MESO: Mesoscale Discussion 0092

ACUS11 KWNS 030009
SWOMCD
SPC MCD 030008
KSZ000-NEZ000-COZ000-WYZ000-030415-

MESOSCALE DISCUSSION 0092
NWS STORM PREDICTION CENTER NORMAN OK
0608 PM CST THU FEB 02 2012

AREAS AFFECTED...NERN CO...SWRN NEB...NWRN KS...SERN WY

CONCERNING...HEAVY SNOW

VALID 030008Z - 030415Z

FOR MID/LATE EVENING INTO THE OVERNIGHT HOURS...THE PRIMARY AREA OF
CONCERN FOR ENHANCED SNOWFALL RATES WILL BE INVOF THE FRONT RANGE OF
THE ROCKIES FROM SERN WY INTO NERN CO. ELSEWHERE ACROSS NERN
CO...NWRN KS...SWRN NEB...AND SERN WY...PRECIP COVERAGE/INTENSITY
WILL LIKELY REMAIN LIMITED.

WATER VAPOR LOOP DURING THE PAST 12 HRS REVEALS LITTLE CHANGE IN THE
POSITION OF THE MEAN CENTER OF A LARGE MID-LEVEL CYCLONE OVER THE
WRN CONUS...CENTERED OVER THE FOUR-CORNERS REGION. THIS IS A
REFLECTION OF ITS DISASSOCIATION FROM THE NRN STREAM WITHIN A HIGHLY
AMPLIFIED FLOW REGIME...AND LITTLE CHANGE IN THE CHARACTER/POSITION
OF THE CYCLONE IS ANTICIPATED DURING THE NEXT SEVERAL HOURS. AS
SUCH...THE PRIMARY FORCING FOR ASCENT IN ASSOCIATION WITH THE
CYCLONE WILL EMANATE FROM WAA EMBEDDED WITHIN THE WRN BRANCH OF A
BIFURCATED WARM CONVEYOR BELT WRAPPING AROUND THE CYCLONE. THIS
ASCENT IS SUPPORTING A NWD-LIFTING BROAD ZONE OF MAINLY LIGHT RAIN
AND SNOW OVER ERN CO AND WRN KS...WHICH WILL LIKELY CONTINUE TO LIFT
NWD AND MOVE INTO SWRN NEB AFTER 01Z.

FOLLOWING THIS INITIAL ACTIVITY...A WELL-DEFINED DRY SLOT WRAPPING
AROUND THE ERN SEMICIRCLE OF THE CYCLONE WILL LIKELY LIMIT THE
COVERAGE/INTENSITY OF PRECIPITATION ACROSS A LARGE PART OF THE AREA
BY LATE EVENING INTO THE OVERNIGHT HOURS. OUTSIDE OF A NARROW
CORRIDOR OF UPSLOPE-ENHANCED SNOW /WITH RATES AROUND 1 IN PER HR/
AFFECTING THE FRONT RANGE OF THE ROCKIES AND ADJACENT FOOTHILLS FROM
SERN WY SWD TOWARD THE PALMER DIVIDE...DEEP-LAYER FORCING FOR ASCENT
OWING THE TO THE LACK OF DCVA AND THE PRESENCE OF ONLY WEAK
LOW/MID-LEVEL FRONTOGENESIS WILL LIKELY SUPPRESS THE
COVERAGE/INTENSITY OF PRECIP DURING THE OVERNIGHT HOURS. THE AREA
MOST SUSCEPTIBLE FOR SNOW AS THE PREDOMINANT PRECIP TYPE IS EXPECTED
TO BE CONFINED TO WITHIN 75 MILES ALONG AND EAST OF THE FRONT RANGE
OF THE ROCKIES BY 03Z /OWING TO CAA PROVIDED BY A DEVELOPING BARRIER
JET/...WITH THIS AREA ONLY GRADUALLY EXPANDING EWD THROUGH THE
NIGHTTIME HOURS IN CONCERT WITH NOCTURNAL COOLING.

WHILE THE LOW-LEVEL PRESSURE GRADIENT IS EXPECTED TO MODESTLY
TIGHTEN THROUGH THE NIGHT -- ATTRIBUTABLE TO PRESSURE RISES TO THE
NORTH -- MULTI-MODEL CONSENSUS SUGGESTS THAT SUSTAINED WIND SPEEDS
WILL GENERALLY REMAIN AOB 25 MPH. WITH THE ABSENCE OF AN EVEN
TIGHTER SFC PRESSURE GRADIENT...THIS SHOULD SERVE TO LIMIT THE
POTENTIAL FOR BLIZZARD CONDITIONS INTO THE OVERNIGHT HOURS.

..COHEN.. 02/03/2012

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

ATTN...WFO...LBF...GLD...PUB...BOU...CYS...

LAT...LON 38450366 38610493 39510542 41170547 41690397 41350187
39810133 39130169 38740239 38450366

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