Flooding in North Carolina, February 6 to 7, 2004

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
340 PM EST FRI FEB 6 2004

.DISCUSSION...
SURFACE ANALYSIS SUGGESTS COLD FRONT IS MOVING INTO THE FAR WESTERN
CWFA AT THIS HOUR...AND SHOULD PROGRESS STEADILY EASTWARD THIS
EVENING. BASED ON RADAR TRENDS...WE WILL KEEP CHANCE OF RAIN FOR THE
WEST EARLY...WITH LIKELY TO CATEGORICAL POPS FOR THE EASTERN AND
SOUTHERN MOST ZONES. AS DRY SLOT WORKS IN FROM THE WEST...EXPECT RAIN
TO CUT OFF ABRUPTLY FOR THE CENTRAL AND EASTERN CWFA...AND WE REFLECT
SOME PARTIAL CLEARING FOR THE SOUTHWEST THROUGH MIDNIGHT. RAINFALL
RATES HAVE DIMINISHED SLOWLY THIS AFTERNOON...DUE IN PART TO THE MUCH
MORE STABLE AIR IN RESIDUAL DAMMING REGION. THE DAMMING EPISODE IS
ERODING AS WE SPEAK FROM THE EDGES...AND STILL CANNOT RULE OUT
ISOLATED SEVERE GIVEN OBSERVED SOUNDINGS AS MAJOR CONVECTION
ENCOUNTERS THE THERMAL MOISTURE BOUNDARY SURGING NORTHWEST RIGHT
NOW INTO THE SOUTHEAST PART OF OUR FORECAST AREA. WILL ALSO HAVE TO
MAINTAIN FLOOD WATCH FOR ALL BUT THE EXTREME WESTERN CWFA...WITH
SOME STREAMS/CREEKS APPROACHING BANKFULL AT THIS HOUR IN THE
CENTRAL AND EASTERN CWFA...AND FORECAST FOR SOME RIVER FLOODING EVEN
IN AREAS THAT HAVE SEEN A MARKED DECREASE IN COVERAGE OF CONVECTION.

WE MAINTAINED CHANCES OF PRECIPITATION FOR THE NORTH CAROLINA
MOUNTAINS...EMPHASIZING THE TENNESSEE BORDER COUNTIES AND REFLECTING
A TRANSITION FROM RAIN SHOWERS TO SNOW SHOWERS OVERNIGHT. THIS
EXPECTED TRANSITION SHOULD OCCUR SLOWLY AT FIRST...AND AFFECT
IMMEDIATE TENNESSEE BORDER LOCATIONS FIRST...THEN GO TO ALL SNOW
OVERNIGHT. RAIN/SNOW SHOWER CHANCES FOR THE CENTRAL AND SOUTHERN
MOUNTAINS THROUGH 06Z...THEN THICKNESSES AND COLD ADVECTION SUPPORT
CHANGE TO ALL SNOW FOR THE MOUNTAINS OVERNIGHT.

A DEEP EAST COAST TROF IS FORECAST TO DROP INTO THE SOUTHEAST STATES
TONIGHT...WITH ANOTHER ONE ACCOMPANIED BY A POTENT SHORTWAVE FOR
SATURDAY AFTERNOON. STRONG COLD ADVECTION ADVERTISED ON THE 12Z
RUNS FOR LATE TONIGHT AND ESPECIALLY SATURDAY...AND RESIDUAL
MOISTURE REMAINS QUITE DEEP NOT JUST AT IN THE SURFACE TO 800 MB
LEVEL BUT THROUGH A DEEP LAYER OF THE ATMOSPHERE. WARNING CRITERIA
SNOWS FOR THE WESTERN FACING SLOPES SEEMS ALMOST ASSURED GIVEN THE
SYNOPTIC SETUP LAPSE RATES TOMORROW AND EARLY SATURDAY EVENING
STEEP. WE PAINTED SNOW AMOUNTS OF 2 TO 3 INCHES FOR THE IMMEDIATE
TENNESSEE BORDER AREAS BY TOMORROW EVENING...AND THIS MAY BE
CONSERVATIVE. TOTAL SNOW AMOUNTS IN OUR GRIDS APPROACH 4 INCHES BY
EVENT TERMINATION LATE SATURDAY NIGHT APPEARS ANOTHER SURGE OF
STRONG NORTHWEST FLOW AND ANOTHER ROUND OF STRONG COLD ADVECTION
COULD RESULT IN ANOTHER BRIEF BURST OF HEAVY SNOW FOR THE NORTHERN
MOUNTAINS LATE SATURDAY NIGHT. IT WOULD NOT SURPRISE US AT ALL TO
HEAR OF ACCUMULATIONS APPROACHING HALF A FOOT...IF...AND THIS IS
VERY IMPORTANT...THE ADVERTISED MESOSCALE AND SYNOPTIC FORCING PAN
OUT AS ADVERTISED BY MODELS.

