FXUS65 KBOI 072206
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
306 PM MST MON DEC 7 2009

.SHORT TERM...TONIGHT THROUGH WEDNESDAY...SATELLITE...RADAR AND
SURFACE OBS SHOW PATCHES OF VERY LIGHT SNOW FROM SOUTH OF EMMETT
THROUGH SOUTHERN TWIN FALLS COUNTY. MID/UPPER CLOUD SHIELD ACROSS
SW IDAHO TO SHIFT EAST AS THE UPPER TROUGH EXITS SW IDAHO 6-9Z.
THIS LOOKS TO ALLOW 1 OR 2 INCHES OF SNOW...TO LOCALLY 5 INCHES
SOUTHERN SAWTOOTH MOUNTAINS...OF VERY FLUFFY SNOW TO ACCUMULATE
ACROSS SOUTHERN TWIN FALLS COUNTY. WEBCAMS I.E. ROGERSON... STILL
SHOW ROADWAYS SO NO HEADLINES AS SNOW ACCUMULATION IS VERY LIGHT.
8MBS SURFACE PRESSURE GRADIENT OVERNIGHT FROM JEROME TO BAKER IS
EXPECTED TO INHIBIT FOG FORMATION EVEN OVER FRESH SNOW. VERY COLD
THE NEXT TWO NIGHT WITH WIND CHILL VALUES TO AROUND 10 BELOW IN
THE POPULATED SOUTHERN VALLEYS. /NO HEADLINES UNTIL 20 BELOW WIND
CHILL VALUES/. SHAVED TEMPS A BIT EACH PERIOD AS COLD AIRMASS AND
SNOW COVER COMBINE WITH LOW SUN ANGLE/INSOLATION IN THE SHORT
TERM. LIGHTER WINDS TUESDAY NIGHT/EARLY WEDNESDAY COULD ALLOW FOG
FORMATION BUT ICE/SNOW MAY INHIBIT THAT...BY PULLING THE LOW LEVEL
MOISTURE INTO THE ICE/SNOW. SO WILL HOLD OFF ADDING PATCHY FOG
TOMORROW NIGHT FOR NOW. COLD NW FLOW ALOFT AND DOME OF HIGH
PRESSURE OVER THE REGION WEDNESDAY FOR LIGHTER WINDS...AND ONLY
SLIGHTLY WARMER HIGHS WEDNESDAY AFTERNOON.

.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...MODELS REMAIN IN GOOD 
AGREEMENT BY INDICATING THAT THE FLOW OVER THE REGION BACKS MORE TO 
THE NORTHWEST AS BULK OF THE COLD AIR AND DYNAMICS SLIDE EASTWARD 
THURSDAY. HAVE ESSENTIALLY REMOVED POPS FOR THE THUR-SATURDAY TIME 
PERIOD AS ANY DISTURBANCES IN THE FLOW SHOULD REMAIN FAR ENOUGH 
EAST. HAVE ALSO BACKED OFF HOW QUICKLY TEMPS WILL WARM ESP HERE IN 
THE TREASURE VALLEY NOW THAT THERE IS 1-4 INCHES OF SNOW ON THE 
GROUND. 

WHATS DIFFERENT IN THE MODELS TODAY IN BOTH THE EC AND GFS IS THE 
HANDLING OF THE SUBTROPICAL WESTERLIES AND HOW FAR NORTH DO THEY LIFT 
INTO THE AREA AND WHEN. THESE MODELS TAKE A SYSTEM THAT WAS PROGGED 
TO MOVE INTO NORTHERN CALIF THEN DROP TO THE SOUTHEAST REMAINING OUT 
OF THE AREA ON THUR AND FRIDAY. NOW THE MODELS BRING THAT SYSTEM A 
BIT FURTHER NORTH AND NOW ON FRI/SAT. THIS BRINGS A SLIGHT CHANCE OF 
PRECIPITATION TO THE NEVADA BORDER AREA FRIDAY. HAVE INCREASED POPS 
TO AROUND CLIMO FOR THE SATURDAY TIME PERIOD AS THE MOIST FLOW MOVES 
INTO OREGON. THIS SHOULD ALSO HELP RAISE THE SNOW LEVELS OFF THE 
VALLEY FLOORS OVER THE WEEKEND. FOR THE REST OF THE WEEKEND 
CONDITIONS WILL TEND TO BE WILD AND MILD WITH ABOVE CLIMO POPS. 
TENDED TO GO WITH A GFS/EC MODEL BLEND FOR THE SUNDAY-TUESDAY TIME 
PERIOD. 

&&

.AVIATION...VFR CONDITIONS ACROSS THE WEST CENTRAL MOUNTAINS AND 
EASTERN OREGON THROUGH TUESDAY. ACROSS THE REMAINDER OF THE REGION 
MVFR CONDITIONS ARE EXPECTED THROUGH THE EVENING AT KBOI IMPROVING 
BEFORE MIDNIGHT AS LOW CLOUDS EXIT. AREAS TO THE EAST OF BOISE 
SHOULD REMAIN MVFR WITH LOCAL POCKETS OF LIFR IN -SN/BR AND LOW 
CLOUDS AS THAT AREA THROUGH 12Z...THEN SLOW IMPROVEMENT. LIGHT TO 
MODERATE EAST/NE WINDS EXPECTED THROUGH TUESDAY THEN SHIFT 
NORTHWEST.

&&

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

$$

WEATHER.GOV/BOISE

SHORT TERM...VM
LONG TERM....CR/BB
AVIATION.....CR