Heavy Snow in Washington, March 17, 2002

EASTERN WASHINGTON AND NORTH IDAHO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WASHINGTON
230 AM PST SUN MAR 17 2002

THE UPPER LEVEL LOW THAT HAS BEEN WITH US FOR THE LAST FEW DAYS IS
NOW CENTERED OVER WEST CENTRAL WASHINGTON. DUE TO THE PROXIMITY OF
THE UPPER LEVEL COLD CORE NUMEROUS SHOWERS CONTINUE TO DEVELOP OVER
EASTERN WASHINGTON AND NORTH IDAHO THIS MORNING. SOME OF THESE
SHOWERS HAVE PRODUCED MODERATE TO HEAVY SNOW WITH LOCAL ACCUMULATIONS
OF SEVERAL INCHES. THESE SHOWERS...HEAVY AT TIMES...WILL CONTINUE
THROUGH THE MORNING HOURS BEFORE TAPERING OFF THIS AFTERNOON.
THEREFORE...WILL EXTEND THE WINTER STORM WARNING FOR THE NORTHERN
ZONES THROUGH THIS AFTERNOON. ALSO WILL KEEP THE CURRENT WINTER
WEATHER ADVISORIES FOR SNOW GOING THROUGH THE AFTERNOON FOR THE
CASCADE EAST SLOPES...SPOKANE/COEUR DALENE AREAS AND THE CENTRAL
PANHANDLE MOUNTAINS...BUT WILL ALSO ADD THE PALOUSE AS SIGNIFICANT
SHOWERS CONTINUE TO MOVE ACROSS THAT AREA AT THIS TIME. THE LOW
PRESSURE SYSTEM IS FORECAST TO FINALLY MOVE SOUTHEAST OF THE CWA AND
WEAKEN THIS EVENING ALLOWING DRIER...MORE STABLE...NORTHWESTERLY FLOW
TO SET UP. THUS EXPECT SNOW SHOWERS TO DECREASE THIS AFTERNOON THEN
FINALLY TAPER OFF THIS EVENING. COLD ARCTIC AIR OVER SOUTHERN B.C. IS
SLOWING SEEPING INTO THE REGION THROUGH THE OKANOGAN VALLEY AND THE
PURCELL TRENCH THIS MORNING. THIS IS NOT AN EXTREME ARCTIC PUSH AND
EXPECT THE COLD AIR WILL NOT MAKE IT MUCH FURTHER SOUTH THAN THE
NORTHERN TWO-THIRDS OF WASHINGTON AND THE NORTH IDAHO PANHANDLE...BUT
WILL KEEP TEMPERATURES WELL BELOW NORMAL FOR THIS TIME OF YEAR. THIS
DRIER COLD PATTERN WILL LAST THROUGH MONDAY...BUT GIVE WAY TO A
PACIFIC TROUGH SPREADING PRECIPITATION OVER THE REGION ONCE AGAIN ON
MONDAY NIGHT AND TUESDAY. CC

.EXTENDED (WED THRU SAT) - BIG DIFFERENCES IN THE EXTENDED FCST
MODELS, WITH THE MRF AND ECMWF MOVG THE E/W UPPER TROF AXIS TO NR THE
SRN PART OF BC WED, IN RESPONSE TO A FARTHER EWD PROGRESSION OF THE
CLOSED LOW NR 40N 140W. THE MRF MAKES THIS REX-TYPE FEATURE IN THE
EPAC SO DOMINANT THAT THE CLOSED LOW SLOWLY MOVES TO NR 130W BY FRI,
LIFTING WEDS STALLING FRONTAL BOUNDARY NWD AS A WARM FRONT THURS.
THIS IN TURN PRODUCES UPPER RIDGING FOR LATE THURS AND MUCH OF FRI
WITH A WARMING AND DRYING TREND. THE CANADIAN IS FARTHER W WITH THIS
CLOSED LOW, ALLOWING THE BC TROF TO MOV SEWD THRU THE PAC NW THRU
SAT, EFFECTIVELY KEEPING MUCH OF THE W COAST MUCH COOLER AND UNDER
THE THREAT OF SHOWERS. THE CANADIAN HAS BEEN MORE CONSISTENT LATELY,
WITH WILD SWINGS IN THE MRF/AVN. SO, WL OPT TO GO WITH A COMBO
BETWEEN THE LATEST MRF ENSEMBLE MEAN AND THE CANADIAN, AND KEEP
SHOWERS IN THE FCST THRU SAT...AND NOT PRODUCE A BIG DRYING AND
WARMING TREND PER THE MRF BEGINNING THURS. WED LOOKS TO BE THE BEST
CHANCE FOR PRECIP (ESPECIALLY N ID) GIVEN MOIST WLY FLOW.

...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 033/017/035/023/036 83375
COE 032/014/033/021/035 84375
PUW 035/019/036/026/038 84365
LWS 038/024/040/030/041 54265
CQV 032/013/034/024/036 83486
SPT 027/011/029/020/033 83586
WWP 031/016/032/023/035 85487
EAT 038/024/039/027/042 62363
MWH 038/026/041/029/045 63264

.OTX...WINTER STORM WARNING THROUGH THIS AFTERNOON FOR ID ZONE 1 AND
        WA ZONES 37 38 43
       WINTER WEATHER ADVISORY FOR SNOW THROUGH THIS AFTERNOON FOR
        ID ZONES 2 3 4 AND WA ZONES 33 36 42

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SPOKANE, WA
1012 PM PST SAT MAR 16 2002

TIME(PST)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

1250 PM    2 S MALLOTT               WA   HEAVY SNOWFALL
03/16/02   OKANOGAN                       6 INCHES NEW SNOW SINCE
                                          MIDNIGHT AT 2800 FEET

0925 AM    REPUBLIC                  WA   HEAVY SNOWFALL
03/16/02   FERRY                          4 1/2 INCHES OF SNOW FROM
                                          6-9 AM.

0155 PM    15 W OKANOGAN             WA   HEAVY SNOWFALL
03/16/02   OKANOGAN                       7 INCHES OF SNOW SINCE
                                          MIDNIGHT

0600 PM    21 E OMAK                 WA   HEAVY SNOWFALL
03/16/02   OKANOGAN                       15 INCHES OF SNOW
                                          CONSERVATIVELY ESTIMATED AT
                                          THE MOSES MTN SNOTEL SITE
                                          IN PST 24 HOURS...ELEV 5300
                                          FEET

AH