Winter Weather in Georgia, March 2, 2013

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
129 AM EST SAT MAR 2 2013

.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL MOVE EAST OVER TENNESSEE TONIGHT AND
ACROSS OUR REGION ON SATURDAY. HIGH PRESSURE BUILDS INTO THE AREA TO
START NEXT WEEK. THEN ANOTHER STORM SYSTEM SHOULD ARRIVE TUESDAY
INTO WEDNESDAY.

&&

.NEAR TERM /THROUGH TODAY/...
AS OF 105 AM...I HAVE UPDATED THE FORECAST THROUGH SATURDAY NIGHT.
THE UPDATE INCLUDES HIGHER FOOTHILL AND PIEDMONT POPS THIS MORNING
THROUGH THIS AFTERNOON. THE POTENTIAL EXIST FOR A BAND OF WEAKLY
CONVECTIVE SHOWERS TO DEVELOP ALONG THE EAST FACING SLOPES AROUND
18Z...THEN TRACK EAST THROUGH THE REST OF THE AFTERNOON.

2207 UTC UPDATE...POPS HAVE BEEN RAISED IN EXTREME NE GA AND THE
MOUNTAINS OF OCONEE AND PICKENS COUNTIES IN UPSTATE SC PER RADAR
TRENDS.

AT 900 PM EST FRIDAY...A MEAN EASTERN TROUGH REMAINED IN PLACE THIS
EVENING...WITH A SERIES OF WEAK UPPER LOWS OVER CAPE COD...KY AND
THE LOWER MS RIVER VALLEY...EACH WITH IT OWN TRAILING SHORTWAVE. LOW
LEVEL NW FLOW CONTINUED INTO THE NC MOUNTAINS...WHERE A FRESH BATCH
OF SNOW SHOWERS WAS ARRIVING FROM TN. THIS MOIST NW FLOW WILL
CONTINUE THROUGH SATURDAY...PRODUCING ACCUMULATIONS OF 2 TO 4
INCHES ALONG THEN TN BORDER. THE CURRENT WINTER WEATHER ADVISORY FOR
THAT AREA WILL REMAIN IN PLACE.

AS THE UPPER LOW NOW IN THE LOWER MS RIVER VALLEY MOVES NE INTO THE
TN VALLEY LATE TONIGHT...IT WILL DEEPEN SLIGHTLY...WHILE ITS
TRAILING SHORTWAVE REACHES N GA. THE UPPER LOW CROSSES THE
MOUNTAINS BY DAYBREAK...SPREADING PRECIPITATION EAST OF THE
MOUNTAINS...DESPITE A WEAK DOWNSLOPE COMPONENT AND ISENTROPIC
DOWNGLIDE. THIS LEE SIDE PRECIPITATION IS EXPECTED TO BE QUITE
LIGHT...BUT MODEL SOUNDINGS SUPPORT SNOW...AND LIGHT ACCUMULATIONS
WILL BE POSSIBLE IN UPPERMOST SAVANNAH RIVER VALLEY OF NE GA AND THE
SC MOUNTAINS. MINIMUM TEMPERATURES WILL RUN A CATEGORY OR TWO BELOW
NORMAL.

