Heavy Snow in Idaho, February 28, 2002

EASTERN WASHINGTON AND NORTH IDAHO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WASHINGTON
230 AM PST THU FEB 28 2002

THE ONLY INTERESTING WEATHER IN THE SHORT TERM IS WHAT IS HAPPENING
TONIGHT. A COLD FRONT MOVED SOUTHWARD ACROSS THE AREA TODAY AND THIS
IS FOLLOWED BY A VERY COLD POOL OF AIR ALOFT. NORTHWEST FLOW ALOFT
WILL CARRY THIS POOL SOUTHEASTWARD AND MAINLY AFFECT THE CENTRAL
PANHANDLE MOUNTAINS AND THE CAMAS PRAIRIE AREA. THIS WILL BE EARLY
THIS MORNING AND SHOULD BE ABOUT OVER WITH NEAR SUNRISE. ONLY ONE
REPORT OF SNOW IN THE 2 TO 4 INCH RANGE WAS RECEIVED AND THIS FROM
NEAR THE CANADIAN BORDER. OTHER REPORTS WERE TRACES OF PRECIPITATION
WITH ONLY A FEW TENTHS OF SNOW DEPTH. SATELLITE PICTURES SHOW
DECREASING CLOUDS MOVING INTO THE AREA FROM THE NORTH AND WHAT CLOUDS
ARE REPORTED OVER THE CWA ARE HIGHER LEVEL.  A MUCH WEAKER WAVE
MOVING SOUTHWARD WILL REACH THE IDAHO PANHANDLE FRIDAY MORNING. LOOKS
TOO WEAK TO BRING ANYTHING AND PRESENT FORECAST FOLLOW THIS TREND.
LARGE RIDGE WITH AXIS JUST OFF THE WEST COAST TO MAINTAIN DRY
CONDITIONS THROUGH SATURDAY.  PERSISTENCE SEEMS THE BEST WAY TO GO
WITH THE TEMPERATURES.  LOTS OF OVERNIGHT LOW TEMPERATURES IN THE
TEENS WITH LOCAL SINGLE DIGIT READINGS OVER EASTERN WASHINGTON AND
THE IDAHO PANHANDLE. SLIGHTLY COOLER FRIDAY NIGHT. WILL DROP THE
ADVISORY FOR THE CENTRAL IDAHO MOUNTAINS WITH THE MORNING PACKAGE.
BEST CHANCE OF SNOW WILL BE OVER IDAHO ZONE 27...CAMAS PRAIRIE...AND
SO WILL KEEP THIS ADVISORY THROUGH TODAY AND LET THE DAY SHIFT SEE
WHAT KIND OF REPORTS THEY RECEIVE. LH

EXTENDED...THE LATEST MRF IS COMING IN LINE NICELY WITH THE PREVIOUS
RUN AND THE ENSEMBLE MEAN FROM 2 DAYS AGO. WHAT THIS AMOUNTS TO IS A
SIGNIFICANT PATTERN CHANGE WITH THE MEAN RIDGE OFF THE COAST...BEING
REPLACED BY A MUCH STRONGER ONE NEAR 160W. THIS PLACES THE WEST COAST
UNDER THE INFLUENCE OF STRONG NORTHERLY FLOW EMANATING FROM THE HEART
OF THE YUKON AND THE WESTERN PORTION OF THE NORTHWEST TERRITORIES. A
STRONG SHORTWAVE TROF IS EXPECTED TO RIDE DOWN THIS FLOW LATE SUNDAY
AND INTO MONDAY DRIVING YET ANOTHER ARCTIC BOUNDARY INTO THE INLAND
NW. POSITIONING OF THIS FRONT PER THE LATEST MRF IS NEAR THE CANADIAN
BORDER ON MONDAY AND THROUGH THE ENTIRE CWA BY TUESDAY. THIS IS A
SIGNIFICANT CHANGE FROM YESTERDAYS RUN WHICH KEPT THIS ARCTIC AIR
BOTTLED NORTH OF THE INTERNATIONAL BORDER...BUT IT SEEMS LOGICAL WITH
THE SURFACE-850 MB LOW NOW DIVING SOUTH OF THE OLYMPIC PENINSULA.
THIS NOTION IS ALSO SUPPORTED BY THE CANADIAN MODEL. PRECIPITATION
CHANCES WILL BE CLOSELY TIED TO THE POSITIONING OF THE FRONT. ONCE
THE FRONT PUSHES THROUGH...WE WILL BE SUBJECT TO A COLD SHOWERY
REGIME AS THE UPPER LEVEL PATTERN STALLS WITH A LONGWAVE TROF
EXTENDING FROM THE WESTERN PORTION OF THE HUDSON BAY VORTEX TOWARD
THE PAC NW. TEMPS WILL LIKELY BE ABOUT 10-15 DEGREES COOLER THAN
NORMAL ON TUESDAY AND WEDNESDAY(AND BEYOND)WITH 850MB TEMPS OF -10C
OR COLDER ADVERTISED. THIS IS SLIGHTLY COOLER THAN THE CURRENT BATCH
OF ARCTIC AIR...HOWEVER IT SHOULD BE TEMPERED BY THE EVER INCREASING
SOLAR INPUT. CONSEQUENTLY WE WILL KEEP HIGHS GENERALLY IN THE 30S
...BUT NIGHTTIME LOWS COULD EASILY DIP INTO THE SINGLE DIGITS OVER
SNOW COVERED AREAS.

FX

...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 034/017/033/013/032 10111
COE 033/017/033/013/032 10111
PUW 034/018/034/015/032 20111
LWS 039/024/036/018/039 20111
CQV 034/016/034/011/033 10111
SPT 033/017/033/013/033 10111
WWP 032/016/032/013/032 21112
EAT 044/023/041/019/040 00100
MWH 042/020/038/017/040 00100

.OTX...WINTER WEATHER ADVISORY FOR SNOW TODAY IDZ027 (CAMAS PRAIRIE).