[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 250634
SWOMCD
SPC MCD 250633 
MSZ000-LAZ000-TXZ000-251230-

MESOSCALE DISCUSSION 2575
NWS STORM PREDICTION CENTER NORMAN OK
1233 AM CST SAT DEC 25 2004

AREAS AFFECTED...ERN UPPER COASTAL PLAIN OF SE TX/SRN LA

CONCERNING...WINTER MIXED PRECIPITATION 

VALID 250633Z - 251230Z

...POTENTIAL FOR SNOW/SLEET DEVELOPING ACROSS PORTIONS OF SRN LA
BEFORE 12Z...

LATEST SFC ANALYSIS SHOWS FREEZING LINE EXTENDS FROM OCH/JAS/ARA/HSA
AS OF 06Z. RECENT RADAR IMAGERY SHOWS PRECIPITATION IS OCCURRING
ALOFT...WITH PRECIPITATION BEING REPORTED AT THE SFC AS FAR EAST AS
NEW ORLEANS. WITH UPSTREAM VORT MAX QUICKLY APPROACHING THE
AREA...IT WILL NOT TAKE MUCH TIME BEFORE LOW LEVELS BECOME
SATURATED. CONVECTIVE CELLS ARE PRECIPITATING INTO THE LOWER
LAYERS...VIA A SEEDER/FEEDER TYPE PROCESS AND EFFECTIVELY
COOLING/MOISTENING THE LAYER. CURRENT DEWPOINTS ARE LOW...GENERALLY
IN THE LOWER 20S WITH WETBULB ZERO TEMPERATURES BELOW FREEZING AS
WELL. 

00Z ETA IS ALREADY TOO SLOW IN DEVELOPING THE WAA PRECIPITATION
FIELD...GIVEN CURRENT RADAR/SATELLITE OBSERVATIONS. THERMODYNAMIC
PROFILES YIELD MAINLY SNOW WITH POSSIBLY SOME SLEET OR FREEZING RAIN
MIXING IN. HOWEVER THE COMBINATION OF STRONG MID LEVEL FRONTOGENESIS
AND STRONG DYNAMICAL FORCING SHOULD COOL THE COLUMN SUFFICIENTLY TO
SUPPORT ALL FROZEN PRECIPITATION.

..TAYLOR.. 12/25/2004

...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...LIX...LCH...HGX...

29469462 29939495 30679418 30839338 30819179 30739068
30498969 30198901 29338950 29209050 29649275 29789320 

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