PRECIPITATION WILL CONTINUE TO SPREAD EAST INTO THE PIEDMONT ON
SATURDAY...INITIALLY AS SNOW...BUT WITH LOW LEVELS RAPIDLY
WARMING...WET BULB TEMPERATURES WILL SUPPORT A RAPID TRANSITION TO
RAIN SHOWERS BY MIDDAY. THE COMBINATIONS OF LIGHT QPF AND THE
TRANSITION TO LIQUID WILL LIMIT SNOWFALL ACCUMULATIONS EAST OF THE
MOUNTAINS TO A DUSTING OR LESS IN MOST LOCATIONS. BY LATE IN THE DAY
PRECIPITATION EAST OF THE MOUNTAINS WILL WIND DOWN...BRIEFLY
TRANSITIONING BACK TO SNOW IN THE PIEDMONT BEFORE EXITING OT THE
EAST. MODEL GUIDANCE WAS QUITE WARM WITH MAXIMUM TEMPERATURES
CONSIDERING THE DEPTH OF THE UPPER TROUGH...AND WITH PRECIPITATION
AND CLOUD COVER EXPECTED... FORECAST MAXIMUM TEMPERATURES WILL
UNDERCUT GUIDANCE BY SEVERAL CATEGORIES.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY/...
AS OF 2 PM EST FRI...THERE IS VERY GOOD AGREEMENT AMONGST THE
OPERATIONAL MODELS IN REGARD TO THE PLACEMENT AND STRENGTH OF THE
UPPER LOW AS IT MOVES ACROSS THE AREA ON SAT. MODELS FEATURE A 536
DM 500 MB LOW CENTER MOVING INTO THE NORTHERN UPSTATE SAT
MORNING...AND THEN EAST OF THE AREA BY EARLY AFTERNOON. THE UPPER
COLD POOL WILL PRODUCE ROBUST LAPSE RATES IN EXCESS OF 7 DEG C/KM UP
TO AROUND 700MB. HOWEVER...QG FORCING WITH THE SYSTEM IS NOT
ESPECIALLY STRONG OVER THE FORECAST AREA WHICH SHOULD LIMIT THE
AMOUNT OF PRECIP. THE GFS/ECMWF CONTINUE TO SUPPORT LIQUID
EQUIVALENT PRECIP AMOUNTS ON THE ORDER OF 0.05 TO 0.10 SAT...BUT THE
NAM AND SREF MEAN VALUES ARE LESS....THOUGH THE SREF HAS TRENDED A
BIT HIGHER WITH ITS MEAN QPF. HENCE...WILL CONTINUE TO ADVERTISE SCT
SHOWERS INTO MID AFTERNOON...BASICALLY DISSIPATING BY LATE SAT
AFTERNOON AS NVA AND A DRYER AIRMASS ARRIVE IN FORCE. PTYPE SAT
AFTERNOON WHERE SHOWERS OCCUR SHOULD BE A MIXTURE OF RAIN/SNOW. ANY
SNOW ACCUMULATIONS SHOULD BE TRACE TO NONE....BUT CAN'T RULE OUT A
QUICK COATING OF SNOW ON GRASSY AREAS WHERE THE STRONGEST CONVECTIVE
CELLS OCCUR.

THE BEFOREMENTIONED DRYER AIRMASS AND NVA WILL PRODUCE CLEARING
CONDITIONS OUTSIDE OF THE MOUNTAINS SAT EVENING. HOWEVER...
PERSISTENT LOW LEVEL NW FLOW AND LOW LEVEL MOISTURE WILL CONTINUE
NEAR THE IMMEDIATE TN BORDER THROUGH MOST OF SAT NIGHT. HOWEVER WITH
MOISTURE BECOMING MORE SHALLOW WITH TIME...SNOW SHOWERS WILL BECOME
MORE SCT WITH ONLY LIGHT ADDITIONAL ACCUMULATIONS...ENDING BY
BY SUNDAY MORNING. ABUNDANT SUNSHINE IS EXPECTED MOST AREAS ON SUNDAY
ALLOWING TEMPERATURES TO REBOUND AT LEAST A CATEGORY MOST LOCATIONS
DESPITE THE RATHER CHILLY THICKNESSES.

