Winter Weather in Georgia, December 12, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
858 PM EST SAT DEC 11 2010

.SYNOPSIS...
HIGH PRESSURE WILL SHIFT EAST OVERNIGHT ALLOWING A COLD FRONT TO
PUSH THROUGH THE AREA. COLDER AIR WILL RUSH IN BEHIND THE FRONT
RESULTING IN COLDER THAN NORMAL TEMPERATURES WHICH WILL REMAIN
THROUGH THE MIDDLE OF NEXT WEEK. ANOTHER FRONT WILL APPROACH THE
AREA FROM THE SOUTH ON THURSDAY.

&&

.NEAR TERM /THROUGH SUNDAY/...
A CLOSED UPPER LOW IN THE MIDWEST WILL DIVE INTO THE LOWER OH VALLEY
TONIGHT...WHILE A COLD FRONT MOVES FROM THE TN AND OH VALLEYS... AND
INTO THE MOUNTAINS. WINDS AT 850 MB APPROACH 40 KNOTS...AND WINDS
HAVE BEEN INCREASED IN THE FORECAST. WIND ADVISORY CRITERIA WILL
ONLY BE REACHED ON A FEW PEAKS IN THE SMOKY MOUNTAINS AND SNOWBIRD
MOUNTAINS. LAKE WIND ADVISORY CRITERIA ARE NOT EXPECTED AT
ELEVATIONS AS LOW AS LAKES IN THAT AREA. LIGHT RAINFALL IN
ISENTROPIC UPGLIDE HAS SPREAD WEST INTO THE PIEDMONT COUNTIES...
WHERE POPS WILL BE INCREASED THIS EVENING. POPS WILL ALSO BE
INCREASED IN THE MOUNTAINS...AS RAINFALL IN TN IS MAKING GOOD
PROGRESS EAST. MODEL SOUNDING ARE SUPPORTIVE OF A MIX OF SNOW AND
SLEET IN THE MOUNTAINS...WITH A FEW POCKETS OF FREEZING RAIN. AREAS
EAST OF THE MOUNTAINS WILL SEE RAIN. INSTABILITY IS EXPECTED TO BE
INSUFFICIENT FOR A MENTION OF THUNDERSTORMS. THE LATEST FORECAST
SNOWFALL AMOUNTS FALL JUST SHY OF WINTER STORM CRITERIA AT HIGH
ELEVATIONS...AND THE WINTER WEATHER ADVISORY WILL BE CONTINUED
THERE. CLOUDS WILL LIMIT COOLING OVERNIGHT.

STRONG SYNOPTIC FORCING WILL MOVE ACROSS THE FORECAST AREA FROM WEST
TO SUNDAY MORNING PRODUCING A SEVERAL HOUR WINDOW OF MODERATE
PRECIP. PRECIP ENDS QUICKLY SUNDAY AFTERNOON AS DRY SLOT DEVELOPS.
THERE WILL LIKELY BE A LULL IN PRECIP IN THE MOUNTAINS FOR SEVERAL
HOURS...BEFORE PICKING BACK UP IN TN BORDER COUNTIES SUN
AFTERNOON AS STRONG NW WIND/COLD ADVECTION KICKS IN AND UPPER
TROUGH APPROACHES. SOME SNOW SHOWERS WILL LIKELY BREAK CONTAINMENT
INTO THE FOOTHILLS AND NE GA LATE SUN AFTERNOON...BUT EXPECT LITTLE
IF ANY ACCUMS. WEST FACING SLOPES OF RABUN/HABERSHAM COUNTIES COULD
SEE A DUSTING LATE SUN AFTERNOON.

WILL CONTINUE WINTER STORM WARNING FOR THE MOUNTAINS BEGINNING
SUNDAY AFTERNOON EXTENDING THROUGH MON FOR ELEVATIONS >3500FT IN THE
FAVORED NW FLOW MOUNTAIN COUNTIES WITH ADVISORIES BELOW. SEE SHORT
TERM DISCUSSION FOR THE VARIOUS HAZARDS/SNOW ACCUMS EXPECTED DURING
THAT PERIOD.

