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000
FXUS65 KBOI 121705
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1005 AM MST THU DEC 12 2013

.DISCUSSION...MOSTLY SUNNY SKIES OVER THE AREA THIS MORNING...WITH
THE EXCEPTION OF A SMALL AREA OF LOW CLOUDS OVER CENTRAL MALHEUR
COUNTY...EXTREME NE HARNEY COUNTY...AND ISOLATED MOUNTAIN VALLEYS
SUCH AS IN FAR SW BAKER COUNTY AND NEAR MCCALL. THESE CLOUDS ARE
EXPECTED TO BURN OFF TODAY...AS OPPOSED TO YDAY WHEN THEY LINGERED
ALL DAY IN SOME AREAS. TEMPS WILL REMAIN LOW IN THE VALLEYS WHERE
THE INVERSION IS HANGING TOUGH...WITH SOME SLIGHT WARMING AT
ELEVATIONS ABOVE AROUND 6000 FEET. THE LATEST THINKING ON THE
SYSTEM HEADED IN TOMORROW IS THAT IT WILL BE QUITE DRY...WITH ONLY
TRACE AMOUNTS OF SNOW IN THE LOWER VALLEYS AND JUST AN INCH OR SO
EVEN AT HIGHER ELEVATIONS. NO UPDATE IS PLANNED FOR THIS MORNING.

&&

.AVIATION...MVFR IN FOG/STRATUS ACROSS PORTIONS OF SOUTHEAST OREGON
/MAINLY EAST OF KBNO/ AND NEAR KMYL. CIGS AND VISIBILITIES FORECAST
TO IMPROVE TO VFR BETWEEN 18Z AND 02Z. LIGHT SURFACE WINDS -
GENERALLY 12 KNOTS OR LESS. WESTERLY WINDS ALOFT WILL AVERAGE 20 KTS
AT 10K FEET MSL.

&&

.PREV DISCUSSION...
SHORT TERM...TONIGHT HAS BEEN COLDER THAN LAST NIGHT IN MOST OF
THE SNAKE BASIN DUE TO FEWER CLOUDS AND BETTER RADIATION OFF THE
SNOW SURFACE. PATCHY FOG WILL CONTINUE IN THE VALLEYS THROUGH MID-
MORNING.  SURFACE-BASED INVERSION REMAINS STRONG AND WILL AGAIN
LIMIT MAX TEMPS IN THE VALLEYS...BUT MOUNTAINS WILL BE A LITTLE
WARMER THAN YESTERDAY.  MOS...ESPECIALLY MAV...CONTINUES TO WARM
THE VALLEYS TOO FAST.  SHORT WAVE TROUGH IN THE EASTERN PACIFIC NEAR
130W THIS MORNING WILL COME INLAND AND WEAKEN AS IT PASSES THROUGH
OUR CWA.  AN INCH NEW SNOW EXPECTED TONIGHT AND FRIDAY MORNING IN
OREGON MOUNTAINS AND NORTHERN MOUNTAINS IN IDAHO...NO MORE THAN
FLURRIES ELSEWHERE.  TROUGH WILL EXIT INTO NEVADA AND UTAH FRIDAY
WITH COOLER NORTHWESTERLY FLOW OVER HIGHER TERRAIN.  SYSTEM LOOKS
TOO WEAK TO BREAK THE INVERSION IN THE VALLEYS.  HOWEVER...THURSDAY
NIGHT WILL BE MILDER THAN CURRENT NIGHT DUE TO MORE CLOUDS.  FRIDAY
MAX TEMPS IN THE VALLEYS WILL BE SLIGHTLY MILDER THAN TODAY. LIGHT
WINDS TODAY EXCEPT NEAR JEROME/ID WHERE NORTHEAST WINDS 15 TO 25 MPH
WILL CONTINUE TODAY.  LIGHT WINDS IN ALL AREAS TONIGHT...AND LIGHT
WEST/NORTHWEST WINDS IN ALL AREAS FRIDAY.

LONG TERM...FRIDAY NIGHT THROUGH THURSDAY...WEAK DISTURBANCE EXITS
THE AREA FRIDAY NIGHT AND ANOTHER RIDGE BUILDS OFF THE NORTHERN
CALIFORNIA COAST. EXPECT THE REGION TO BE UNDER DRY NORTHWESTERLY
FLOW ALOFT THEREAFTER THROUGH WEDNESDAY. ONCE AGAIN HAVE KEPT
EXTENDED TEMPERATURES IN THE VALLEYS COLD AS THE SNOW REMAINS ON THE
GROUND AND ARCTIC AIR REMAINS. DO NOT BELIEVE THE SYSTEM ON FRIDAY
WILL BE STRONG ENOUGH TO SCOUR OUT THE COLD AIR AND THE SNOW COVER
IS EXTENSIVE ACROSS THE GREAT BASIN. MODEL GUIDANCE IS TOO WARM AND
DOES NOT HAVE A GOOD HANDLE ON THE COLD AIR ENTRAPPED ACROSS THE
ENTIRE GREAT BASIN. GUIDANCE WANTS TO MELT THE SNOW AND ERODE THE
COLD AIR TOO QUICKLY. THE UPPER LEVEL RIDGE SHIFTS OFFSHORE INTO THE
NORTHEAST PACIFIC BY WEDNESDAY EXTENDING NORTH INTO THE GULF OF
ALASKA...MUCH LIKE THE PATTERN WE SAW TWO WEEKS AGO. THIS OPENS THE
DOOR FOR ANOTHER COLD UPPER LEVEL TROUGH TO SLIDE DOWN THE BRITISH
COLUMBIA COAST BY THURSDAY FOR A ROUND OF PRECIPITATION PAST
THURSDAY INTO NEXT WEEKEND. THIS SYSTEM SHOULD BE STRONG ENOUGH TO
MIX OUT THE INVERSION STARTING WEDNESDAY AND THE FORECAST REFLECTS
THAT.

&&

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

&&

$$

WEATHER.GOV/BOISE

DISCUSSION...SP
AVIATION.....MT
PREV SHORT TERM...LC
PREV LONG TERM....KA