FXUS65 KBOI 221619 CCA
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
917 AM MST TUE DEC 22 2009

.DISCUSSION...WORST CONDITIONS THIS MORNING ARE EAST OF BOI WHERE
SNOW AND GUSTY WEST WINDS CONTINUE AND ICE HAS FORMED ON ROADS
INCLUDING I-84.  KCBX RADAR SHOWED SNOW DECREASING FROM WEST TO
EAST WITH WRN EDGE ALONG OREGON/IDAHO BORDER AT 16Z.  LATEST NAM 
SHOWS THE MAIN UPPER LOW HEADING RAPIDLY SSEWD FROM CENTRAL OREGON 
THIS MORNING TO ARIZONA WED MORNING...BUT AS IT GETS INTO NEVADA 
THIS AFTERNOON IT IS PROGGED TO ROTATE A LOBE BACK OVER SCENTRAL 
IDAHO AND PROLONG SNOW THERE.  LATEST NAM SHOWS SNOW CONTINUING
INTO TONIGHT IN TWIN FALLS COUNTY...AND LATEST MET GUIDANCE
PREDICTS TWO MORE INCHES OF SNOW FOR TWF TONIGHT.  WE WILL
THEREFORE HAVE TO EXTEND THE WINTER WX ADVISORY BEYOND CURRENT
1 PM EXPIRATION...NEW EXPIRATION WILL BE 9 PM TONIGHT.  COLDER
AND DRIER AIR WILL COME INTO OUR OTHER ZONES FROM THE NORTH
TONIGHT AND WEDNESDAY AND EARLY FORECAST ALREADY SHOWS THIS TREND.

&&

.AVIATION...VFR CONDITIONS ACROSS SOUTHEAST OREGON WILL CONTINUE 
TODAY WITH ONLY WIDELY SCATTERED MVFR SNOW SHOWERS. ON THE IDAHO 
SIDE AREAS OF MVFR/IFR SNOW WILL CONTINUE THIS MORNING...ENDING IN 
THE TREASURE VALLEY BY 18Z BUT CONTINUING EAST OF KMUO AND OVER THE 
MOUNTAINS THROUGH THIS EVENING. SURFACE WINDS WILL BE NORTHWEST 
15-25 KTS DECREASING TO 10-15 KTS AFTER 03Z. WINDS ALOFT WILL BE 
LIGHT TO MODERATE NORTHEAST TO SOUTHEAST BECOMING MODERATE NORTH 
AFTER 06Z. 

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WINTER WEATHER ADVISORY UNTIL 9 PM MST TUESDAY FOR              
        IDZ016-IDZ030.
OR...NONE.  

&&

$$

WEATHER.GOV/BOISE

DISCUSSION...LC
AVIATION.....JT
PREV SHORT TERM...GS
PREV LONG TERM....MT/JS