USED A BLEND OF GMOS/NAM FOR NON-DIURNAL TEMPS ON SUN. TEMPS
EXPECTED TO PLUMMET LATE SUN AFTERNOON AS ARCTIC AIR ARRIVES.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
AS OF 2 PM SATURDAY...THE SHORT TERM FCST PICKS UP AT 00Z ON MONDAY
WITH THE DEEP UPPER LVL TROF AXIS ORIENTED NORTH/SOUTH OVER FAR
WESTERN NC/SC. OVER THE NEXT 48 HRS THE SOUTHERN MOST STREAM OF
ENERGY WILL ROTATE OVER FLORIDA AND THEN OUT OVER THE ATLANTIC
GIVING THE TROF AN OVERALL NEGATIVE TILT BY 00Z TUES. IT WILL
CONTINUE TO LIFT NE OVER NEW ENGLAND AS AN AREA OF BROAD H5 NW FLOW
BUILDS IN BEHIND THE SYSTEM AND THE OVERALL SYNOPTIC PATTERN
DEAMPLIFIES. THE LATEST 12Z GFS RUN CONTINUES TO TRANSLATE THE UPPER
TROF AWAY FROM THE CAROLINAS FASTER THAN THE OLDER 00Z ECMWF...WHICH
TRIES TO CLOSE OFF SOME SORT OF H5 LOW ON WED. THE GFS IS MORE IN
LINE WITH THE GEM AND NAM SOLUTIONS...AND SREF FOR THAT MATTER...SO
I THINK ITS SOLUTION IS MORE SOUND. AT THE SFC...THE COLD FRONT
SHOULD BE MOVING OFFSHORE BY LATE SUNDAY EVENING AS THE LOW LVL DRY
SLOT MOVES OVER THE AREA. ONCE MY PERIOD BEGINS...NW FLOW SNOW
CONDITIONS QUICKLY SET UP AND I EXPECT SNOW ACCUMULATIONS EARLY ON
OVER THE NC MOUNTAINS. MODELS CONTINUE TO SHOW GOOD H850 MOISTURE
TRANSPORT...VERY STRONG NWLY FLOW...AND VERY COLD THICKNESSES FROM
THE START OF THE PERIOD THRU EARLY TUES. WITH THESE FACTORS IN
PLACE...WE DECIDED TO ISSUE A WINTER STORM WRN FOR ELEVATIONS ABOVE
3500FT IN THE NC MTS AND AN ADVISORY BELOW 3500FT FOR SNOWFALL
ACCUMS...ADVISORY LEVEL WINDS AND WIND CHILLS. RIGHT NOW THE HIGHEST
STORM TOTAL SNOW I HAVE IN THE GRIDS IS AROUND 7 INCHES...HOWEVER
THE HIGHEST ELEVATIONS COULD EASILY SEE MORE SNOWFALL IF THEIR SNOW
TO LIQUID RATIOS EXCEED THE VALUES I USED...IE...AROUND 16 TO 1.
SNOWFALL SHOULD WIND DOWN LATE TUESDAY MORNING/AFTERNOON AS LOW LVLS
DRY OUT AND THE CENTER OF THE SFC HIGH GRADUALLY SLIDES EASTWARD
TOWARD OUR AREA AND WINDS RELAX. DONT HAVE ANY SIG POPS AFTER 18Z TUES.
TEMPS WILL BE WELL BELOW NORMAL WITH HIGHS ON MON AND TUES IN THE
LOW TO MID 30S OVER THE PIEDMONT/FOOTHILLS AND LOW TO MID 20S IN THE
MTS. LOWS MON AND TUES NIGHT WILL RANGE FROM THE MID TO UPPER TEENS
TO THE LOW TEENS HIGH SINGLE DIGITS FOR THE LOWER/HIGHER ELEVATIONS
RESPECTIVELY.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 245 PM SATURDAY...MEANWHILE...OUT IN THE MEDIUM RANGE...FLYING
UNDER THE RADAR WHILE MOST OF THE ATTENTION IS GIVEN TO THE NEAR
TERM STORM...THERE REMAINS A PESKY WEAK SYSTEM MOVING QUICKLY ACROSS
