKELY WHERE THE FREEZING RAIN IS HEAVIEST. SEE OUR LATEST
WINTER STORM WARNING /CAEWSWGSP/ FOR MORE SPECIFIC INFORMATION.

.DAYS TWO THROUGH SEVEN...

FREEZING DRIZZLE WILL BE POSSIBLE OVER MUCH OF THE AREA SUNDAY
MORNING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE LIKELY.