[MCD] SWOMCD

Thu Dec 21 00:21:37 UTC 2006

ACUS11 KWNS 210022
SWOMCD
SPC MCD 210022 
NEZ000-KSZ000-COZ000-WYZ000-210615-

MESOSCALE DISCUSSION 2288
NWS STORM PREDICTION CENTER NORMAN OK
0622 PM CST WED DEC 20 2006

AREAS AFFECTED...NERN CO / FAR SERN WY / SWRN NEB

CONCERNING...BLIZZARD 

VALID 210022Z - 210615Z

PERIODS OF HEAVY SNOW WITH HOURLY RATES OF UP TO 1-1.5 INCHES ARE
EXPECTED TO CONTINUE THROUGH 21/06Z.  WHEN COUPLED WITH NLY/NELY
WINDS OF 30-40 MPH...BLIZZARD OR NEAR BLIZZARD CONDITIONS WILL
CONTINUE FROM THE CHEYENNE RIDGE AND CO FRONT RANGE EWD INTO THE
HIGH PLAINS.

LATE AFTERNOON/EARLY EVENING WATER VAPOR IMAGERY INDICATES DEEP
UPPER LOW BEGINNING TO DEVELOP MORE NEWD INTO SWRN KS WITH STRONGEST
HEIGHT FALLS SHIFTING THROUGH CNTRL/ERN KS AND SRN NEB.  INITIAL
DEFORMATION BAND OVER MUCH OF NEB WWD ACROSS ERN CO HAS WEAKENED
THIS AFTERNOON...PERHAPS IN ASSOCIATION WITH NWD DEVELOPMENT OF
SYSTEM DRY SLOT ALONG ERN PERIPHERY OF MID-LEVEL CIRCULATION. 
HOWEVER...IR CLOUD TOP TEMPERATURES AND RADAR REFLECTIVITY DATA SHOW
THE INITIAL STAGES OF SECONDARY DEFORMATION ZONE DEVELOPMENT FROM
NEAR AKO EWD THROUGH IML TO NEAR BBW.  WATER VAPOR IMAGERY AND SHORT
TERM GUIDANCE SUGGEST THAT THIS EVOLUTION IS LIKELY IN RESPONSE TO
STRONG VORTICITY MAXIMUM ROTATING AROUND UPPER LOW.

AS THIS VORTICITY MAXIMUM CONTINUES N AND THEN NW OF UPPER
TONIGHT...EXPECT THAT PRECIPITATION SHIELD WILL EXPAND/INTENSIFY
FROM NERN CO EWD INTO CNTRL NEB WITH HOURLY SNOW RATES APPROACHING
1-1.5 INCHES.  21/00Z DEN SOUNDING INDICATES A SHALLOW LAYER
/BETWEEN 550-500 MB/ OF CONDITIONALLY UNSTABLE LAPSE RATES WITH
ISOLATED LIGHTNING STRIKES OBSERVED ALONG THE FRONT RANGE THIS
AFTERNOON AND EARLY EVENING.  ANY EMBEDDED CONVECTIVE ELEMENTS WILL
BE CAPABLE OF SNOW RATES APPROACHING TWO INCHES/HOUR.

IN ADDITION TO THE HEAVY SNOW...STRONG NLY/NELY WINDS OF 25-35 MPH
GUSTING TO 40-45 MPH ARE RESULTING IN BLIZZARD OR NEAR BLIZZARD
CONDITIONS ACROSS THE REGION...A TREND WHICH SHOULD CONTINUE THROUGH
21/06Z.  EXPECT SNOW RATES TO BEGIN TO DIMINISH ALONG THE FRONT
RANGE THEREAFTER.

..MEAD.. 12/21/2006

...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...LBF...GLD...PUB...BOU...CYS...

39240473 40540506 41410494 42080420 42090304 41200197
40710160 39730172 38980230 38710372 