Heavy Snow in Idaho, December 6, 2001

EASTERN WASHINGTON AND NORTH IDAHO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WASHINGTON
230 AM PST THU DEC 6 2001

HIGHLIGHTS WILL STAY AS IS AS THE SNOW IS ALREADY UNDERWAY ACROSS
EASTERN WASHINGTON. WARM ADVECTION APPEARS TO BE DRIVING MUCH OF THE
PRECIPITATION PRODUCTION...HOWEVER TROUGH HAS FRACTURED A BIT WHILE
TAKING ON A BIT OF NEGATIVE TILT...LIKELY TO KEEP SOME ENHANCEMENT
ACROSS THE NORTHERN MOUNTAINS INTO THE IDAHO PANHANDLE THROUGH
MORNING. SURFACE TROUGH HAS CROSSED THROUGH THE CASCADES WITH
WESTERLY FLOW NOW MOVING THROUGH STAMPEDE PASS. SNOW INTENSITY SHOULD
DROP OVER THE NEXT FEW HOURS ALONG THE EAST SLOPES AND
BASIN...KEEPING ACCUMULATIONS BELOW ADVISORY CRITERIA. EXPECT PARTIAL
CLEARING AND LOCALLY BREEZY CONDITIONS BY AFTERNOON...ALTHOUGH 06Z
ETA HAS BACKED OFF A BIT ON 850 MB WIND SPEEDS. AVN SEEMS TO INSIST
ON WEST-NORTHWEST FLOW ONTO THE CAMAS PRAIRIE LATE THIS AFTERNOON AND
EVENING AS THE ATMOSPHERE BECOMES MORE CONVECTIVE UNDER THE -29C 500
MB THERMAL TROUGH...WHILE ETA DOES NOT. ETA APPEARS TO INDICATE
BETTER LOW LEVEL TROUGHING IN THE LEE OF THE CASCADES AS WESTERLIES
INCREASE ALOFT...KEEPING LOW LEVEL WINDS MORE WEST-SOUTHWESTERLY.
SNOW LEVELS RISE AS WARMER AIR WORKS NORTHEASTWARD...ALLOWING FOR
PRECIPITATION TO DECREASE TO MAINLY RAIN SHOWERS BELOW 3000 FEET WITH
SNOW SHOWERS CONTINUING IN THE MOUNTAINS.

UPPER JET SHIFTS NORTH AND MID-LEVEL RIDGING BUILDS NORTHWARD. A FEW
RIPPLES WILL BRUSH NORTHERN ZONES ALLOWING FOR CHANCES OF MOUNTAIN
SNOW AND LOWER VALLEY RAIN SHOWERS. IN THE BASIN...LIGHT WINDS AND A
STRONG INVERSION MAY ALLOW FOR FOG...AND MAY ADD A MENTION PATCHY FOG
FOR FRIDAY NIGHT. NEXT SYSTEM BRINGS PRECIPITATION BACK INTO THE
REGION LATER SATURDAY...AND SHOULD SEE MORE RAIN AS PRECIPITATION
TYPE IN THE VALLEYS THAN WITH PREVIOUS SYSTEMS.  JR

.EXTENDED...STILL MORE WAVES IN STORE FOR THE EXTENDED PERIOD.  AS
USUAL TIMING IS DIFFICULT.  ALTHOUGH THERE WILL BE SOME SHORT PERIODS
OF DRY WEATHER THERE WILL BE SOME PRECIPITATION IN EACH 24 HOUR
PERIOD FROM SUNDAY THROUGH WEDNESDAY. PRESENT FORECASTS CALL FOR A
CHANCE OF MOUNTAIN SNOW AND VALLEY RAIN AND THIS WILL BE CONTINUED.
LH

...THE INFORMATION IN THIS PRODUCT CONCERNING WARNINGS AND FORECASTS
IS VALID ONLY AT THE TIME OF ISSUANCE. THE LATEST WARNING AND
FORECAST INFORMATION WILL BE FOUND IN THE APPROPRIATE PRODUCTS...

GEG 037/029/039/029/039 94114
COE 036/026/036/028/038 95224
PUW 038/030/039/029/040 94114
LWS 044/035/047/037/048 94122
CQV 038/029/040/029/039 95334
SPT 034/028/037/029/038 96555
WWP 034/027/036/029/037 97645
EAT 040/031/040/031/038 61114
MWH 041/032/041/031/040 71114

.OTX...WINTER STORM WARNING FOR WA ZONE 31 TODAY.
    ...WINTER STORM WARNING SNOW IDAHO ZONE 4 TODAY THROUGH TONIGHT.
    ...WINTER STORM WARNING ID ZONE 1 AND WA ZONES 37 38 THROUGH
       THIS AFTERNOON.
    ...WINTER WEATHER ADVISORY FOR SNOW ID ZONES 2 3 AND WA ZONES
       33 36 THROUGH THIS AFTERNOON.
    ...WINTER WEATHER ADVISORY ID ZONE 27 TODAY THROUGH THIS EVENING.