FXUS65 KBOI 261027
AFDBOI
AREA FORECAST DISCUSSION...CORRECTION
NATIONAL WEATHER SERVICE BOISE ID
328 AM MST THU NOV 26 2009
.SHORT TERM...TODAY THROUGH FRIDAY...THE UPPER LEVEL RIDGE AXIS WILL
DRIFT EAST OF THE ROCKIES TODAY WHILE THE SURFACE HIGH REMAINS
ANCHORED OVER SOUTHEAST IDAHO. STABILITY WILL STEADILY DECREASE AS
THE SURFACE PRESSURE GRADIENT FOR DOWN VALLEY WINDS INCREASES...
RESULTING IN AFTERNOON HIGHS SLIGHTLY ABOVE WEDNESDAY/S. HIGH CLOUDS
WILL INCREASE FROM THE WEST TODAY OVER OUR OREGON ZONES WHILE SKIES
STAY SUNNY BUT HAZY ON THE IDAHO SIDE. THE NEXT PACIFIC WEATHER
SYSTEM WILL MOVE INLAND TONIGHT SPREADING SCATTERED RAIN AND SNOW
SHOWERS INTO BAKER AND HARNEY COUNTIES AFTER MIDNIGHT. MODELS SHOW
ONLY MINOR TIMING DIFFERENCES IN THE SHORT TERM. THE UPPER LEVEL
TROUGH ASSOCIATED WITH THIS SYSTEM WILL SPLIT OVER THE INTERMOUNTAIN
REGION ON FRIDAY WITH MOST OF THE ENERGY STAYING BOTH NORTH AND
WELL SOUTH OF OUR AREA. SHOWERS WILL CONTINUE TO SPREAD EAST ON
FRIDAY WITH MOST PRECIPITATION FALLING OVER THE MOUNTAINS NORTH OF
THE SNAKE RIVER VALLEY. LIGHT TO MODERATE AMOUNTS OF SNOW WILL
ACCUMULATE ABOVE 5000 FEET...BUT TOTALS ARE NOT EXPECTED TO BE
ENOUGH TO CAUSE SIGNIFICANT IMPACTS.
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...BREEZY EAST OF BOISE
FRIDAY EVENING AS AN UPPER TROUGH EXITS THE REGION. GFS IS FASTER
EXITING THIS TROUGH WHILE THE FAVORED SLOWER EC KEEPS COLD NORTHERLY
FLOW OVER THE REGION. THIS ALLOWS FOR BELOW NORMAL TEMPERATURES AND
MAINLY DRY WX THIS WEEKEND. SO HAVE NUDGED ALL BUT THE FAR NE TO DRY
WX AS THE STORM TRACK SHIFTS EAST. NO CHANGES MID/LATE PERIODS AS
LARGE DIFFERENCES IN THE MODELS CONTINUE. CURRENT FORECAST IS
SUPPORTED BY THE WIDELY FAVORED SLOWER EC SOLUTION. NOW THE EC IS
ALSO DEEPER THAN ITS PREV. RUN AND MUCH DEEPER THAN THE GFS...WITH A
TROUGH OVER IDAHO AND THE NW TUESDAY. WILL HOLD OFF CHANGES IN DAY
5...OR LATER. LOOKING AT THE LONGEST RANGES THE NCEP FORECASTS FOR
THE FIRST WEEK OF DECEMBER SHOW DRIER THAN NORMAL CONDITIONS...WHICH
ARE NEARLY CENTERED OVER SE OREGON/SW IDAHO.
&&
.AVIATION...AREAS OF DENSE FREEZING FOG IN THE LONG VALLEY UNTIL
16Z...BECOMING VFR TOWARDS 20Z. PATCHY HAZE BRIEFLY 5SM UNTIL 14Z.
APPROACHING PACIFIC SHORT WAVE SPREADING SCT-BKN HIGH CLOUDS FROM NE
OREGON THIS MORNING THROUGH CENTRAL IDAHO THIS AFTERNOON. CIGS
DROPPING TO OBSCURE MOUNTAIN TOPS IN THE BLUES AND CENTRAL IDAHO
09-12Z FRIDAY WITH SEVERAL HOURS OF LIGHT IFR SNOW IN THE MOUNTAINS.
AND EXITING OREGON/IDAHO 00Z/09Z RESPECTIVELY. SFC WINDS LIGHT.
LIGHT WINDS ALOFT UNTIL 18Z THEN AVERAGING 240/25KTS THROUGH FRIDAY.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
SHORT TERM...JT
LONG TERM....VM
AVIATION.....VM