AREA FORECAST DISCUSSION

 
 FXUS66 KOTX 101037
 AFDOTX
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE SPOKANE WA
 237 AM PST WED FEB 10 2010
 
 .SYNOPSIS...WEAK HIGH PRESSURE OVER THE NORTHWEST WILL MAINTAIN
 DRY WEATHER THIS MORNING. A STORM SYSTEM WILL SPREAD A CHANCE OF
 VALLEY RAIN AND SNOW MIX AND MOUNTAIN SNOW OVER THE REGION THIS
 AFTERNOON AND TONIGHT. THIS WILL BE FOLLOWED BY A SERIES OF STORM
 SYSTEMS THAT WILL BRING MOUNTAIN SNOW AND VALLEY RAIN TO THE
 NORTHWEST THROUGH EARLY NEXT WEEK.
 
 
 &&
 
 .DISCUSSION...
 TODAY AND TONIGHT...HIGH PRESSURE IS BUILDING INTO THE REGION
 EARLY THIS MORNING AHEAD OF THE NEXT UP STREAM WEATHER SYSTEM
 WHICH WILL MOVE INSIDE 130W BY SUNRISE. THERE ARE SOME TIMING
 DIFFERENCES WITH THE MODELS AND IT SEEMS THE CONSENSUS HAS BEEN TO
 FOLLOW THE SLIGHTLY SLOWER SOLUTION OF THE NAM/ECMWF COMPARED TO
 THE FASTER GFS AND THIS IS ACCEPTABLE. ALL THE MODELS SHOW THE
 WAVE BENDING DOWN THE RIDGE THIS AFTERNOON WITH THE WEAK COLD
 FRONT MOVING FROM WEST TO EAST AFTER 00-03Z THIS EVENING AND EAST
 OF THE FORECAST AREA BY 12Z TONIGHT.
 
 THE MID LEVEL STRATUS DECK REMAINS EAST OF THE CASCADES THIS
 MORNING...ALTHOUGH THERE HAVE BEEN SOME BREAKS IN THE OVERCAST
 THROUGH THE NIGHT INCREASED MOISTURE MOVING INTO THE REGION WILL
 KEEP MOSTLY OVERCAST SKIES IN THE FORECAST. EXPECT THE WARM OVER
 RUNNING PRECIPITATION TO BE ALONG THE CASCADES BETWEEN 18-21Z AND
 MOVE EAST ACROSS THE FORECAST AREA THROUGH THE REMAINDER OF THE
 AFTERNOON AND EARLY EVENING. SOUTH-SOUTHWEST WINDS AND GOOD UP
 GLIDE SHOULD KEEP THE FOCUS OF THE BEST PRECIPITATION ACROSS THE
 NORTHERN ZONES MAINLY NORTH OF I-90 LATE THIS AFTERNOON AND EARLY
 THIS EVENING. THE LOWER EAST SLOPES AND DEEP BASIN SHOULD GET
 SHADOWED BY THE CASCADES. WITH THE SPEED OF THIS SYSTEM WE DO
 NOT ANTICIPATE A LOT OF PRECIPITATION. SO A HIGH POP LOW QPF
 SYSTEM. AS THE FRONT COMES THROUGH THIS EVENING THE FOCUS OF THE
 PRECIPITATION SHIFTS TO THE EAST AND FINALLY TO THE SOUTHEAST.
 PRECIPITATION AMOUNTS EAST OF A LINE FROM ABOUT WALLA TO COLVILLE
 COULD PICK UP BETWEEN .05 AND .10 OF AN INCH...WITH UP TO .15 FOR
 THE PANHANDLE MOUNTAINS.
 
 SNOW LEVELS START OUT BETWEEN 3000-3500 FEET TODAY AND DROP TO
 AROUND 2500 FEET BEHIND THE FRONT THIS EVENING. PRECIPITATION
 SHOULD BE MAINLY AS SNOW IN THE MOUNTAINS...RAIN IN THE BASIN AND
 A RAIN SNOW MIX ELSEWHERE. ELEVATIONS ABOVE 3000 FEET COULD SEE
 1-3 INCHES BY TONIGHT...WITH UP TO AN INCH OF WET SNOW POSSIBLE
 DOWN TO 2500 FEET. TEMPERATURES AGAIN TODAY WILL BE ON THE WARM
 SIDE OF NORMAL. /TOBIN
 
 THURSDAY THROUGH FRIDAY NIGHT...THE INLAND NORTHWEST WILL EXPERIENCE 
 A PERIOD OF UNSETTLED WEATHER AS A SERIES OF SHORTWAVE TROUGHS 
 ROTATE AROUND THE PARENT UPPER LEVEL LOW RESIDING IN THE GULF OF 
 ALASKA. THERE ARE SOME MODEL TIMING DIFFERENCES WITH THE LATEST GFS 
 GUIDANCE ABOUT 6 TO 12 HOURS FASTER THAN THE NAM AND ECMWF 
 SOLUTIONS. THE FORECAST WILL CONTINUE TO TREND TOWARD THE SLOWER 
 NAM/EC CONSENSUS. 
 
