[MCD] SWOMCD

Sun Jan 21 06:21:27 UTC 2007

ACUS11 KWNS 210626
SWOMCD
SPC MCD 210625 
KYZ000-INZ000-211130-

MESOSCALE DISCUSSION 0089
NWS STORM PREDICTION CENTER NORMAN OK
1225 AM CST SUN JAN 21 2007

AREAS AFFECTED...PORTIONS OF CNTRL KY...EXTREME SRN IND

CONCERNING...WINTER MIXED PRECIPITATION 

VALID 210625Z - 211130Z

AN ASSORTMENT OF PTYPES SHOULD OCCUR THROUGH 12Z AS A LARGE
PRECIPITATION AREA ALONG THE MID-MS RIVER VALLEY EXPANDS EWD.
ALTHOUGH SNOW AND RAIN MAY OCCUR AT TIMES...FREEZING RAIN AND SLEET
WILL LIKELY BECOME THE PRIMARY PTYPES. ICE ACCUMULATIONS IN EXCESS
OF .05 IN/HR WILL BE POSSIBLE...ESPECIALLY TOWARDS 12Z.

AT 06Z...THE SURFACE WET BULB FREEZING LINE WAS LOCATED FROM AROUND
40 NE PAH TO 25 NE BWG TO 25 W CSV. THIS LINE HAS REMAINED NEARLY
STATIONARY OVER THE PAST FEW HOURS AND SHOULD REMAIN AS SUCH FOR THE
NEXT SEVERAL HOURS. RECENT SURFACE OBSERVATIONS INDICATE LIGHT
RAIN/SNOW HAS REACHED WRN KY AND FAR SRN IND. IT WILL CONTINUE A
GRADUAL PROGRESSION EWD AS TOP-DOWN SATURATION OCCURS GIVEN THE DRY
LOW-LEVELS /AS EVIDENCED BY 00Z BNA SOUNDING/. MORE SUBSTANTIAL
PRECIPITATION SHOULD OCCUR TOWARDS 12Z AS A 50-60 KT LLJ FROM THE
LOWER MS VALLEY FOCUSES STRONG WARM/MOIST ADVECTION INTO THE REGION.
BOTH 03Z RUC AND 00Z NAM MODEL GUIDANCE INDICATE SLOW WARMING OF THE
700 TO 850 MB LAYER EVEN AS SATURATION/UPWARD VERTICAL MOTION
OCCURS. POINT FORECAST SOUNDINGS SHOW AN ABOVE FREEZING WARM NOSE
DEVELOPING...WHICH WOULD SUPPORT FREEZING RAIN AND/OR SLEET. THIS IS
ALSO SUPPORTED IN THE 20/21Z SREF GUIDANCE WHICH INDICATE THESE AS
THE MOST LIKELY PTYPES. IF THIS INDEED OCCURS...PRECIPITATION RATES
WOULD CERTAINLY SUPPORT ICE ACCUMULATIONS IN EXCESS OF .05 IN/HR.

..GRAMS.. 01/21/2007

...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...JKL...LMK...PAH...

38498642 38518571 38388506 37948419 37378431 37028498
37348561 37828638 38148684 38378719 