FXUS65 KBOI 092212
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
312 PM MST WED DEC 9 2009

.SHORT TERM...TONIGHT THROUGH FRIDAY...BITTERLY COLD AIR MASS 
CONTINUES OVER THE FORECAST AREA.  ANOTHER NIGHT OF WELL BELOW ZERO 
READINGS IS IN STORE FOR MUCH OF THE AREA...WHILE THE TREASURE 
VALLEY IN SOUTHWEST IDAHO HOVERS WITHIN A COUPLE DEGREES OF 
ZERO...PLUS OR MINUS. IF BOISE DROPS BELOW ZERO TONIGHT...IT WOULD 
MARK THE THIRD CONSECUTIVE NIGHT OF BELOW ZERO READINGS. OVERNIGHT 
TEMPERATURES LOOK SIMILAR IN MANY RESPECTS TO LAST NIGHT BUT MID AND 
HIGH CLOUD TO OUR EAST MAY JUST BE ENOUGH TO HOLD MINS UP A FEW 
DEGREES ON THE EASTERN FLANK OF THE AREA. WESTERN SECTIONS OF THE 
AREA EXPECTED TO BE CLEAR. DESPITE CORE OF COLD AIR EAST OF THE 
REGION...THE CENTER OF HIGH PRESSURE REMAINS DIRECTLY OVER THE 
STATE. HAVE INCLUDED PATCHY FOG IN THE LOWER TREASURE VALLEY DURING 
THE NEXT TWO NIGHTS BUT NOT ANTICIPATING WIDESPREAD FOG CONDITIONS 
DUE TO THE VERY DRY COLD AIR MASS. AIR QUALITY IS EXPECTED TO WORSEN 
TO SOME EXTENT TOMORROW AND FRIDAY WITH SHALLOW COLD AIR REMAINING 
AND HIGH PRESSURE STAGNATING ...BUT NOT EXPECTING WIDESPREAD HAZE OR 
FOG WITH INVERSION INDICES SHOWING ONLY A MODERATE INVERSION. A WEAK 
SHORT WAVE APPROACHES THE WEST COAST FRIDAY PUSHING INCREASING 
CLOUDS INTO EASTERN OREGON WITH A SLIGHT CHANCE OF SNOW OVER THE 
STEEN MOUNTAINS AND THE OWYHEE RANGE LATE IN THE DAY. SYSTEM DOES 
NOT APPEAR TO BE STRONG ENOUGH TO SCOUR OUT COLD AIR...THUS HAVE 
KEPT COLD READINGS LOCKED IN FOR ANOTHER DAY WHICH IS LIKELY TO 
LINGER INTO THE WEEKEND.           

.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...HAVE MADE SIGNIFICANT 
CHANGES TO WEEKEND FORECAST AS ONLY SLIGHT MODIFICATION OF CURRENT 
AIRMASS IS EXPECTED. FORECAST AREA REMAINS IN CYCLONIC FLOW AROUND 
COLD ARCTIC LOW IN SW CANADA WITH MILD/MOIST PACIFIC FLOW SETUP OVER 
CENTRAL CA/NV. WHILE MODEL SOLUTIONS SHOW SIMILAR LARGE-SCALE 
PATTERN/STORM TRACK HAVE GONE CLOSER TO THE NAM/DGEX MODEL SOLUTIONS 
FOR TEMPS FOR SAT-MON WHICH SHOWS LESS MODIFICATION OF THE CURRENT 
AIRMASS. FEEL THIS IS SUPPORTED BY SOUTHERN STORM TRACK AND WEAK 
WARM-ADVECTION SIGNAL OVER THE FORECAST AREA AHEAD OF THE SYSTEM ON 
SATURDAY. GFS SOLUTION HAS TRENDED COOLER WITH TEMPS...THOUGH FEEL 
IT REMAINS TOO WARM FOR THE WEEKEND. WITH TEMPS WITHIN A COUPLE 
DEGREES OF FREEZING IN LOWER VALLEYS EXPECT PRECIP TO BE ALL SNOW 
FOR SAT/SUN. LIGHT SNOW FRIDAY NIGHT AND SATURDAY WITH WEAK 
WARM-ADVECTION WILL AMOUNT TO AN INCH OR LESS EVEN IN THE MTNS. WILL 
SEE GREATER AMOUNTS SATURDAY NIGHT AND SUNDAY AS UPPER LOW MOVES 
THOUGH NORTHERN NV AND WEAK FEATURE MOVING AROUND ARCTIC LOW SLIDES 
THROUGH THE PAC NW. ACTIVE PATTERN FOR NEXT WEEK WITH MODELS STILL 
SHOWING GRADUAL MODERATION IN AIRMASS. HAVE STAYED WITH NEAR NORMAL 
TEMPS AND ABOVE CLIMO. POPS.  

&&

.AVIATION...VFR WITH MOSTLY CLEAR SKIES THROUGH THURSDAY. COULD SEE 
LOW-VFR/MVFR VISIBILITIES DEVELOP IN THE TREASURE VALLEY WEST OF KBOI 
THURSDAY MORNING AND AGAIN FRIDAY MORNING AS THE INVERSION PERSISTS. 
WINDS LESS THAN 15 KTS FROM THE SURFACE THROUGH 10K FEET MSL.

&&

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

$$

WEATHER.GOV/BOISE

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