HIGH PRESSURE WILL CREST OVER THE REGION SUNDAY NIGHT ALLOWING FOR A
MOSTLY CLEAR AND COLD NIGHT ACROSS THE AREA WITH TEMPERATURES
DIPPING INTO THE TEENS IN MANY MOUNTAIN VALLEYS. CLOUDS WILL BE ON
THE INCREASE MONDAY AS THE HIGH PRESSURE RIDGE MOVES EAST OF THE
REGION. HIGH TEMPS ON MONDAY WILL BE TEMPERED BY THE INCREASING HIGH
LEVEL CLOUDS. EVEN WITH A SW FLOW WE ARE EXPECTING MAX TEMPS ONE TO
TWO CATEGORIES SHY OF NORMAL.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 305 PM FRI...CONFIDENCE CONTINUES TO INCREASE THAT A PRECIP
EVENT WILL TAKE PLACE MON NITE THRU TUE NITE. HOWEVER...UNCERTAINTY
REMAINS REGARDING TIMING AND ANY WINTRY PRECIP ACCUMS. THE ECMWF HAS
TRENDED TOWARD THE GFS REGARDING TIMING AND TRACK OF THE WX
SYSTEM...BUT REMAINS SLOWER TO MOVE IT EAST OF THE AREA. WHILE THE
CANADIAN IS FASTER AT ONSET BUT SIMILAR TO THE GFS AT THE END. THE
GFS IS THE WARMEST MODEL...THE CANADIAN IS SIGNIFICANTLY COLDER
WHILE THE ECMWF IS IN THE MIDDLE BUT TRENDING TOWARD THE GFS. THE
GEFS ENSEMBLE MEAN IS VERY CLOSE TO THE OPERATIONAL GFS...BUT A TAD
SLOWER ENDING THE PRECIP WED. THEREFORE...HAVE TRENDED TOWARD THE
GFS REGARDING ALL FACETS OF THE FCST...BUT PLAYED DOWN THE QPF
AMOUNTS AS IT IS SIGNIFICANTLY WETTER THAN ANY GUIDANCE.
THEREFORE...EXPECT PRECIP TO SPREAD INTO THE MTNS AFTER MIDNIGHT
MONDAY NITE...THEN SPREAD ACROSS THE CWFA DURING THE DAY. GUIDANCE
IS IN GOOD AGREEMENT WITH THIS AND EXPECTED PARTIAL THICKNESSES AND
FCST SOUNDINGS. WITH A SIGNIFICANT WARM NOSE DEVELOPING...PRECIP
WOULD BE RAIN...EXPECT ACROSS PORTIONS OF THE MTNS AND I-40 CORRIDOR
WHERE FREEZING RAIN DEVELOPS. THAT SAID...GUIDANCE LOWS HAVE RISEN
SIGNIFICANTLY...SO IT IS POSSIBLE THAT ANY FREEZING RAIN WOULD BE
MORE LIMITED IN COVERAGE. PRECIP QUICKLY BECOMES ALL LIQUID BY NOON.
THE GFS FCST SOUNDINGS SHOW WEAK INSTABILITY DEVELOPING DURING THE
AFTERNOON...SO ISOLATED TS COULD DEVELOP. AS THE LOW MOVES EAST OF
THE AREA TUE NITE...PRECIP SLOWLY MOVES EAST OF THE AREA WITH THE
ECMWF AND CANADIAN SHOWING LIGHT PRECIP CHANGING TO SNOW ACROSS NC
AND MIXING WITH SNOW ELSEWHERE. THE GFS HOWEVER...DEVELOPS
CONVECTIVELY ENHANCED PRECIP WITH A DEFORMATION ZONE...TROWAL AND
FRONTOGENESIS CENTERED ON THE NC/SC BORDER. SHOULD THIS DEVELOP...
AN AREA OF HEAVY SNOW WOULD BE EXPECTED. FOR NOW...HAVE KEPT PRECIP
GENERALLY LIGHT WITH SIGNIFICANT ACCUMULATIONS LIMITED TO THE NC
MTNS. END PRECIP FROM SW TO NE ACROSS THE CWFA WED A LITTLE SLOWER
THAN THE OPS GFS MORE IN LINE WITH THE GEFS MEAN. ANY LINGERING
AFTERNOON PRECIP WOULD CHANGE TO RAIN OUTSIDE OF THE MTNS WITH
LINGERING NW FLOW SNOW OVER THE NC MTNS ENDING WED NITE.

