[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 220545
SWOMCD
SPC MCD 220544 
OKZ000-TXZ000-221145-

MESOSCALE DISCUSSION 2558
NWS STORM PREDICTION CENTER NORMAN OK
1144 PM CST TUE DEC 21 2004

AREAS AFFECTED...SRN TX PANHANDLE...TX SOUTH PLAINS NEWD INTO SWRN
OK

CONCERNING...HEAVY SNOW 

VALID 220544Z - 221145Z

HVY SNOW WITH HOURLY ACCUMULATIONS AROUND 1 INCH ARE ANTICIPATED TO
DEVELOP BETWEEN 06-09Z OVER THE SRN TX PANHANDLE/FAR NWRN TX...AND
BETWEEN 09-12Z OVER SWRN OK. THE AXIS OF HEAVIEST SNOW IS
ANTICIPATED TO BE ROUGHLY 20 MILES EITHER SIDE OF A LINE PVW TO CDS
TO LAW DURING THIS PERIOD.

RADAR RETURNS FROM KAMA INDICATES LOW-MID LEVEL SATURATION WAS
OCCURRING FAIRLY QUICKLY AS MID LVL LOW ROTATES OUT OF NM. THIS
TREND SHOULD SUPPORT SNOW DEVELOPMENT OVER THE SWRN TX PANHANDLE/NRN
TX SOUTH PLAINS REGION OVER THE NEXT FEW HOURS. STRONGEST LIFT
ASSOCIATED WITH DEFORMATION ZONE IN THE 700-600 MB LAYER COINCIDENT
WITH THERMODYNAMIC PROFILES SUPPORTIVE OF HVY SNOW WILL OVERSPREAD
THE AREA AS THE MID LEVEL LOW MIGRATES FROM CENTRAL NM INTO THE SERN
TX PANHANDLE BY 12Z. MID LEVEL FRONTOGENETIC FORCING IS ANTICIPATED
TO BEGIN AS STRONG MID LEVEL SPEED MAX OVER SRN NM/FAR WRN TX
ROTATES NEWD INTO NWRN TX. AXIS OF STRONGEST MID LEVEL FRONTOGENETIC
FORCING SHOULD DEVELOP ROUGHLY ALONG THE MID LEVEL LOW PATH FROM
NEAR LBB TO CDS TO LAW THROUGH 12Z. 05Z SFC ANALYSIS INDICATES THAT
SFC DEWPT DEPRESSIONS REMAIN FROM 10-15 DEG F WHICH ALONG WITH ABOUT
A 100-150 MB DEEP DRY LAYER ABOVE SFC SHOULD LIMIT INITIAL
DEVELOPMENT AND INTENSITY OF SNOW UNDER THE STRONG MID LEVEL
FORCING. DESPITE A CONTINUATION OF LOW LVL DRY AIR ADVECTING IN ON
NELY SFC WINDS...SUFFICIENTLY STRONG PRECIPITATION DEVELOPMENT
SHOULD OFFSET THE DRYING WHICH WILL SUPPORT HVY SNOWFALL AT THE SFC
WITHIN 1-2 HOURS OF LIGHT SNOW DEVELOPMENT. DEGREE OF LIFT
ASSOCIATED WITH BANDED PRECIP ALONG WITH MID LEVEL LAPSE RATES
AROUND 7 DEG C/KM WILL SUPPORT CONVECTIVE SNOWFALL RATES AROUND 1
INCH/HR.

..CROSBIE.. 12/22/2004

...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 00-01 UTC...
06-07 UTC...12-13 UTC...AND 18-19 UTC AS SIGNIFICANT SHORT
RANGE WINTER WEATHER EVENTS UNFOLD.  THIS SCHEDULE WILL BE
USED FROM DECEMBER 1 THROUGH FEBRUARY 28.

ATTN...WFO...OUN...LUB...AMA...

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