FXUS66 KOTX 021014
AFDGEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WASHINGTON
230 AM PST FRI APR 2 2004

.SYNOPSIS...HIGH PRESSURE WILL BRING MOSTLY CLEAR AND MILD
CONDITIONS TO THE REGION THROUGH SATURDAY MORNING. LATE SATURDAY
AND SUNDAY A PACIFIC WEATHER SYSTEM WILL INCREASE THE THREAT
FOR SHOWERS AND A FEW THUNDERSTORMS OVER THE AREA.

&&

.DISCUSSION...
TODAY THROUGH TONIGHT...MAIN SYNOPTIC FEATURES ON SATELLITE WHICH
WILL IMPACT REGIONAL WEATHER IN THE SHORT TERM INCLUDE THE UPPER
LEVEL CUT-OFF LOW SPINNING OVER CALIFORNIA AND NEVADA THIS MORNING.
WHILE THIS LOW IN ITSELF IS NOT A THREAT...THE SOUTHERLY FLOW
AROUND THE EASTERN FLANK OF THIS FEATURE IS FORCING A WELL DEFINED
TONGUE OF SUB-TROPICAL MOISTURE REMINISCENT OF A SUMMER MONSOONAL
PUSH TOWARD THE FORECAST AREA. THE OTHER FEATURES OF INTEREST ARE
A STRONG UPPER LEVEL RIDGE AXIS ALONG 130N...AND THE DEEP UPSTREAM
PACIFIC TROUGH NEAR 150W. LATEST MODEL RUNS ARE QUITE SIMILAR FOR THE
NEXT 24 TO 36 HOURS AND SATELLITE EXTRAPOLATION SUPPORTS MODEL
FORECASTS. FOR TODAY FORECAST AREA WILL BE DOMINATED BY THE UPPER
LEVEL RIDGE HOOKING INTO THE NORTHWEST FROM THE PACIFIC. EXPECT NO
SIGNIFICANT WEATHER WITH MOSTLY CLEAR SKIES AND TEMPERATURES REACHING
WELL ABOVE NORMAL THROUGHOUT THE FORECAST AREA. TONIGHT MOSTLY CLEAR
SKIES WILL PROMOTE RADIATIONAL COOLING BUT BY THEN AN INCREASING
NORTHEASTERLY GRADIENT WILL KEEP VALLEY WINDS UP ENOUGH TO PROMOTE
TURBULENT MIXING NEAR THE SURFACE AND PREVENT LOW TEMPERATURES FROM
REACHING THE FREEZING MARK AT MOST STATIONS.