DRY FCST EXPECTED THU AND FRI WITH BELOW NORMAL TEMPS THU AND
APPROACHING NORMAL LEVELS FRI.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...THE 6Z TAF WILL BEGIN WITH VFR CONDITIONS AND A LIGHT NW
WIND. CEILING BASES SHOULD GRADUALLY LOWER THROUGH THE PRE DAWN
HOURS AS SYNOPTIC SCALE FORCING SPREADS ACROSS THE PIEDMONT. BY
12Z...MID LEVEL FORCING SHOULD PEAK ACROSS THE TERMINAL...THEN
WEAKENING THROUGH THE AFTERNOON HOURS. NAM FORECAST SOUNDINGS
SUPPORTS CEILINGS FALLING TO AT LEAST MVFR BY 12Z...THEN LIFTING
ABOVE 030 BY 22Z. THE ARRIVAL OF THE DEEP FORCING AT DAY BREAK MAY
YIELD ONE OF THE HIGHEST CHCS FOR PRECIP DURING THE PERIOD. I WILL
HIGHLIGHT -SHSN BETWEEN 12Z TO 15Z. ANOTHER BAND OF RASN MAY PASS
ACROSS THE TERMINAL BETWEEN 22Z TO 24Z WITH THE PUSH OF THE DRY
SLOT. ONCE THE DRY SLOT ARRIVES...CEILINGS WILL LIFT AND STEADY NW
WINDS SHOULD REMAIN THROUGH 12Z SUN. I WOULD EXPECT THAT
ACCUMULATING SNOW IS POSSIBLE THIS MORNING AND AGAIN LATE THIS
AFTERNOON...ACCUMS WILL LIKELY REMAIN LESS THAN A HALF INCH.

ELSEWHERE...TIMING SIMILAR TO CLT. HOWEVER...KGSP...KGMU...AND KHKY
SHOULD SEE MVFR CEILINGS DEVELOP AROUND 11Z...BUT DOWNSLOPE FLOW
SHOULD SUPPORT VFR BY MID MORNING. ALL AREAS WILL SEE THE POTENTIAL
FOR LIGHT ACCUMULATING SNOW THIS MORNING....BEST CHC BETWEEN 12Z TO
16Z. HOWEVER...THE FORMATION OF A WEAKLY CONVECTIVE BAND THIS
AFTERNOON WILL NEED CLOSE ATTENTION.

OUTLOOK...SNOW SHOWERS WILL DIMINSIHING THE TENNESSEE BORDER ON
SUNDAY. MONDAY SHOULD REMAIN VFR ACROSS THE FORECAST AREA.
ANOTHER LOW PRESSURE SYSTEM WILL SPREAD LLVL MOISTURE AND
PRECIPITATION ACROSS THE REGION TUESDAY AND WEDNESDAY MORNING.

CONFIDENCE TABLE...

            06-12Z        12-18Z        18-24Z        00-06Z
KCLT       HIGH 100%     MED   73%     MED   77%     HIGH 100%
KGSP       HIGH  96%     HIGH  83%     HIGH  92%     HIGH 100%
KAVL       HIGH  84%     HIGH  89%     HIGH  99%     HIGH 100%
KHKY       HIGH 100%     MED   76%     HIGH  99%     HIGH 100%
KGMU       HIGH  94%     MED   73%     HIGH  81%     HIGH 100%
KAND       HIGH  84%     MED   75%     HIGH  92%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ033-
     048>052-058-059.
SC...NONE.

&&

SYNOPSIS...ARK
NEAR TERM...NED
SHORT TERM...LG
LONG TERM...RWH
AVIATION...NED

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
452 PM EST FRI MAR 1 2013

NCZ033-048>052-058-059-022200-
AVERY-MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-GRAHAM-NORTHERN JACKSON-
452 PM EST FRI MAR 1 2013

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 PM EST SATURDAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN NORTH CAROLINA.

