MOJAVE DESERT/SOUTHERN GREAT BASIN AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
AFDLAS 927 AM PST MON JAN 7 2002
SYNOPSIS...VARIABLE CLOUDINESS WILL CONTINUE OVER THE REGION TODAY
AND TUESDAY AS A BROAD BAND OF MID AND HIGH LEVEL MOISTURE STREAMS
INLAND IN ADVANCE OF A DEVELOPING STORM ALONG THE CALIFORNIA COAST.
TEMPERATURES WILL REMAIN SEASONABLY MILD THROUGH WEDNESDAY.
DISCUSSION...12Z AVN CONTINUES TO DEPICT A CLOSED LOW FORMING
OFFSHORE IN THE SOUTHERN STREAM WEDNESDAY. THE ETA IS SLIGHTLY
SLOWER ON THE DEVELOPMENT OF AN UPPER LOW AND IT PREDICTS MORE OF AN
INLAND TRACK BRINGING THE COLD CORE ACROSS SOUTHERN CALIFORNIA LATE
WEDNESDAY. THE PRIMARY CAUSE FOR THE DIFFERENCE APPEARS TO BE IN THE
WAY THE TWO MODELS HANDLE THE SOUTHERN STREAM JETSTREAK UPSTREAM
FROM THE TROUGH AXIS. THE AVN INDICATES A STRONGER MORE NORTHERLY
JET DIVING INTO A SHARPER TROUGH AXIS. THE ETA HAS A LOWER AMPLITUDE
WITH A WEAKER NW JETSTREAK UPSTREAM. BOTH ETA AND AVN INITIALIZED
WELL THOUGH. OVERLAYING 200-300MB HEIGHTS AND WINDSPEEDS WITH WATER
VAPOR IMAGERY AND AIRCRAFT REPORTS DOESN'T REALLY SHOW ANY OBVIOUS
DIFFERENCES BETWEEN THEM. HOWEVER THE SOUTHERN STREAM HAS SHOWN
SIGNIFICANT AMPLIFICATION ASSOCIATED WITH THE COLD LOW EVIDENT NEAR
42N/138W. THIS WOULD SEEM TO FAVOR THE AVN SOLUTION. IN THE ABSENCE
OF A SUBTROPICAL FETCH THAT TRACK IS TOO FAR OFFSHORE TO PRODUCE A
SERIOUS PRECIP THREAT FOR SOUTHERN NEVADA. NO UPDATES FOR NOW.
RUNK
.LAS...NONE.
EASTERN WASHINGTON AND NORTH IDAHO AREA FORECAST DISCUSSION
NWS SPOKANE WASHINGTON
AFDGEG 900 AM PST MON JAN 7 2002
FREEZING LEVELS HIGHER THIS MORNING PER EARLY MORNING SOUNDING AND
RECENT ACARS SOUNDING FROM GEG...GENERALLY 8000 TO 9000 FT. MULLAN
PASS CONTINUES TO REPORT LIGHT RAIN WITH AVAILABLE MORNING SKI
REPORTS INDICATING TEMPERATURES IN THE MID 30S AT THE SUMMITS.
FURTHER WEST...COLD AIR SLOW TO SCOUR OUT. RAIN HAS NOW BEEN REPORTED
IN THE WINTHROP VICINITY WITH 32F AND LARGE WET SNOWFLAKES FALLING
NEAR MAZAMA. WILL BE HOLDING ONTO THE WINTER WEATHER ADVISORY THROUGH
EXPIRATION AND MAKE ADJUSTMENTS AS NEEDED AS WARMER AIR SLOWLY WORKS
FURTHER UP THE VALLEYS.
DEEP UPPER TROUGH ALONG 140W BRINGING DEEP MOISTURE WITH UPPER JET
EXPECTED TO CROSS THROUGH THE FORECAST AREA TONIGHT. TEMPORARY BREAK
IN THE RAIN ACROSS SPOKANE AREA...HOWEVER NEXT ROUND OF RAIN IS
EXPANDING ACROSS SOUTHEAST WA AND WILL FILL IN ACROSS THE PALOUSE AND
LEWISTON AREA NEXT FEW HOURS. MILD TEMPERATURES TODAY WITH 40S EAST
AND EVENTUALLY UPPER 30S IN THE EAST CASCADE VALLEYS. EVEN COOL SPOTS
IN THE UPPER COLUMBIA BASIN WILL SEE SIGNIFICANT TEMPERATURE JUMPS
LATER THIS MORNING AS SHALLOW COLD AIR IS MIXED OUT BY INCREASING LOW
LEVEL WINDS. SERVICE HYDROLOGIST IS ON STATION AND IS KEEPING TABS ON
LOCAL STREAMS AND RIVERS. JR
...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 045/040/042/032/038 +8410
COE 043/038/041/030/039 +8410
PUW 047/040/043/032/040 +8410
LWS 051/041/048/035/043 77510
CQV 042/037/040/030/037 +8630
SPT 040/034/039/030/038 +8630
WWP 040/036/039/031/037 +9740
EAT 038/034/040/031/036 75310
MWH 045/038/044/032/039 75310
.OTX...WINTER WEATHER ADVISORY FOR SNOW THIS MORNING FOR WA ZONE 42.
.HYDROLOGICAL OUTLOOK THROUGH TUESDAY FOR MOST OF EASTERN WA
AND NORTH IDAHO.