HAVING SAID THAT...WE WILL KEEP WATCH WITH THIS ISSUANCE. EVENING
SHIFT WILL GET AN OPPORTUNITY TO SEE NEW ROUND OF UPPER AIR DATA
AND IF ALL APPEARS TO BE VERIFYING...THEY WILL HAVE THE LIBERTY OF
UPGRADING THE WATCH TO A WARNING.

CONCERNS NOT JUST LIMITED TO SNOW POTENTIAL. WITH COLD ADVECTION...
AND STRONG FORCING WITH SHORTWAVE THEN SUBSIDENCE ON THE BACKSIDE
OF DEPARTING SHORTWAVE...WINDS COULD APPROACH WIND ADVISORY CRITERIA
SATURDAY EVENING...AND ALSO PRODUCE DANGEROUSLY LOW WIND CHILLS
BUFKIT PROFILES EASILY SUPPORT WIND GUSTS INTO THE 40 KT RANGE
FOR HIGHER ELEVATIONS SATURDAY EVENING. WE HAVE ADDRESSED THIS IN THE
CURRENT WINTER STORM WATCH INDIRECTLY.

SURFACE HIGH SHOULD MOVE OFF THE EAST COAST MONDAY MORNING WHILE THE
NEXT SYSTEM TRIES TO TAKE SHAPE OVER THE SRN PLAINS. THE LATEST GFS
ACTIVATES A COASTAL FRONT BY LATE MONDAY...BUT THIS IS DISCOUNTED.
MODELS HAVE BEEN HANDLING THIS NEXT SYSTEM POORLY WHICH LEADS TO A
LOW CONFIDENCE FORECAST. AT THIS POINT...IT WOULD APPEAR THAT THE
BEST SCENARIO IS FOR A WAVE TO FORM OVER THE NW GULF AND TO MOVE
ACROSS THE SOUTHEAST ON TUESDAY AND WEDNESDAY. TIMING OF THE PRECIP
WILL BE BROADENED SLIGHTLY TO BRING THE THREAT OF SOME PRECIP IN
TUESDAY MORNING AND TO HOLD ONTO IT THRU WEDNESDAY LATE. GFS HAS
TRENDED WARMER WITH MID LEVEL THICKNESSES WHICH SUPPORT CHANGING
PRIMARY PRECIP TYPE TO RAIN FOR MOST OF THE EVENT...WITH SOME SNOW
WORKING IN FROM THE WEST LATE IN THE EVENT...BUT THIS IS ALSO NOT
CERTAIN. HIGH PRESSURE IS EXPECTED TO BUILD IN THURSDAY. THE GFS
DEPICTION OF PRECIP MOVING IN WITH SHORT WAVE DROPPING DOWN FROM NW
FRIDAY MORNING IS DISCOUNTED FOR NOW. WILL KEEP FRIDAY DRY.

&&

.PRELIMINARY POINT TEMPS/POPS...
GSP 41 50 25 46 / 60 10 10 00
AND 42 50 26 46 / 60 00 00 00
CLT 42 51 25 46 / 80 00 00 00
HKY 36 45 23 44 / 50 10 10 00
AVL 32 33 21 40 / 50 30 30 10
&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WINTER STORM WATCH NCZ033-048>052-058.
FLOOD WATCH THIS EVENING NCZ033>037-048>050-053>057-064>072-082.
SC...FLOOD WATCH THIS EVENING SCZ003-006>009-012>014-019.
&&

BURRUS/MOORE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
607 AM EST FRI FEB 6 2004

GAZ010-017-018-026-028-029-NCZ033>037-048>059-062>072-082-SCZ001>014-
019-061306-
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-
607 AM EST FRI FEB 6 2004

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

.DAY ONE...

