[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 300152
SWOMCD
SPC MCD 300152 
OKZ000-KSZ000-TXZ000-300445-

MESOSCALE DISCUSSION 2492
NWS STORM PREDICTION CENTER NORMAN OK
0752 PM CST MON NOV 29 2004

AREAS AFFECTED...NWRN TX AND SWRN/CENTRAL OK

CONCERNING...PRECIPITATION TRENDS...WINTER PRECIPITATION 

VALID 300152Z - 300445Z

DYNAMIC LIFT WILL INCREASE OVER THE REGION THROUGH 06Z...WITH THE
POSSIBLE DEVELOPMENT OF A MODERATE TO HVY SNOW BAND ALONG AN AXIS
FROM NEAR CDS-OKC-PNC BETWEEN 06-09Z. BEFORE MID LEVEL SATURATION
OCCURS...THE PROBABILITY FOR INCREASED LOW LEVEL LIFT NORTH OF
SURFACE BOUNDARY AND IN SUBFREEZING AIRMASS WILL LEAD TO THE
DEVELOPMENT OF LIGHT FREEZING RAIN/DRIZZLE ACROSS SWRN/CENTRAL OK
BEFORE ONSET OF SNOWFALL. 

LATEST IR IMAGERY SUGGESTS THAT COOLING CLOUD TOPS OVER SWRN/WRN TX
IS A RESULT OF INCREASINGLY STRONG FRONTOGENETICAL FORCING
OVERSPREADING THE REGION AHEAD OF EJECTING SHORTWAVE TROUGH. ECHO
DEVELOPMENT SEEN ON LOCAL RADAR FROM LBB FURTHER  SUPPORTS THAT MID
LEVELS WERE MOISTENING AND THAT SUFFICIENT MOISTENING THROUGH THE
-14 TO -16 DEG C LAYER /AROUND 600 MB/ WILL OCCUR TO SUPPORT THE
DEVELOPMENT OF MDT-HVY SNOW BY LATER TONIGHT AS STRONGEST MID LEVEL
FRONTOGENESIS IN THIS LAYER FOCUSES ALONG AFOREMENTIONED AXIS. STEEP
MID LVL LAPSE RATES WILL SUPPORT CONVECTIVE SNOW DEVELOPMENT THE
POTENTIAL FOR 1 IN/HR SNOWFALL RATES. IN ADDITION TO MID LEVEL
FRONTOGENESIS...LOW LEVEL FRONTOGENESIS ALONG AND NORTH OF SFC FRONT
EXTENDING ACROSS NRN TX AS EVIDENT BY RECENT BACKING FLOW IN THE 2-3
KM LAYER FROM THE VWP AT FREDERICK OK. BEFORE MID LEVEL SATURATION
OCCURS...EXPECT INCREASE IN LIGHT FREEZING PRECIPITATION NORTH OF
SFC FREEZING LINE WHICH SHOULD EXTEND ALONG AN AXIS FROM OKC TO LAW
BY 06Z GIVEN CURRENT EXTRAPOLATION.

..CROSBIE.. 11/30/2004

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

...NOTICE...
SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A 
SCHEDULED BASIS...FOUR TIMES A DAY...BETWEEN 05-06 UTC...
11-12 UTC...17-18 UTC...AND 23-00 UTC AS SIGNIFICANT SHORT
RANGE WINTER WEATHER EVENTS UNFOLD.  THIS SCHEDULE WILL BE
USED FROM DECEMBER 1 THROUGH FEBRUARY 28 TO ALLOW PARTNERS
AND USERS TO BETTER ANTICIPATE THE TIMING OF SPC WINTER WEATHER
MESOSCALE DISCUSSIONS.

ATTN...WFO...TSA...ICT...FWD...OUN...SJT...LUB...AMA...MAF...

33430160 34640034 36329867 37159736 36069650 34739698
33989809 33419872 32719952 32860100 

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