[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 220036
SWOMCD
SPC MCD 220035 
ILZ000-KYZ000-MOZ000-ARZ000-220430-

MESOSCALE DISCUSSION 2556
NWS STORM PREDICTION CENTER NORMAN OK
0635 PM CST TUE DEC 21 2004

AREAS AFFECTED...S-CENTRAL/SERN MO AND SRN IL

CONCERNING...PRECIPITATION TRENDS...WINTER PRECIPITATION 

VALID 220035Z - 220430Z

MIXED WINTER PRECIPITATION WILL DEVELOP ACROSS S-CENTRAL/SERN MO
ENEWD INTO SRN IL BETWEEN 03-06Z. INITIAL RAINFALL WILL MIX WITH AND
GRADUALLY CHANGE TO SNOW FROM NW TO SE...WITH LOCALIZED MOD/HVY SNOW
POSSIBLE LATER TONIGHT.

AT 22/00Z...SYNOPTIC COLD FRONT EXTENDED FROM CENTRAL IND SWWD
ACROSS SRN MO INTO CENTRAL OK...WITH SURFACE WET BULB FREEZING LINE
TRAILING THE BOUNDARY BY 30-40NM. COLD AND RELATIVELY DRY AIR WILL
CONTINUE TO FILTER SWD ACROSS SRN MO/SRN IL THROUGHOUT THE OVERNIGHT
PERIOD AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL/NRN PLAINS.
MEANWHILE...MOIST FLOW FROM THE WRN GULF OF MEXICO CONTINUES TO
STREAM NWD IN ADVANCE OF SURFACE LOW OVER NERN TX. WARM ADVECTION
PRECIPITATION WITH EMBEDDED CONVECTION WILL CONTINUE TO INCREASE
THIS EVENING ACROSS CENTRAL/NRN AR...OVER THE TOP OF A
QUASI-STATIONARY FRONT EXTENDING NEWD FROM THE SURFACE LOW ACROSS
CENTRAL AR.  

MID-LEVEL FLOW FIELD IS PROGGED TO BECOME INCREASINGLY FRONTOGENETIC
ON NRN EDGE OF WARM ADVECTION IN 850-700MB LAYER. THESE TRENDS ARE
ALREADY UNDERWAY WITH A NOTED INCREASE IN RADAR REFLECTIVITY OVER
SERN MO/SRN IL IN VICINITY OF MODERATELY STRONG 700MB BAROCLINIC
ZONE. DRY BOUNDARY LAYER WILL SLOW ONSET OF PRECIP...BUT WILL ALSO
CONTRIBUTE TO STRONG EVAPORATIVE COOLING AT LOW-LEVELS RESULTING A
FAVORABLE PROFILES FOR SNOW. COMBINED WITH COLD
ADVECTION...PRECIPITATION SHOULD CHANGE TO SNOW BETWEEN 03-06Z WITH
RAIN-SNOW LINE ADVANCING SEWD TOWARD FAR SERN MO AND FAR SRN IL LATE
TONIGHT. ELEVATED CONVECTION MAY LEAD TO BURSTS OF HEAVY SNOW BY 06Z
ACROSS THE DISCUSSION AREA AS MARGINAL INSTABILITY AROUND LIT
/MUCAPE 100 J/KG/ ADVECTS NEWD DURING THE NEXT SEVERAL HOURS.

..BANACOS.. 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...PAH...MEG...LSX...SGF...

36509247 36559290 36659306 36849285 37099248 37459183
37879065 38408924 38418886 38438806 38188803 37738824
37328872 37168912 36509027 

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