000
FXUS65 KBOI 240409
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
909 PM MST MON NOV 23 2009

.DISCUSSION...MINIMUM TEMPERATURES WILL HAVE TO BE LOWERED A FEW
DEGREES IN SOME OF THE HIGHER ELEVATIONS WHERE TEMPS HAVE ALREADY
GONE BELOW FORECAST MINS. OTHERWISE...FORECAST IS ON TRACK. WE ARE
STILL EXPECTING MORE CLOUDS IN THE NORTH THAN IN THE SOUTH...PATCHY
FOG MAINLY IN PORTIONS OF SOUTHEAST OREGON AND THE LOWER TREASURE
VALLEY...AND ISOLATED SNOW SHOWERS MAINLY IN BAKER COUNTY. UPDATE
WILL BE OUT AROUND 930 PM MST.

&&

.AVIATION...VFR TONIGHT.  INCREASING MID-LEVEL CEILINGS OVER THE
WEST CENTRAL AND BAKER COUNTY MTNS WITH HIGH LEVEL CEILINGS
EVERYWHERE ELSE.  LOCAL IFR IN VALLEY FOG WILL DEVELOP AFTER 06Z
WITH POSSIBLE IFR STRATUS OVER THE WESTERN MAGIC VALLEY.  FOG AND
STRATUS WILL DISSIPATE BY TUESDAY AFTERNOON.  EXPECT AREAL COVERAGE
OF THE STRATUS AND FOG TO INCREASE TUESDAY NIGHT AND WEDNESDAY.
SURFACE WINDS TONIGHT WILL BE LIGHT WITH MODERATE NORTHWEST WINDS
ALOFT.

WITH AN UPPER LEVEL RIDGE DEVELOPING OVER THE REGION FOR THE NEXT
FEW DAYS KBOI WILL LIKELY DEVELOP MVFR-IFR CONDITIONS IN FOG AND
STRATUS BY EARLY WEDNESDAY MORNING.  IF FOG DEVELOPS BEFORE THE LOW
STRATUS KBOI COULD BE CLOSE TO MINIMUMS WEDNESDAY MORNING.  DOES
LOOK HOPEFUL THAT CONDITIONS WILL CLEAR WEDNESDAY AFTERNOON BEFORE
REDEVELOPING WEDNESDAY NIGHT.

&&

.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH WEDNESDAY...OTHER THAN A PASSING
MAINLY DRY COLD FRONT TUESDAY LOOK FOR A WEAK INVERSION TONIGHT
AND STRONGER AND MORE MOIST INVERSION TUESDAY NIGHT INTO THE LONG
TERM. AFTERNOON EROSION OF THE INVERSION AND ACCOMPANYING
STRATUS/FOG IS EXPECTED WITH THE POSSIBLE EXCEPTION OF THE AREA
FROM VALE TO WEST OF MIDDLETON IDAHO WEDNESDAY. TEMPERATURES
GENERALLY ON TRACK OR SLIGHT WARMER THAN GUIDANCE WITH SOME
CHANGES MADE FOR INVERSION WEST OF BOISE AND AT JEROME. LIGHT WINDS
OF LESS THAN 5 KTS AVERAGE AND LOW MIXING LEVEL OF 2000 FT AGL OR
LESS LOOK TO REMAIN OVER THE LOWER TREASURE VALLEY UNTIL TUESDAY
AFTERNOON.

LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...INVERSION HOLDS ON
INTO THURSDAY. EXPECT FOG/STRATUS TO RETURN TO THE LOWER TREASURE
VALLEY AND IN VICINITY OF THE SNAKE RIVER EARLY THURSDAY MORNING.
SURFACE WINDS AND WINDS ALOFT INCREASE THROUGH THE DAY WHICH WILL
HELP MIX OUT ALL BUT THE LOWEST ELEVATIONS ALONG THE SNAKE RIVER. A
STORM SYSTEM IS STILL TIMED FOR FRIDAY INCREASING THE CHANCE OF
VALLEY RAIN AND MTN SNOW. A SECOND SYSTEM DROPS INTO THE
INTERMOUNTAIN WEST EARLY SATURDAY CONTINUING THE CHANCE OF PRECIP.
AMOUNTS WITH THESE SYSTEMS WILL BE FAIRLY LIGHT AS BAND OF HIGHER PW
VALUES REMAIN SOUTH AND WEST OF THE REGION. UPPER RIDGE WITH WARM
AIR ALOFT REDEVELOPS OVER THE AREA FOR SUN/MON BRINGING RETURN TO AN
INVERSION PATTERN.

&&

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

$$

WEATHER.GOV/BOISE

DISCUSSION...SP
AVIATION.....JA
PREV SHORT TERM...VM
PREV LONG TERM....DG/DD