[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 311832
SWOMCD
SPC MCD 311832 
CAZ000-312330-

MESOSCALE DISCUSSION 2605
NWS STORM PREDICTION CENTER NORMAN OK
1232 PM CST SAT DEC 31 2005

AREAS AFFECTED...SIERRA MOUNTAINS

CONCERNING...HEAVY SNOW 

VALID 311832Z - 312330Z

HEAVY WET SNOW WILL CONTINUE/SPREAD SOUTHWARD ACROSS THE HIGHER
ELEVATIONS OF THE SOUTHERN SIERRA MOUNTAINS THROUGH THE AFTERNOON.
SNOW RATES OF 2-3 IN/HR WILL BE POSSIBLE...NAMELY ABOVE 7000-7500
FT.

WATER VAPOR IMAGERY PORTRAYS COMPACT SHORTWAVE TROUGH/VORTICITY
MAXIMA MOVING EASTWARD ALONG THE NORTHERN CA COAST. MESONET
OBSERVATIONS GENERALLY INDICATE SNOW LEVELS AROUND 6000-6500 FT
ACROSS THE NORTHERN SIERRAS /NORTH 0F I-80/...WITH 7000-7500 FT OR
HIGHER SNOW LEVELS PROGRESSIVELY SOUTHWARD ACROSS THE
CENTRAL/SOUTHERN SIERRAS. SNOW LEVELS SHOULD INITIALLY REMAIN
RELATIVELY STEADY STATE ACROSS THE SOUTHERN SIERRAS ATTRIBUTABLE TO
MODEST WARM AIR ADVECTION...BUT BEGIN LOWERING BY MID/LATE AFTERNOON
AS CORE OF UPPER TROUGH/COLD POCKET TRANSITIONS EASTWARD. IN
PRESENCE OF DPVA/STRONG OROGRAPHIC FORCING AND STEEPENING LAPSE
RATES/CONVECTIVE ENHANCEMENT...HIGH PRECIPITABLE WATER ENVIRONMENT
/1.23 PW PER SPECIAL 15Z OAKLAND ROAB -- 200+ PERCENT OF NORMAL/
WILL CONTRIBUTE TO HEAVY WET SNOW RATES OF 2-3 IN/HR OR
GREATER...ESPECIALLY FOR W/SW FACING SLOPES OF THE SOUTHERN SIERRAS
INTO EARLY EVENING.

..GUYER.. 12/31/2005

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

ATTN...WFO...VEF...REV...HNX...STO...

36661900 37351957 38552055 39292095 39342033 38401944
37341858 36751833 36261818 36191832 36251869 36351883 

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