Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 070302
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
902 PM MDT WED MAY 6 2015

.DISCUSSION...VERY LITTLE CONVECTIVE ACTIVITY REMAINS ACROSS
SOUTHEAST OREGON AND SOUTHWEST IDAHO THIS EVENING. MOST OF THE
CONVECTION LIES TO OUR EAST...SOUTH...AND WEST. THERE WERE
ISOLATED LIGHT SHOWERS NOTED ON RADAR IN BAKER COUNTY AND NEAR THE
NEVADA BORDER. THUNDERSTORMS HAVE NOT BEEN REPORTED IN OUR AREA
AND THE POTENTIAL IS WANING WITH SUNSET. THUS...WILL UPDATE TO
REMOVE THUNDERSTORMS FOR THE REMAINDER OF THIS EVENING. THE UPPER
LOW CENTERED OVER OREGON WILL BE THE MAIN WEATHER FEATURE TO WATCH
AS IT DIVES SOUTH THROUGH THURSDAY. WRAP-AROUND MOISTURE WILL
BRING AN INCREASE IN SHOWERS ACROSS SOUTHWEST IDAHO ON THURSDAY
WITH MOSTLY DRY CONDITIONS EXPECTED FOR SOUTHEAST
OREGON...ESPECIALLY FROM BURNS TO BAKER CITY WHICH WILL BE
FURTHEST AWAY FROM THE UPPER LOW AND IN THE DRIER AIR MASS.

&&

.AVIATION...VFR. SCATTERED TO BROKEN MID LEVEL CLOUDS. SHOWERS
AND ISOLATED THUNDERSTORMS WILL DEVELOP AFTER 18Z/THU. SURFACE
WINDS GENERALLY NW 5-15KT BECOMING NORTH TO NORTHEASTERLY 5-15KT
BY 18Z/THU...STRONGEST IN EASTERN OREGON. WINDS ALOFT AT 10K FT
MSL...NORTHERLY 5-10KT BECOMING NE 20-30KT BY 18Z/THU.

&&

.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH FRIDAY...WEATHER THROUGH FRIDAY WILL
BE TIED TO AN UPPER LOW CURRENTLY DIGGING INTO CALIFORNIA. BY
FRIDAY AFTERNOON THE MID-LEVEL CIRCULATION CENTER WILL BE ALONG
THE SOUTHERN NV/CA BORDER. SHOWER AND THUNDERSTORM ACTIVITY THIS
AFTERNOON WILL DIMINISH EXCEPT ACROSS AREAS OF WEST-CENTRAL MTNS
NORTH AND EAST OF MCCALL AND ALONG THE S-CENTRAL ID AND NV BORDER
WHICH KEEP A CHANCE OF SHOWERS THROUGH THE NIGHT. BY THURSDAY THE
LOW CENTER WILL BE OVER CENTRAL CA AND THE MAIN DRIVING MECHANISM
FOR PRECIPITATION WILL BE ENERGY CIRCULATING AROUND THE LOW.
FORECAST MODELS HAVE BEEN CONSISTENT IN BRINGING ONE SUCH FEATURE
THROUGH SW IDAHO ON THURSDAY. THERE IS DIFFERENCE ON THE INTENSITY
OF RESULTING PRECIPITATION OVER THE SNAKE RIVER VALLEY WITH
GREATER CONFIDENCE THAT MTNS IMMEDIATELY NORTH AND SOUTH OF THE
SNAKE PLAIN AND SOUTHERN MALHEUR COUNTY SEE A PERIOD OF RAIN ON
THURSDAY. A TIGHT SURFACE PRESSURE GRADIENT AND N-NE FLOW ALOFT
WILL RAMP UP WINDS OVER SE OREGON ZONES ON THURSDAY...ESPECIALLY
IN THE BAKER VALLEY. A SECOND PIECE OF ENERGY IS PROGGED TO SWING
THROUGH SOUTHERN ZONES FRIDAY AS WELL...INCREASING POPS ACROSS
SOUTHERN HARNEY/MALHEUR COUNTIES AND BOISE MTNS TO THE ID/NV
BORDER. THURSDAY IS THE COOLEST DAY WITH SOME WARMING OVER SE
OREGON ZONES FRIDAY WHILE REMAINING BELOW NORMAL ACROSS SW IDAHO.

LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...MODELS IN GOOD
AGREEMENT THROUGH THE PERIOD WITH A CONTINUATION OF THE ACTIVE
PATTERN. UPPER LOW TO OUR SOUTH WILL MOVE INTO THE FOUR CORNERS
REGION ON SATURDAY FOR NORTHEASTERLY FLOW OVER THE REGION. THIS WILL
KEEP THE THREAT FOR SHOWERS AND THUNDERSTORMS OVER SOUTHWEST IDAHO
THROUGH SATURDAY. UPPER LEVEL RIDGE BRIEFLY MOVES OVER THE REGION
SUNDAY THROUGH MONDAY WHICH WILL BRING DRIER AND WARMER CONDITIONS
TO THE REGION. THE NEXT UPPER LEVEL LOW PRESSURE SYSTEM MOVES SOUTH
ALONG THE COAST ON MONDAY REACHING NORTHERN CALIFORNIA ON TUESDAY.
BOTH 12Z GFS AND ECMWF LIFT THE OPEN TROUGH NORTHEAST ACROSS THE
PACIFIC NORTHWEST ON WEDNESDAY WHICH LOOKS TO BE THE BEST CHANCE FOR
PRECIPITATION IN THE EXTENDED PERIOD. TEMPERATURES WILL REMAIN AT OR
SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.

&&

$$

WEATHER.GOV/BOISE

DISCUSSION...BW
AVIATION.....KA
PREV SHORT TERM...DG
PREV LONG TERM....JS



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