SATURDAY THROUGH SUNDAY...WEATHER MAY LIVEN UP THIS WEEKEND OVER THE
NORTHWEST AS TWO SYNOPTIC FEATURES BEGIN TO INTERACT. BY LATE
SATURDAY THE DEEP MOISTURE FETCH WORKING IT'S WAY UP FROM THE SOUTH
WILL REACH EASTERN WASHINGTON AND NORTH IDAHO RAISING PRECIPITABLE
WATER VALUES INTO THE .5 TO .8 INCH RANGE. MEANWHILE THE NEXT PACIFIC
TROUGH WILL CLOSE WITH THE COAST AND HURL A SHORT WAVE INTO THE
REGION. ETA AND GFS DIFFER IN THE SPEED AND STRENGTH OF THIS NEXT
SYSTEM. GFS IS SIMILAR TO YESTERDAY'S 00Z RUN WITH THE STRENGTH OF
THE INCOMING WAVE AND ASSOCIATED MID LEVEL COLD FRONT...AND MORE
CONSISTENT WITH PREVIOUS RUNS THAN THE ETA. GFS ALSO INITIALIZES VORT
FEATURES OUT OVER THE PACIFIC WELL AT THIS TIME AND HAS A GOOD GRIP
ON THE UPPER LEVEL MOISTURE PLUME APPROACHING FROM THE SOUTH. THUS
WILL USE GFS FOR THIS SYSTEM. BY SATURDAY AFTERNOON AIR MASS IS
MOISTENED UP WITH THE SOUTHERLY PWAT FETCH. THE PACIFIC SHORT WAVE
WILL INTERACT WITH THIS MOISTURE WITH A WEAK BUT IDENTIFIABLE JET
FEATURE AND ASSOCIATED DIFFERENTIAL PVA CROSSING EASTERN WASHINGTON
AND NORTH IDAHO LATE IN THE DAY AND INTO THE EVENING. WILL ASSUME
MOISTURE AND UPPER LEVEL SUPPORT AVAILABLE FROM THIS INTERACTION.
THE ASSOCIATED MID LEVEL COLD FRONT MOVING THROUGH THE BASIN WILL
PROVIDE A FOCUSING BOUNDARY...ALTHOUGH EXACT TIMING IS STILL
UNCERTAIN. INSTABILITY IS THE MAIN UNCERTAINTY AT THIS TIME...BUT
BOTH MODELS INDICATE AN 850-700MB THERMAL RIDGE OVER THE IDAHO
PANHANDLE DURING THE DAY THUS THE POTENTIAL FOR TEMPERATURES TO
APPROACH 70 DEGREES AT MANY LOWER ELEVATION LOCATIONS. A RELATIVE
MINIMUM dTHETAE/dz AXIS HAS BEEN DEPICTED IN THE GFS FOR THE LAST
FEW RUNS PASSING OVER EASTERN WASHINGTON AND NORTH IDAHO DURING THE
NIGHT. THUS POTENTIAL EXISTS FOR THUNDERSTORMS OVER THE EASTERN ZONES
LATE SATURDAY AND SATURDAY NIGHT WHERE ALL THESE INGREDIENTS MERGE.
ON SUNDAY POST FRONTAL AIR MASS WITH WESTERLY MID LEVEL FLOW WILL
RETURN WEATHER TO MORE OF AN OROGRAPHIC SHOWER REGIME. SATURDAY
NIGHT'S SURFACE COLD FRONT WILL BE QUITE WEAK AND WILL NOT
HAVE MUCH OF A COOLING EFFECT ON SUNDAY'S HIGH TEMPERATURES. /FUGAZZI

SUNDAY NIGHT THROUGH THURSDAY...NEW GFS RUN THIS MORNING IN LINE
BETTER WITH THE EURO COMPARED TO LAST NIGHT'S SOLUTION. ALL MODELS
NOW HAVE A GOOD AGREEMENT WITH KEEPING A MEAN RIDGE ACROSS THE
REGION SUNDAY NIGHT INTO THURSDAY. THE GFS HAS A FEW VERY SMALL WAVES
MOVING THROUGH THE RIDGE BOTH MONDAY AND THURSDAY...BUT WILL LEAVE
OUT ANY MENTION OF PRECIPITATION FOR NOW BECAUSE OF UNCERTAINTY. IT
WILL BE MOST LIKELY A BIT ABOVE NORMAL FOR TEMPERATURES DURING THE
EXTENDED PERIOD UNDER THE RIDGE WITH CONTINUED BELOW NORMAL
PRECIPITATION. /TC


&&

.PRELIMINARY POINT TEMPS/POPS...

SPOKANE        061 035 067 037 067/ 00 00 20 20 10
COEUR D'ALENE  060 036 068 038 068/ 00 00 20 20 20
PULLMAN        059 035 066 038 066/ 00 00 20 20 20
LEWISTON       064 038 073 042 073/ 00 00 05 20 20
COLVILLE       060 033 067 038 065/ 00 00 20 20 20
SANDPOINT      057 031 068 035 067/ 00 00 20 20 20
WALLACE        051 032 063 036 063/ 00 00 20 20 20
MOSES LAKE     066 035 070 038 068/ 00 00 05 05 05
WENATCHEE      067 036 069 040 067/ 00 00 05 05 10
OMAK           063 033 073 036 071/ 00 00 05 05 10
&&

.OTX...
ID...NONE.
WA...NONE.


$$