MESO: Mesoscale Discussion 0089

ACUS11 KWNS 271251
SWOMCD
SPC MCD 271251
IDZ000-ORZ000-WAZ000-271815-

MESOSCALE DISCUSSION 0089
NWS STORM PREDICTION CENTER NORMAN OK
0651 AM CST SUN JAN 27 2008

AREAS AFFECTED...OR...WA...ID

CONCERNING...HEAVY SNOW

VALID 271251Z - 271815Z

A PERSISTENT BAND OF LIGHT FREEZING RAIN AND SNOW ACROSS THE
COLUMBIA BASIN IS FORECAST TO GRADUALLY SHIFT SEWD TOWARD NERN ORE
AND NCNTRL ID OVER THE NEXT SEVERAL HOURS. STRONGER LIFT AND
RESULTANT DEEP-LAYER ADIABATIC COOLING SHOULD SUPPORT AREAS OF
POTENTIALLY HEAVY SNOW DEVELOPING LATER THIS MORNING...PRIMARILY
FROM NRN/NERN ORE INTO ID. SNOWFALL RATES ACROSS THESE AREAS COULD
APPROACH 1 INCH PER HOUR AS PRECIPITATION RATES INCREASE.

DEEP-LAYER ASCENT IS FORECAST TO CONTINUE TO STRENGTHEN ACROSS THE
CASCADES AND BLUE MOUNTAINS AS A STRONG SHORT WAVE TROUGH MOVES
TOWARD THE PACIFIC NORTHWEST TODAY. THIS LIFT WILL BE FOCUSED ALONG
A WELL-DEFINED MID LEVEL BAROCLINIC ZONE AND WILL BE FURTHER
ENHANCED BY MID/UPPER LEVEL JET COUPLING BETWEEN THE APPROACHING
SHORT WAVE TROUGH AND THE STRONG LOW MOVING INTO CA. MOISTURE
TRANSPORT INTO THIS ZONE OF ASCENT IS FORECAST TO STRENGTHEN
CONSIDERABLY OVER THE NEXT FEW HOURS AND LEAD TO AN INCREASE IN
PRECIPITATION ACROSS THE REGION.

WHILE POCKETS OF FREEZING RAIN PERSIST IN THE COLUMBIA VALLEY
ATTM...THERMODYNAMIC PROFILES SHOULD BECOME INCREASINGLY SUPPORTIVE
OF SNOW AS THE TROPOSPHERE COMES UNDER THE INFLUENCE OF STRONGER
LIFT AND ADIABATIC COOLING. LATEST HIGH RESOLUTION ARW AND NMM
WRFS...RUC...AND NAM12 ALL INDICATE THAT SNOWFALL RATES COULD
INCREASE TO ABOUT 1 INCH PER HOUR IN SOME LOCATIONS THROUGH 18Z
TODAY.

.CARBIN.. 01/27/2008

..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...MSO...BOI...OTX...PDT...

44821655 44531696 44271850 44461877 44751932 45041992
45301993 45931934 47711709 47811654 46661565 45171624

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@PO.UIUC.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.