[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 200130
SWOMCD
SPC MCD 200130 
WAZ000-ORZ000-200630-

MESOSCALE DISCUSSION 2584
NWS STORM PREDICTION CENTER NORMAN OK
0730 PM CST MON DEC 19 2005

AREAS AFFECTED...NERN ORE/ERN WA

CONCERNING...PRECIPITATION TRENDS...WINTER PRECIPITATION 

VALID 200130Z - 200630Z

FREEZING RAIN WILL CONTINUE TO DEVELOP OVER THE WRN COLUMBIA RIVER
BASIN/GORGE OF NRN ORE THROUGH 03Z. FREEZING RAIN WILL EVENTUALLY
DEVELOP INTO THE ERN SLOPES OF THE CASCADES AND COLUMBIA RIVER BASIN
OF ERN WA BETWEEN 03-06Z. A COUPLE HOUR PERIOD OF HRLY PRECIP RATES
UP TO 0.05 INCH WILL BE POSSIBLE...ESPECIALLY WITHIN 1-2 HOURS OF
ONSET OF PRECIPITATION.

AN AREA OF MOD-OCCASIONALLY HEAVY PRECIPITATION OVER NWRN ORE HAS
DEVELOPED IN AN AREA OF MODERATE WAA AHEAD OF DEEP UPPER CYCLONE
WELL OFF THE ORE COAST. THIS PRECIPITATION WILL CONTINUE TO SPREAD
NEWD INTO THE COLUMBIA RIVER BASIN THROUGH THE LATE EVENING HOURS ON
THE HEAL OF A 50-60 KT LOW LEVEL SSWLY JET. RECENT SURFACE
OBSERVATIONS INDICATE HRLY RAINFALL RATES UP TO 0.2O INCH OVER THE
NRN WILLAMETTE VALLEY. ALTHOUGH LOW LEVEL FLOW WILL REMAIN SSWLY
WHICH SHOULD AID IN SOME SUBSIDENCE ON THE LEE-SIDE OF THE
CASCADES...AND THUS LOWER HRLY PRECIP AMOUNTS...SUFFICIENTLY DEEP
VERTICAL MOTION SHOULD ALLOW FOR LIGHT TO OCCASIONALLY MODERATE
FREEZING RAIN TO DEVELOP INTO THE SERN SLOPES OF THE WA CASCADES AND
COLUMBIA RIVER BASIN OF WA BETWEEN 03-06Z.

FURTHER SOUTH...AS THE BULK OF THE LOW LEVEL LIFT/PRECIP CONTINUES
TO MOVE NWD...EXPECT A DIMINISHING OF THE FREEZING RAIN RATES OVER
THE DESCHUTES VALLEY THROUGH 06Z.

..CROSBIE.. 12/20/2005

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

ATTN...WFO...OTX...PDT...PQR...

47211981 47692030 47472102 47142094 46002160 45532231
45032185 44682168 44632070 44672056 45421981 46461970 

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