[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 111231
SWOMCD
SPC MCD 111231 
AZZ000-UTZ000-NVZ000-111830-

MESOSCALE DISCUSSION 0232
NWS STORM PREDICTION CENTER NORMAN OK
0631 AM CST SAT MAR 11 2006

AREAS AFFECTED...CNTRL AND NRN AZ INTO SRN UT

CONCERNING...HEAVY SNOW 

VALID 111231Z - 111830Z

HEAVY SNOW IS EXPECTED TO BECOME INCREASINGLY WIDESPREAD TODAY. 
LOCALIZED SNOW RATES APPROACHING 2-3 INCHES/HOUR WILL BE POSSIBLE
WITH EMBEDDED CONVECTIVE ELEMENTS.  ADDITIONALLY...INCREASING
GRADIENT FLOW WILL RESULT IN CONSIDERABLE BLOWING AND 
DRIFTING.

TRENDS IN REGIONAL RADAR IMAGERY SHOW AN EXPANDING PRECIPITATION
SHIELD FROM SERN CA/NRN BAJA NEWD INTO SWRN AND CNTRL AZ...IN
ADVANCE OF A SHORTWAVE TROUGH MOVING ONTO THE SRN CA COAST. THUS
FAR...WINTER PRECIPITATION ALONG THE MOGOLLON RIM AND PLATEAU REGION
HAS BEEN DRIVEN BY OROGRAPHIC FORCING OWING TO RELATIVELY STRONG
SWLY LOW-LEVEL FLOW /PER AREA VWPS/.  HOWEVER...WITH THE APPROACH OF
THIS SHORTWAVE TROUGH...INCREASED DYNAMIC FORCING FOR ASCENT COUPLED
WITH THIS OROGRAPHIC FORCING WILL RESULT IN AN INCREASE IN SNOW
COVERAGE AND INTENSITY.  MOREOVER...THE PRESENCE OF STEEP MID-LEVEL
LAPSE RATES AND RESULTANT CONVECTIVE INSTABILITY WILL SUPPORT A
CONTINUATION OF EMBEDDED CONVECTIVE ELEMENTS WHICH WILL
SIGNIFICANTLY ENHANCE PRECIPITATION RATES.

EXPECT THE HEAVIEST SNOW RATES /PRIMARILY ABOVE 3000 FT MSL/ TO
BEGIN AROUND 15Z AND CONTINUE THROUGH THE AFTERNOON.  HOURLY SNOW
RATES OF 1-2 INCHES APPEAR LIKELY WITH LOCALIZED BURSTS EXCEEDING 3
INCHES POSSIBLE.

..MEAD.. 03/11/2006

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

ATTN...WFO...GJT...TWC...FGZ...SLC...PSR...VEF...

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