[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 080306
SWOMCD
SPC MCD 080305
PAZ000-WVZ000-OHZ000-KYZ000-VAZ000-TNZ000-INZ000-080830-

MESOSCALE DISCUSSION 0375
NWS STORM PREDICTION CENTER NORMAN OK
0905 PM CST FRI MAR 07 2008

AREAS AFFECTED...PORTIONS OF MIDDLE/ERN TN...CENTRAL/ERN
KY...SRN/ERN IND...MUCH OF OHIO...WRN WV AND WRN PA

CONCERNING...WINTER MIXED PRECIPITATION

VALID 080305Z - 080830Z

A MIX OF FREEZING RAIN/SLEET AND SNOW WILL DEVELOP AND EXPAND IN
AREAL COVERAGE ACROSS THE REGION THROUGH 09Z. HRLY LIQUID EQUIVALENT
PRECIPITATION RATES OVER 0.15 INCH/HR WILL BE POSSIBLE WITHIN
CONVECTIVE CELLS.

LATEST IR SAT IMAGERY SHOWS A LARGE AREA OF EXPANDING/COOLING CLOUD
TOPS FROM MIDDLE TN NWD THROUGH THE OHIO VALLEY. THIS IS INDICATIVE
OF STRENGTHENING MID LEVEL FRONTOGENETIC FORCING IN RESPONSE TO THE
APPROACH OF AN UPPER JET OVER GA/AL THAT WAS ROUNDING THE BASE OF
THE LOWER MS VALLEY UPPER TROUGH. BOTH THE 00Z BNA AND ILN SOUNDINGS
SHOW SUFFICIENT ELEVATED INSTABILITY /100-200 J/KG OF MUCAPE/ TO
SUPPORT CONVECTIVE PRECIPITATION WITH ISOLATED TSTMS. WHERE THE
THERMODYNAMIC PROFILE WILL CONTINUE TO SUPPORT ALL SNOW /ROUGHLY
ALONG AND NW OF A LINE FROM NEAR BNA NEWD TO LEX TO FKL THROUGH 09Z/
STRONG MID LEVEL FRONTOGENETIC FORCING IN THE 4-6 KM LAYER /PER 00Z
SOUNDINGS AND RECENT VWP DATA/ WILL SUPPORT SEVERAL NE-SW ORIENTED
HEAVY SNOW BANDS WITH HRLY SNOWFALL RATES AROUND 1 INCH/HR. ALONG
AND JUST NORTH OF THE TRANSITION ZONE FROM SNOW TO MIXED PRECIP
/FROM WCENTRAL KY INTO SERN/CENTRAL OH...THE ELEVATED INSTABILITY
WILL SUPPORT LOCALLY HEAVY SNOWFALL RATES UP TO 2 IN/HR. FURTHER
SE...AN EXTRAPOLATION OF THE 00Z BNA/ILN AND RNK SOUNDINGS INDICATES
THE PRESENCE OF AN ELEVATED WARM LAYER AND STRONG WAA. SOUTHEAST OF
THE TRANSITION LINE TO HEAVY SNOW...MODERATE TO HEAVY SLEET SHOWERS
ARE EXPECTED MUCH OF MIDDLE TN...ERN KY...NEWD INTO SERN OH. FURTHER
EAST OF THIS ZONE...A SUFFICIENTLY DEEP ELEVATED WARM LAYER WILL
SUPPORT MAINLY FREEZING RAIN OVER FAR ERN KY...WRN WV INTO SWRN PA.
CONTINUED LOW LEVEL CAA /SUPPORTED BY MODEST PRESSURE RISES/ AND
WET-BULB COOLING WILL SUPPORT A SWD MOVEMENT OF THE FREEZING LINE
FROM MIDDLE INTO PORTIONS OF ERN TN OVER THE NEXT SEVERAL HOURS.
THUS A CHANGEOVER TO MODERATE SLEET/FREEZING RAIN IS EXPECTED IN
THIS AREA BY 06Z.

..CROSBIE.. 03/08/2008

...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...PBZ...RLX...CLE...MRX...JKL...ILN...LMK...IWX...OHX...IND...PAH...MEG...

41588334 40318547 38958716 37988771 36178838 35708705
35888482 36828309 37988198 39838005 41688002 41898032



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