AREA FORECAST DISCUSSION

 
 FXUS65 KBOI 230949
 AFDBOI
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE BOISE ID
 250 AM MST MON NOV 23 2009
 
 .SHORT TERM...TODAY THROUGH TUESDAY...HIGH PRESSURE BUILDING OVER 
 THE FORECAST AREA FOR BENIGN WEATHER THE NEXT TWO DAYS. HOWEVER...A 
 WEAK DISTURBANCE IS FORECAST TO SLIDE SOUTHWARD LATE TONIGHT FROM 
 THE PACIFIC NORTHWEST...EVENTUALLY WASHING OUT OVER CENTRAL IDAHO 
 WITHIN THE BUILDING UPPER RIDGE.  MODELS HANDLING THIS FEATURE 
 SLIGHTLY DIFFERENTLY WITH THE NAM MORE AGGRESSIVE SHOWING A MORE 
 SOUTHERLY POSITION AND LIMITED POPS...WHILE THE GFS KEEPS THE 
 FEATURE NORTH OF OUR FORECAST AREA IN CENTRAL IDAHO ACROSS THE 
 SALMON RIVER AND POINTS NORTH. HAVE CHOSEN A COMPROMISE BETWEEN THE 
 TWO AND ALLOWED A SMATTERING OF SLIGHT CHANCE POPS ACROSS BAKER 
 COUNTY OREGON AND VALLEY COUNTY IDAHO LATE TONIGHT AND TUESDAY. 
 OTHERWISE...WITH THE ABOVE MENTIONED RIDGE TAKING HOLD...WEATHER 
 REMAINS QUIET WITH A GOOD AMOUNT OF SUNSHINE TODAY AND PARTLY TO 
 MOSTLY CLOUDY SKIES TUESDAY. TEMPERATURES COOL TODAY WITH SURFACE 
 BASED INVERSION STRENGTHENING...BUT WARMING BECOMING MORE 
 SIGNIFICANT TUESDAY AS HIGH CENTER DRIFTS OVER EASTERN IDAHO 
 BRINGING EASTERLY COMPONENT FLOW BACK TO OUR REGION AIDING LOW LEVEL 
 WARMING.      
 
 .LONG TERM...TUESDAY NIGHT THROUGH MONDAY...THE PATTERN THROUGH THE 
 PERIOD IS PROGRESSIVE. MODEL AGREEMENT AND RUN TO RUN CONSISTENCY 
 ARE QUITE GOOD THROUGH FRIDAY. A RIDGE OVER OUR AREA WEDNESDAY MOVES 
 EAST OF THE ROCKIES THURSDAY FOLLOWED BY A SHORTWAVE TROUGH CROSSING 
 THE REGION THURSDAY NIGHT THROUGH FRIDAY NIGHT. OVER THE WEEKEND THE 
 CANADIAN DIVERGES FROM THE GFS40/GFS ENSEMBLE MEAN/ECMWF BY BRINGING 
 US A MUCH COLDER PATTERN WITH A RIDGE BUILDING OFFSHORE RATHER THAN 
 OVER THE WEST COAST STATES. WE ARE STAYING WITH THE MILDER 
 GUIDANCE...WITH TEMPERATURES 5 TO 10 DEGREES ABOVE NORMAL ON 
 THANKSGIVING DAY...COOLING TO NEAR NORMAL FOR SATURDAY THROUGH 
 MONDAY. BEST CHANCES OF PRECIPITATION WILL BE WITH THE TROUGH 
 PASSAGE THURSDAY NIGHT THROUGH FRIDAY NIGHT. FOR THE REST OF THE 
 PERIOD POPS WILL BE BELOW NORMAL FOR OUR SOUTHERN ZONES AND NEAR 
 NORMAL FOR BAKER COUNTY AND THE WEST CENTRAL IDAHO MOUNTAINS. 
 
 &&
 
 .AVIATION...LOCAL MVFR CEILINGS AND AREAS OF TERRAIN OBSCURATION 
 WILL PERSIST IN THE WEST CENTRAL IDAHO MOUNTAINS THROUGH THIS 
 MORNING. OTHERWISE EXPECT VFR CONDITIONS TODAY THROUGH TUESDAY. 
 WITH AN INVERSION INTENSIFYING TONIGHT THROUGH WEDNESDAY...PATCHY 
 NIGHT AND MORNING FOG WILL BE POSSIBLE IN MOUNTAIN VALLEYS...
 ESPECIALLY LATE TUESDAY NIGHT AND WEDNESDAY MORNING. SURFACE WINDS 
 WILL BE LIGHT TODAY. WINDS ALOFT WILL BE LIGHT TO MODERATE 
 NORTHWEST. 
 
 &&
 
 .BOI WATCHES/WARNINGS/ADVISORIES...
 ID...NONE.
 OR...NONE.
 &&
 
 $$
 
 WEATHER.GOV/BOISE
 
 SHORT TERM...GS
 LONG TERM....JT/MT
 AVIATION.....JT