Wind Advisory 10, NWS Boise, ID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
311 PM MDT TUE APR 27 2010

.SHORT TERM...TONIGHT THROUGH THURSDAY...THUNDERSTORMS HAVE FORMED
AS OF 245 MDT IN A ZONE FROM THE LEE OF THE STEENS/DIAMOND-
FRENCHGLEN THROUGH THE LOWEST ELEVATIONS OF THE TREASURE
VALLEY/NYSSA-ONTARIO. STORMS WILL RACE TO THE NE AROUND 30 MPH AS
THE ZONE SHIFTS TO THE EAST THROUGH THIS AFTERNOON. WILL STILL BE
WATCHING FOR BOW ECHOES AND GUSTY WINDS TO AROUND 50 MPH. THIS
AREA WAS JUST AHEAD OF A COLD FRONT MOVING THROUGH CENTRAL OREGON
AND WHERE LOTS OF SUNBREAKS WERE NOTED ON THE SATELLITE IMAGERY
THROUGH THE EARLY AFTENROON. A DEEP COLD TROUGH PUSHING INLAND IS
AIDING LIFT WITH THE FRONT. A BAND OF STEADIER RAIN ORIENTED NW TO
SE FROM BAKER TO FAIRFIELD TODAY WILL CONTINUE TO LIFT THROUGH
VALLEY COUNTY TO BANNER SUMMIT THIS AFTERNOON. THE FRONT WILL
CONTINUE TO PUSH THROUGH SW IDAHO THIS EVENING WITH ISOLATED
THUNDERSTORMS AND POCKETS OF HEAVY RAIN. GUSTS T0 50 MPH WITH
STRONGER THUNDERSTORMS AS WELL AS GUSTS AROUND 45 MPH WITH THE
FRONT...AND FOR 2-4 HOURS AFTER ITS PASSAGE. THE ASSOCIATED UPPER
LEVEL TROUGH WILL CONTINUE TO PUSH INLAND FOR BRISK CONDITIONS
THROUGH THURSDAY. HIGHEST PW AND MOISTURE WILL BE WITH THE FRONT
THOUGH. POPS HIGHEST 18-06Z IN THE AFTERNOONS AND EVENING WILL
INCLUDE A THREAT OF SMALL HAIL AS WELL.

.LONG TERM...THURSDAY NIGHT THROUGH SUNDAY...UNSEASONABLY COOL
TEMPERATURES AND CHANCES OF PRECIPITATION /MAINLY ACROSS SW ID/ TO
CONTINUE THROUGH THE REMAINDER OF THE WEEK. UPPER LEVEL TROUGH
/OVER THE FORECAST AREA TODAY/ WILL DIG EASTWARD AND CLOSE OFF
OVER MONTANA AND THE DAKOTAS BY LATE THURSDAY. UPPER LOW WILL
PROGRESSIVELY BROADEN OVER THE CENTRAL U.S. THURSDAY NIGHT THROUGH
SATURDAY... LEAVING SE OREGON AND SW IDAHO UNDER BROAD CYCLONIC
FLOW ALOFT. HAVE MAINTAINED HIGHER POPS ACROSS SE OREGON THURSDAY
NIGHT AS UPPER LOW LINGERS OVER THE INTERMOUNTAIN REGION. EXPECT
FRI/SAT POPS TO BE FOCUSED NEAR LINGERING MOISTURE OVER SW IDAHO
AND DRIER CONDITIONS ACROSS SE OREGON. BY SUNDAY...CENTRAL U.S.
TROUGH WILL DIG FARTHER EAST ALLOWING UPPER LEVEL RIDGE OFF THE
PAC NW COAST TO MOVE INLAND. EXPECT WARMER TEMPERATURES
SUNDAY...BUT FORECAST HIGHS STILL 5-7 F BELOW EARLY MAY NORMALS.
MONDAY AND TUESDAY...MODELS CONTINUE TO STRUGGLE WITH THE
EXTENDED. THOUGH EACH DEPICT A RIDGE OFFSHORE...THE LATEST GFS
STILL PREFERS TO COMPRESS THE HIGH AND PUSH IT TOWARD THE PACNW
WHICH PLACES THE AREA IN A DRY AND WARM FLOW. MEANWHILE THE ECMWF
HOLDS A STRONGER VERSION OF THE RIDGE WELL OUT IN THE PACIFIC AND
ALLOWS A COLD LOW TO SPILL OVER IT...WHICH WOULD KEEP THE NW COOL
AND WET. NATIONAL GUIDANCE FAVORS THE EC ENSEMBLES WHICH HAVE
CONSISTENTLY DEPICTED A HIGH AMPLITUDE LONGWAVE RIDGE IN THE
SOUTHEASTERN PORTION OF THE CONUS...A SCENARIO THAT TENDS TO
MAINTAIN A TROUGH OVER THE WEST. FINAL DECISION WAS TO FOLLOW THE
CONSISTENT ECMWF ALBEIT CONSERVATIVELY...WITH NEAR CLIMATOLOGY
POPS AND SLIGHTLY BELOW CLIMO TEMPERATURES.

MONDAY AND TUESDAY...MODELS CONTINUE TO STRUGGLE WITH THE
EXTENDED. THOUGH EACH DEPICT A RIDGE OFFSHORE...THE LATEST GFS
STILL PREFERS TO COMPRESS THE HIGH AND PUSH IT TOWARD THE PACNW
WHICH PLACES THE AREA IN A DRY AND WARM FLOW. MEANWHILE THE ECMWF
HOLDS A STRONGER VERSION OF THE RIDGE WELL OUT IN THE PACIFIC AND
ALLOWS A COLD LOW TO SPILL OVER IT...WHICH WOULD KEEP THE NW COOL
AND WET. NATIONAL GUIDANCE FAVORS THE EC ENSEMBLES WHICH HAVE
CONSISTENTLY DEPICTED A HIGH AMPLITUDE LONGWAVE RIDGE IN THE
SOUTHEASTERN PORTION OF THE CONUS...A SCENARIO THAT TENDS TO
MAINTAIN A TROUGH OVER THE WEST. FINAL DECISION WAS TO FOLLOW THE
CONSISTENT ECMWF ALBEIT CONSERVATIVELY...WITH NEAR CLIMATOLOGY
POPS AND SLIGHTLY BELOW CLIMO TEMPERATURES.

&&

.AVIATION...AREAS OF MVFR /AND LOCAL IFR/ IN RAIN SHOWERS AND
ISOLATED THUNDERSTORMS THROUGH 06Z. SUSTAINED S-W SURFACE WINDS WILL
AVERAGE 15-25 KTS...WITH LOCAL GUSTS TO 45 KTS THROUGH 04Z. EXPECT
MODERATE RAIN...IFR CIGS AND ERRATIC WIND SHIFTS IN THE VICINITY OF
STORMS. STRONG SOUTHWESTERLY FLOW ALOFT. AFTER 06Z...WINDY
CONDITIONS AND MVFR SHOWERS WILL PERSIST. SNOW LEVELS DROPPING TO
AROUND 4500 FT OVERNIGHT...FOR IFR SNOW SHOWERS AT KMYL BY EARLY
MORNING.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WIND ADVISORY UNTIL 9 PM MDT THIS EVENING IDZ015-029-030.
     WIND ADVISORY UNTIL 9 PM MDT THIS EVENING IDZ016.
OR...WIND ADVISORY UNTIL 8 PM MDT /7 PM PDT/ THIS EVENING ORZ061-063.
&&

WEATHER.GOV/BOISE

SHORT TERM...VM
LONG TERM....MT/BB
AVIATION.....MT