.DAY ONE...TONIGHT.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   WINTER WEATHER ADVISORY.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   WINTER WEATHER ADVISORY.

A LOW PRESSURE SYSTEM MOVING ACROSS THE AREA TUESDAY INTO
WEDNESDAY WILL BRING WIDESPREAD PRECIPITATION TO THE AREA. THE
PRECIPITATION COULD BEGIN AS FREEZING RAIN IN THE MOUNTAINS MONDAY
NIGHT. RAIN IS EXPECTED TUESDAY WHICH COULD CHANGE TO SNOW TUESDAY
NIGHT INTO WEDNESDAY. A HEAVY ACCUMULATING SNOW CANNOT BE RULED
OUT.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SNOW AND ICE ACCUMULATIONS
TO THE NATIONAL WEATHER SERVICE.

GAZ010-017-018-026-028-029-NCZ035>037-053-056-057-062>065-068>072-
082-501>510-SCZ001>014-019-022200-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-HART-ELBERT-ALEXANDER-IREDELL-
DAVIE-BUNCOMBE-CATAWBA-ROWAN-MACON-SOUTHERN JACKSON-TRANSYLVANIA-
HENDERSON-CLEVELAND-LINCOLN-GASTON-MECKLENBURG-CABARRUS-UNION NC-
CALDWELL MOUNTAINS-GREATER CALDWELL-BURKE MOUNTAINS-GREATER BURKE-
MCDOWELL MOUNTAINS-EASTERN MCDOWELL-RUTHERFORD MOUNTAINS-
GREATER RUTHERFORD-POLK MOUNTAINS-EASTERN POLK-OCONEE MOUNTAINS-
PICKENS MOUNTAINS-GREENVILLE MOUNTAINS-GREATER OCONEE-
GREATER PICKENS-GREATER GREENVILLE-SPARTANBURG-CHEROKEE-YORK-
ANDERSON-ABBEVILLE-LAURENS-UNION SC-CHESTER-GREENWOOD-
452 PM EST FRI MAR 1 2013

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

.DAY ONE...TONIGHT.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

AN UPPER LEVEL LOW PRESSURE SYSTEM IS EXPECTED TO CROSS THE
WESTERN CAROLINAS AND NORTHEAST GEORGIA ON SATURDAY. THIS SYSTEM
WILL LIKELY SUPPORT SCATTERED TO NUMEROUS RAIN OR SNOW SHOWERS AS
IT CROSSES THE REGION. ALTHOUGH TEMPERATURES ARE EXPECTED TO BE
COOL ENOUGH TO SUPPORT SNOW AT TIMES...THE BEST CHANCE OF
ACCUMULATING SNOW WILL BE IN THE HIGHER TERRAIN OF THE
MOUNTAINS. ANY HEAVIER EMBEDDED SHOWERS...HOWEVER...COULD PRODUCE
LIGHT SNOW ACCUMULATIONS IN THE FOOTHILLS AND PIEDMONT AS WELL.
MAINLY A DUSTING OF SNOW WOULD BE POSSIBLE IN THESE AREAS...BUT A
QUICK COATING UP TO AN INCH CANNOT BE RULED OUT IN ANY HEAVIER
SNOW SHOWERS.

ANOTHER LOW PRESSURE SYSTEM MOVING ACROSS THE AREA TUESDAY INTO
WEDNESDAY WILL BRING WIDESPREAD PRECIPITATION TO THE AREA. RAIN
IS EXPECTED TUESDAY WHICH COULD CHANGE TO SNOW TUESDAY NIGHT INTO
WEDNESDAY. ACCUMULATING SNOW CANNOT BE RULED OUT.

.SPOTTER INFORMATION STATEMENT...

NONE.