[MCD] SWOMCD

Sat Jan 20 01:52:53 UTC 2007

ACUS11 KWNS 200155
SWOMCD
SPC MCD 200154 
OKZ000-TXZ000-200600-

MESOSCALE DISCUSSION 0084
NWS STORM PREDICTION CENTER NORMAN OK
0754 PM CST FRI JAN 19 2007

AREAS AFFECTED...NORTHWEST TX/SOUTHWEST OK

CONCERNING...WINTER MIXED PRECIPITATION 

VALID 200154Z - 200600Z

A MIX OF FREEZING RAIN/SLEET IN ADDITION TO SOME SNOW WILL LIKELY
PERSIST THROUGH MUCH OF THE EVENING FROM THE TX SOUTH PLAINS/CAPROCK
VICINITY INTO PORTIONS OF NORTH CENTRAL TX AND SOUTHWEST/FAR SOUTH
CENTRAL OK. A LIGHT ICE GLAZE IS POSSIBLE.

IN ASSOCIATION WITH INCREASING PRECIPITATION RATES ACROSS MUCH OF
NORTHWEST TX INTO FAR SOUTHWEST/SOUTH CENTRAL OK...WITH TEMPERATURES
BORDERLINE AROUND FREEZING...SURFACE OBSERVATIONS CONTINUE TO
GENERALLY REFLECT A MIX OF FREEZING RAIN/SOME SLEET ACROSS THIS
CORRIDOR.

THE 00Z AMARILLO RAOB FEATURES A 100 MB DEEP ELEVATED
ABOVE-FREEZING LAYER CENTERED AROUND 750 MB...CONSISTENT WITH THE
MIX OF SLEET/FREEZING RAIN AND SOME SNOW THAT HAS BEEN PREVALENT
ACROSS NORTHWEST TX. FARTHER EAST...THE 00Z NORMAN OBSERVED RAOB
FEATURES ABOVE FREEZING WARM LAYER /NEARLY 2 C/ CENTERED AROUND 770
MB...WITH AN ABUNDANCE OF DRY AIR IN THE LOW LEVELS BELOW 800 MB.
BASED ON THESE OBSERVED SOUNDINGS...IT APPEARS 18Z NAM/18Z GFS POINT
SOUNDINGS CONTINUE TO FEATURE A SLIGHT COOL BIAS /1-2 DEG C/ WITHIN
THE CRITICAL ELEVATED WARM LAYER. WITH LITTLE THERMAL
ADVECTION/FLUCTUATION...THIS SUGGESTS THE ONSET OF PREDOMINANT SNOW
WILL REMAIN DELAYED AS THE ELEVATED WARM LAYER STRUGGLES TO COOL
BELOW FREEZING...WITH A CONTINUANCE OF A FREEZING RAIN/SLEET MIX
FROM THE CAPROCK/TX SOUTH PLAINS INTO SOUTHWEST OK THIS EVENING.
THIS SCENARIO MAY SUPPORT LIGHT ICE ACCUMULATIONS.

..GUYER.. 01/20/2007

...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...OUN...LUB...AMA...MAF...

35420028 35389904 34769773 34049789 34199943 33580040
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