A STRONG COLD FRONT WILL BE MOVING ACROSS THE REGION TODAY WITH
WIDESPREAD RAIN AND A FEW THUNDERSTORMS ACCOMPANYING IT. TEMPERATURES
REMAIN AROUND FREEZING EAST OF THE MOUNTAINS ALONG I-40 WHERE WINTER
STORM WARNINGS AND WINTER WEATHER ADVISORIES ARE IN EFFECT. FOR
FURTHER DETAILS...PLEASE REFER TO THE LATEST WSWGSP ISSUED BY THIS
OFFICE.

WIDESPREAD HEAVY RAIN IS POSSIBLE...AND EVEN EXCESSIVE RAINFALL MAY
OCCUR. A FLOOD WATCH REMAINS IN EFFECT...AND FOR FURTHER
DETAILS...PLEASE REFER TO THE LATEST FFAGSP ISSUED BY THIS OFFICE.

STRONG WIND FIELDS THROUGHOUT THE ATMOSPHERE WILL EXIST TODAY AND IT
IS POSSIBLE THAT STRONG WINDS COULD BE SEEN ACROSS HIGHER ELEVATIONS
OF THE MOUNTAINS WHERE A WIND ADVISORY IS IN EFFECT. AGAIN...PLEASE
REFER TO THE LATEST NPWGSP FOR FURTHER DETAILS.

SOME THUNDERSTORMS WILL BE POSSIBLE AS WELL...AND STRONG WINDS COULD
BE TRANSPOSTED TO THE SURFACE BY THESE STORMS. A SEVERE WEATHER
OUTLOOK HAS BEEN ISSUED...AND REFER TO SPSGSP FOR DETAILS.

.DAYS TWO THROUGH SEVEN...

COLD AIR WILL SPILL INTO THE REGION STARTING TONIGHT AND WITH THE
ADDITION OF NORTHWEST WINDS AND UPSLOPE MOISTURE...SNOW SHOWERS ARE
LIKELY TO OCCUR ACROSS THOSE NORTH CAROLINA COUNTIES BORDERING
TENNESSEE. FOR FURTHER DETAILS...PLEASE REFER TO THE LATEST WINTER
STORM OUTLOOK...SPSGSP...ISSUED BY THIS OFFICE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED.

55

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1211 PM EST FRI FEB 6 2004

NCZ057-071-072-082-SCZ009-011>014-019-062200-
ABBEVILLE SC-CABARRUS NC-CHESTER SC-GREENWOOD SC-LAURENS SC-
MECKLENBURG NC-ROWAN NC-UNION SC-UNION NC-YORK SC-
1211 PM EST FRI FEB 6 2004

...THUNDERSTORMS WITH STRONG WIND GUSTS POSSIBLE THIS AFTERNOON...

THE COMBINATION OF STRONG WIND FIELDS THROUGHOUT THE ATMOSPHERE AND
AN AREA OF INCREASING INSTABILITY JUST TO OUR SOUTH...WILL GIVE RISE
TO A RISK OF THUNDERSTORMS PRODUCING STRONG OR DAMAGING WIND GUSTS.
IN ADDITION...AN AREA OF LOW PRESSURE WILL MOVE NORTHEAST ALONG THE
ZONE OF INSTABILITY...CREATING THE POTENTIAL FOR ISOLATED WEAK
TORNADOES. THE AREA WITH THE GREATEST RISK FOR SEVERE THUNDERSTORMS
WILL BE MAINLY FROM ELBERTON AND GREENWOOD...NORTHEAST TO CHESTER AND
MONROE. AREAS JUST TO THE NORTH ARE UNDER A SIMILAR...BUT SMALLER
THREAT.

SPOTTER GROUPS SHOULD BE PREPARED TO ACTIVATE QUICKLY LATE THIS
AFTERNOON AND THIS EVENING. DISPATCHERS SHOULD ENSURE COUNTY
EMERGENCY MANAGEMENT OFFICIALS ARE AWARE OF THIS INFORMATION.

STAY TUNED TO NOAA WEATHER RADIO OR YOUR FAVORITE MEDIA OUTLET FOR
THE LATEST UPDATES CONCERNING THIS POTENTIAL SEVERE WEATHER
SITUATION.

RWH