[MCD] SWOMCD

Sat Jan 20 06:21:44 UTC 2007

ACUS11 KWNS 200624
SWOMCD
SPC MCD 200623 
TXZ000-201030-

MESOSCALE DISCUSSION 0085
NWS STORM PREDICTION CENTER NORMAN OK
1223 AM CST SAT JAN 20 2007

AREAS AFFECTED...S PLAINS/CAPROCK OF NWRN TX

CONCERNING...FREEZING RAIN 

VALID 200623Z - 201030Z

LIGHT FREEZING RAIN OCCASIONALLY MIXED WITH SLEET WILL PERSIST
THROUGH THE OVERNIGHT HOURS. 3-HR PRECIP ACCUMULATIONS FROM .05 TO
.10 IN WILL BE LIKELY.

SURFACE TEMPERATURES ACROSS THE S PLAINS/CAPROCK REGION HAVE LEVELED
OFF FROM 30 TO 32 DEGREES. AT 06Z...THE SURFACE FREEZING LINE WAS
LOCATED FROM MAF TO 20 W ABI TO 40 SE CDS. 06Z MAF AND 03Z REESE TX
OBSERVED SOUNDINGS WERE INDICATIVE OF FREEZING RAIN WITH OCCASIONAL
SLEET ACROSS THE S PLAINS/CAPROCK REGION. NAMELY...A 100 MB DEEP
ABOVE FREEZING WARM NOSE BETWEEN 725 TO 825 MB IN THE 06Z MAF
SOUNDING TO A LESS THAN 50 MB ABOVE FREEZING LAYER IN THE 03Z REESE
SOUNDING. BOTH 00Z NAM AND 03Z RUC POINT FORECAST SOUNDINGS CONTINUE
THE TREND OF A SLIGHT COOL BIAS /AROUND 1 DEG C/ WITH THE ELEVATED
WARM LAYER. THE THERMODYNAMIC PROFILE FROM THE SURFACE TO 700 MB IS
EXPECTED TO CHANGE LITTLE THROUGH 12Z...WITH OCCASIONAL PHASE
CHANGES LIKELY A RESULT OF SUBTLE VARIATIONS IN UPWARD VERTICAL
MOTION.

EVENING SATELLITE IMAGERY HAS DEPICTED A WELL-DEFINED
MID/UPPER-LEVEL SUB-TROPICAL MOISTURE PLUME FROM THE SRN TIP OF BAJA
CA NEWD ACROSS THE SRN HIGH PLAINS. THIS PLUME WAS LOCATED
DOWNSTREAM OF A QUASI-STATIONARY UPPER LOW IN FAR NWRN SONORA.
ALTHOUGH THIS LOW WILL BEGIN TO ACCELERATE EWD BY 12Z...THE MOISTURE
PLUME SHOULD ONLY SHIFT SLOWLY EWD. IN ADDITION...LOW-LEVEL WAA /AS
INFERRED FROM VEERING IN 06Z MAF SOUNDING/ IN WARM/MOIST CONVEYOR
BELT REGION IS EXPECTED TO REMAIN NEARLY STATIONARY OVERNIGHT.
THUS...LIGHT PRECIPITATION FOR THE NEXT SEVERAL HOURS WILL CONTINUE.

..GRAMS.. 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...SJT...LUB...MAF...

33770170 34449996 34139979 33150010 32440036 32140076
31550131 31960209 32520269 33030255 