THE SRN PLAINS/SOUTHEASTERN U.S. TOWARD THE END OF THE WEEK. THE
PROBLEM IS TIMING OF THE WEAK WAVE...WHICH IS ALWAYS DIFFICULT IN
THESE SITUATIONS WHEN SOMETHING COMES RIPPING ALONG IN THE SRN PART
OF THE STREAM. THE GFS CONTINUES TO BE THE FASTEST WITH BRINGING
MOISTURE BACK LATE IN THE DAY ON WEDNESDAY...WHILE THE ECMWF IS
ABOUT 12-24 HOURS SLOWER. WILL CONTINUE TO LEVERAGE THE EXPERTISE
AND GUIDANCE FROM HPC ON THIS ONE BECAUSE THEY GET TO LOOK AT THE
ECMWF ENSEMBLE. THE HPC GUIDANCE HAS A WEAK SURFACE LOW MOVING FROM
THE OZARKS THURSDAY MORNING TO THE COASTAL PLAIN ON FRIDAY
MORNING...RIDING ALONG A WEAK FRONT. FOLLOWING THIS SCENARIO...
MOISTURE WOULD BEGIN TO SPREAD BACK FROM THE SW WEDNESDAY NIGHT
ALONG WITH ISENTROPIC UPGLIDE AND SOME WEAK UPPER DIVERGENCE. THE
PROBLEM IS THAT WE HAVE A COLD WEAK HIGH TO OUR N AND NE EARLY
THURSDAY MORNING WHICH WILL ALLOW TEMPS TO BE BELOW FREEZING NEAR
THE SURFACE WHILE WARM AIR SLIDES IN ALOFT. IT SEEMS LIKE EVERY
WINTER WE GET AT LEAST ONE OF THESE NUISANCE EVENTS WITH LOW PRECIP
AMOUNTS BUT COLD TEMPS THAT RESULT IN A LOW END FREEZING RAIN
THREAT...SO WE WILL GO WITH THAT WEDNESDAY NIGHT AND THURSDAY
MORNING. AT THIS POINT...I CANNOT STRESS ENOUGH ABOUT THE
UNCERTAINTY WITH THE PATTERN AND TIMING. THE POP IS LOW ENOUGH THAT
WE COULD TURN THE WHOLE THING AROUND AND SAY THAT IT IS LIKELY THAT
NOTHING SIGNIFICANT WILL HAPPEN. NEVERTHELESS...THERE WILL BE A
20/30 PCT CHANCE OF SOME FREEZING RAIN BEFORE SUNRISE ON THURSDAY.
THE WEAK SYSTEM MOVES ACROSS THE REGION EARLY FRIDAY SO WE SHOULD
STAY WARM ENOUGH AT ALL BUT THE HIGHEST ELEVATIONS THURSDAY NIGHT TO
KEEP ANY PRECIP LIQUID. BEHIND THE LOW...WE TRANSITION TO ANOTHER
VERY LOW END NW FLOW SNOW SITUATION FRIDAY NIGHT AND SATURDAY BEFORE
THE MOISTURE PULLS OUT. LOOKING FARTHER AHEAD...IT LOOKS LIKE WE
WILL EVENTUALLY SLIP BACK INTO THE COLD PATTERN OVER THE NEXT
WEEKEND.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
AT KCLT...ISENTROPIC UPGLIDE IS EXPECTED TO MAINTAIN AN MVFR CEILING
OVERNIGHT...LOWERING BELOW 2K FT BY LATE EVENING. GUIDANCE IS
GENERALLY IN AGREEMENT ON A LIFR CEILING BY MORNING AS LOW LEVEL
MOISTURE INCREASED IN SOUTHERLY FLOW AHEAD OF AN APPROACHING FRONT.
THE BEST CHANCE OF PRECIPITATION WILL BE SUNDAY BETWEEN DAWN AND
MIDDAY...WHEN MVFR VISIBILITY IS EXPECTED. VFR CAN BE EXPECTED TO
RETURN IN THE AFTERNOON WITH FRONTAL PASSAGE...AS WINDS INCREASE
FORM THE SOUTHWEST.

