[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 250411
SWOMCD
SPC MCD 250411
VAZ000-NCZ000-WVZ000-TNZ000-251015-

MESOSCALE DISCUSSION 2293
NWS STORM PREDICTION CENTER NORMAN OK
1011 PM CST THU DEC 24 2009

AREAS AFFECTED...SWRN VA / WRN NC / EXTREME SERN WV

CONCERNING...FREEZING RAIN

VALID 250411Z - 251015Z

PRECIPITATION WILL MOVE INTO FAR WRN NC AND SWRN VA/EXTREME SERN WV
LATE THIS EVENING INTO THE OVERNIGHT HOURS.  FREEZING RAIN WILL BE
THE PREFERRED P-TYPE...WITH PRECIP RATES INITIALLY STARTING OFF
LIGHT...THEN INCREASING IN INTENSITY TOWARDS THE 09-12Z PERIOD.

RECENT SURFACE ANALYSIS PLACES A WEDGE FRONT/SHALLOW SUB-ZERO ARCTIC
AIRMASS DAMMED TO THE LEE SIDE OF THE APPALACHIANS/BLUE RIDGE MTNS.
EVENING RADAR MOSAIC SHOWS WARM ADVECTION SHOWERS BEGINNING TO
BECOME MORE NUMEROUS OVER THE WRN CAROLINAS AND ERN TN/KY.  THIS
TREND WILL LIKELY CONTINUE AS INCREASING LARGE SCALE ASCENT
ASSOCIATED WITH APPROACHING VIGOROUS SRN MS VALLEY TROUGH GLANCES
THE REGION AS IT LIFTS NEWD TO THE LOWER OH VALLEY BY DAYBREAK.

02Z RUC...21Z ETAKF...00Z NAM FORECAST SOUNDINGS SUPPORT THE NOTION
OF FREEZING RAIN AS THE LOWER TROPOSPHERE SATURATES INDUCING WET
BULBING EFFECTS...WITH THE SURFACE-H9 LAYER REMAINING AOB FREEZING
UNDERNEATH AN ELEVATED WARM NOSE.  THIS IS EVIDENT UNTIL AROUND
12Z...WHEN SURFACE TEMPS MAY WARM TO NEAR 32 DEG F OR HIGHER.  THE
EXCEPTION PERHAPS MAY BE IN THE ROANOKE/LYNCHBURG AREAS AND POINTS
NE...WHERE THE SHALLOW SUB-FREEZING COLD AIR WEDGE MAY LINGER
TOWARDS THE 15-18Z PERIOD.  MODEL GUIDANCE CONSENSUS SHOWS
SUBSTANTIAL FREEZING RAIN RATES BEGINNING EARLIEST ACROSS WRN NC
WITH 0.02-0.05 INCH PER HOUR POSSIBLE THRU 09Z THEN INCREASING UP TO
0.10 INCH PER HOUR THEREAFTER.  FURTHER N OVER SWRN VA...LIGHTER
RATES WILL PROBABLY OCCUR /AOB 0.02 INCH/HR PRIOR TO 09Z/...THEN
INCREASE UP TO 0.10 INCH/HR AROUND 12Z IN THE HEAVIEST SHOWERS.

..SMITH.. 12/25/2009

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

...NOTICE...
SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A
SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR
TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC
FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS.

ATTN...WFO...LWX...RNK...RLX...GSP...MRX...

LAT...LON   37678093 38348024 38257956 37917912 37197923 36517975
            36018120 35738179 35618226 35688247 35848252 35998239
            36278204 36538174 37088155 37678093

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