938 
FXUS65 KBOI 212205
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
305 PM MST SAT NOV 21 2009

.SHORT TERM...TONIGHT THROUGH MONDAY...WINDS WILL BUILD TONIGHT
FROM THE SOUTHEAST AND SOUTH THEN SHIFT TO SW AND NW SUNDAY BEHIND
A FAST MOVING COLD FRONT. HUGE..IE...-4/-6 TO +10/+15 MB PRESSURE
FALL/RISE COUPLET STAYS TO OUR NW AND N FOR LOCALLY VERY WINDY
CONDITIONS ACROSS SE OREGON AND BREEZY AREAS FOR SW IDAHO...BUT NO
HEADLINES FOR WIND. SNOW AND AREAS OF BLOWING/DRIFTING SNOW ARE
EXPECTED WITH THIS FAST MOVING SYSTEM SUNDAY SO AN ADVISORY FOR
SNOW AND BLOWING SNOW HAS BEEN HOISTED ACROSS BAKER COUNTY...THE
WEST CENTRAL AND BOISE MOUNTAINS. GUSTY NW WINDS DIMINISH RAPIDLY
MONDAY NIGHT AS HIGH PRESSURE BUILDS IN...WITH LIGHT WINDS AND
MOSTLY CLEAR SKIES. COUPLED WITH NEW SNOW COVER...GENERALLY ABOVE
3500 FEET...LOW TEMPS WILL PLUMMET TO SINGLE DIGITS COLDEST SPOTS
SUCH AS FAIRFIELD AND MID 20S...TEENS ACROSS THE RELATIVELY MILDER
LOCALES. LIGHT WINDS AND A COLD START MONDAY LOOK TO KEEP TEMPS
BELOW NORMAL AND NEAR TO BELOW MOS.


.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...UPPER RIDGE BUILDS INTO 
THE PACIFIC NW ON TUESDAY. WEAK SYSTEM MOVING THROUGH THE PANHANDLE 
TUESDAY AFTERNOON WILL DO LITTLE MORE THAT INCREASE CLOUDS OVER THE 
WEST CENTRAL MTNS. WITH WARMING ALOFT...INVERSION SETS UP IN THE 
LOWER ELEVATIONS FOR TUE/WED. INTRODUCED FOG INTO THE FORECAST FOR
TUESDAY NIGHT AND WEDNESDAY IN THE LOWER TREASURE...WEISER AND BAKER 
VALLEYS. LESS CONFIDENT ON DEVELOPMENT OF FOG/STRATUS OVER BOISE  
WEDNESDAY MORNING SO HAVE LEFT IT OUT FOR NOW. GOOD MODEL AGREEMENT 
THAT INVERSION IS SHORT-LIVED...AS ANOTHER STORM ENTERS THE PAC NW 
LATE IN THE WEEK. THE 12Z SOLUTIONS ARE IN BETTER AGREEMENT ON 
BRINGING THE STORM THROUGH THE INTERMOUNTAIN NW ON FRIDAY. WINDS 
AHEAD OF THE SYSTEM WOULD LIKELY CLEAR OUT ANY FOG/STRATUS IN THE 
LOWER VALLEYS THANKSGIVING DAY. LOOKS LIKE RAIN IN THE VALLEYS ON 
FRIDAY WITH MTN SNOW. PATTERN REMAINS ACTIVE THROUGH NEXT WEEKEND.

&&

.AVIATION...WIDESPREAD IFR CONDITIONS IN SNOW DEVELOPING SUNDAY 
MORNING...OVER SE OREGON AFTER 06Z AND SW ID AFTER 09Z. WILL SEE 4-6 
HOURS OF IFR CONDITIONS AT BOISE SUNDAY MORNING. IFR CONDITIONS 
CONTINUE IN SW IDAHO MTNS AND WESTERN MAGIC VALLEY THROUGH SUNDAY 
AFTERNOON. CONDITIONS IMPROVE TO VFR IN SE OREGON AND TREASURE 
VALLEY OF SW IDAHO SUNDAY AFTERNOON. GUSTY SE SURFACE WINDS EARLY 
SUNDAY MORNING SHIFTING TO THE WEST IN THE AFTERNOON. STRONG 
WESTERLY WINDS ALOFT OF 40-60 KTS ON SUNDAY. 

OUTLOOK...DEVELOPMENT OF INVERSION NEXT WEEK WILL BRING CHANCE OF 
IFR CONDITIONS IN FOG/STRATUS TO TREASURE/BAKER/WEISER VALLEYS ON 
WEDNESDAY. 


&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WINTER WEATHER ADVISORY FROM 4 AM TO 2 PM MST SUNDAY FOR IDZ011-
     IDZ013.
OR...WINTER WEATHER ADVISORY FROM 1 AM TO 10 AM PST SUNDAY FOR ORZ062.
&&

$$

WEATHER.GOV/BOISE

SHORT TERM...VM
LONG TERM....DG/DD
AVIATION.....DG