 POPS WILL INCREASE ON THURSDAY AS THE RIDGE AXIS IS PUSHED EAST BY 
 AN ADVANCING PACIFIC TROUGH. PRECIPITATION CHANCES WILL BE HIGHEST 
 THURSDAY NIGHT AS A TROWEL FEATURE...EVIDENT AS A 700MB THETA-E 
 RIDGE...WILL MOVE ACROSS THE FORECAST AREA. PERSISTENT SOUTHERLY 
 FLOW WILL KEEP SNOW LEVELS ABOVE THE VALLEY FLOORS EXCEPT ACROSS THE 
 FAR NORTH WHERE 850MB TEMPS ARE FORECAST TO START OUT AROUND -3C 
 THURSDAY MORNING THEN SLOWLY RISE DURING THE DAY. WHILE SOME OF THE 
 NORTHERN VALLEYS WILL SEE SOME SNOW FALL...ACCUMULATIONS ARE 
 EXPECTED TO BE LIGHT. SOUTHERLY FLOW WILL ALSO ADD OROGRAPHIC LIFT 
 TO ENHANCE PRECIPITATION ACROSS THE NORTHEAST MOUNTAINS THROUGH 
 FRIDAY. A SECOND SHORTWAVE WILL AFFECT THE REGION FRIDAY NIGHT
 INTO SATURDAY WITH ANOTHER ROUND OF VALLEY RAIN AND MOUNTAIN
 SNOW. A STEADY S/SW FLOW REGIME WILL KEEP TEMPERATURES ABOVE
 NORMAL WITH SNOW LEVELS GENERALLY NEAR 3K FT NORTH TO 5K FT SOUTH.
 
 SATURDAY THROUGH TUESDAY...THE ACTIVE WEATHER PATTERN WILL CONTINUE 
 THROUGH THE WEEKEND WITH ANOTHER PACIFIC TROUGH AFFECTING THE REGION 
 ON SUNDAY. THE RIDGE REBOUNDS BY THE START OF THE WORK WEEK BUT 
 MOISTURE WILL CONTINUE TO MOVE THROUGH THE RIDGE. /KELCH
 
 
 &&
 
 .AVIATION...
 VFR CONDITIONS WILL PREVAIL THIS MORNING UNDER A WEAK RIDGE. AN
 INVERSION NEAR 5-7KFT WILL HELP HOLD A DECK IN PLACE OVER MUCH OF
 THE REGION THROUGH THIS MORNING...WITH THE THE POTENTIAL FOR SOME
 BREAK UP THIS AFTERNOON. A WEATHER SYSTEM WILL SWING IN FROM THE WEST
 THIS AFTERNOON AND TONIGHT. THIS WILL RESULT IN LOWERING CLOUDS
 AND INCREASING CHANCES FOR RAIN AFTER 21Z IN THE WEST AND AFTER
 00Z IN THE EAST. MVFR/LCL IFR CIGS ARE POSSIBLE AFTER 01-03Z THIS
 EVENING. /TOBIN
 
 
 
 &&
 
 .PRELIMINARY POINT TEMPS/POPS...
 SPOKANE        42  32  42  35  46  35 /  20  50  50  70  40  60 
 COEUR D`ALENE  41  31  42  34  45  33 /  20  60  50  70  60  60 
 PULLMAN        43  33  45  36  48  36 /  10  60  50  50  40  50 
 LEWISTON       48  37  49  39  53  38 /  10  50  30  30  20  50 
 COLVILLE       40  31  41  34  44  33 /  50  40  50  70  60  60 
 SANDPOINT      38  30  39  34  42  31 /  20  70  60  70  60  70 
 KELLOGG        39  31  40  34  42  32 /  20  70  60  70  60  70 
 MOSES LAKE     46  34  47  36  49  34 /  20  20  30  50  20  50 
 WENATCHEE      42  32  42  35  45  35 /  40  20  30  50  20  50 
 OMAK           41  31  41  34  45  32 /  40  20  40  70  30  60 
 
 &&
 
 .OTX WATCHES/WARNINGS/ADVISORIES...
 ID...NONE.
 WA...NONE.
 &&
 
 $$