ELSEWHERE...MVFR CEILING WILL SPREAD WEST FROM THE PIEDMONT INTO THE
FOOTHILLS AFTER MIDNIGHT. CEILINGS WILL LOWER FURTHER TO LIFR BY
DAWN IN MOIST SOUTHERLY FLOW AHEAD OF AN APPROACHING COLD FRONT.
MVFR VISIBILITY IS EXPECTED TO ACCOMPANY PRECIPITATION SUNDAY
BETWEEN DAWN AND MIDDAY. IMPROVEMENT TO VFR IS EXPECTED IN THE
AFTERNOON...AS WINDS VEER BEHIND THE FRONT TO WEST SOUTHWEST.

OUTLOOK...STRONG AND GUSTY NORTHWEST WIND WILL OCCUR LATE SUNDAY
AFTERNOON THROUGH AND MONDAY. VFR CONDITIONS WILL BE THE
RULE...EXCEPT CEILING AND VISIBILITY RESTRICTIONS WILL EXIST WITH
SNOW SHOWERS IN THE MOUNTAINS SUNDAY NIGHT INTO TUESDAY. VFR
WEATHER WILL EXIST WEDNESDAY.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR NCZ033-
     048>052-058-059.
     WINTER WEATHER ADVISORY FROM 3 PM SUNDAY TO 7 PM EST MONDAY
     FOR NCZ033-048>053-058-059-062.
     WINTER STORM WARNING FROM 3 PM SUNDAY TO 7 PM EST MONDAY FOR
     NCZ033-048>052-058.
SC...NONE.

&&

SYNOPSIS...PAT
NEAR TERM...JAT/LG
SHORT TERM...JPT
LONG TERM...PM
AVIATION...JAT/LG

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
948 PM EST SAT DEC 11 2010

NCZ033-048>052-058-130300-
AVERY-MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-GRAHAM-
948 PM EST SAT DEC 11 2010

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 7 AM EST SUNDAY...
...WINTER STORM WARNING IN EFFECT FROM 3 PM SUNDAY TO 7 PM EST
MONDAY...
...WINTER WEATHER ADVISORY IN EFFECT FROM 3 PM SUNDAY TO 7 PM EST
MONDAY...

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...SUNDAY THROUGH FRIDAY.

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

   WINTER WEATHER ADVISORY.
   WINTER STORM WARNING.

.SPOTTER INFORMATION STATEMENT...

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

NCZ053-130300-
BUNCOMBE-
948 PM EST SAT DEC 11 2010

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 7 AM EST SUNDAY...
...WINTER WEATHER ADVISORY IN EFFECT FROM 3 PM SUNDAY TO 7 PM EST
MONDAY...

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...SUNDAY THROUGH FRIDAY.

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

   WINTER WEATHER ADVISORY.

.SPOTTER INFORMATION STATEMENT...

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

NCZ059-130300-
NORTHERN JACKSON-
948 PM EST SAT DEC 11 2010

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 7 AM EST SUNDAY...
...WINTER WEATHER ADVISORY IN EFFECT FROM 3 PM SUNDAY TO 7 PM EST
MONDAY...

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...SUNDAY THROUGH FRIDAY.

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

   WINTER WEATHER ADVISORY.

.SPOTTER INFORMATION STATEMENT...

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

NCZ062-130300-
MACON-
948 PM EST SAT DEC 11 2010

...WINTER WEATHER ADVISORY IN EFFECT FROM 3 PM SUNDAY TO 7 PM EST
MONDAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN NORTH CAROLINA.

.DAY ONE...TONIGHT.

AS PRECIPITATION MOVES INTO THE MOUNTAINS LATE TONIGHT...RAIN WILL
MIX WITH OR EVEN CHANGE TO ALL SNOW...MAINLY IN THE HIGHER
ELEVATIONS. SLEET AND FREEZING RAIN ARE ALSO POSSIBLE. SNOW AND
ACCUMULATIONS WILL BE LIGHT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

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

   WINTER WEATHER ADVISORY.

.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>037-056-057-063>065-068>072-082-
501>510-SCZ001>014-019-130300-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-HART-ELBERT-ALEXANDER-IREDELL-
DAVIE-CATAWBA-ROWAN-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-
948 PM EST SAT DEC 11 2010

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.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

SCATTERED SNOW SHOWERS COULD DEVELOP ACROSS THE NORTHERN FOOTHILLS
AND NORTHWEST PIEDMONT OF NORTH CAROLINA...AND THE MOUNTAINS OF
NORTHEAST GEORGIA AND UPSTATE SOUTH CAROLINA SUNDAY EVENING.
LITTLE TO NO ACCUMULATIONS ARE EXPECTED.

ANOTHER ROUND OF VERY COLD TEMPERATURES IS IN STORE FOR EARLY NEXT
WEEK. TEMPERATURES WILL BE AT LEAST 15 DEGREES BELOW NORMAL INTO
WEDNESDAY. OVERNIGHT LOWS WILL DIP INTO THE TEENS IN MOST PLACES
MONDAY NIGHT AND TUESDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

NONE.

07