770 
fxus65 kboi 150331 
afdboi 


Area forecast discussion 
National Weather Service Boise Idaho 
930 PM MDT sun Mar 14 2010 


Discussion...a high pressure ridge aloft continues to intensify 
over the region. The upper ridge axis was positioned from eastern 
Oregon northward to the Idaho Panhandle and Alberta. Latest 
satellite images and surface observations revealing high clouds 
streaming through the ridge axis for partly cloudy skies in most 
areas overnight. The 00z Boise radiosonde observation shows a deep layer of warming 
above 850 mb. Minimum temperatures tonight expected to be a good 5 to 8 
degrees warmer than last night. Current forecast in good shape...no 
updates planned. 


&& 


Aviation...just some high clouds over the area will be thick 
tonight...thinning on Monday. VFR conditions Monday. Light surface 
winds. 


&& 


Previous discussion...clear and cold again tonight with surface high 
pressure over our County Warning Area and northwesterly flow aloft on the front flank of 
approaching upper ridge. Sunny and warming beginning Monday as the 
center of surface high pressure shifts slightly east while the upper 
ridge axis comes overhead. Warming trend will continue into Tuesday 
when the upper ridge axis is east of US and southwesterly flow aloft comes 
in. Tuesday will be the warmest day so far this year with maximum temperatures 
55 to 65 in the valleys and upper 40s through 50s in the mountains. 
High clouds will increase Tuesday in Oregon zones ahead of a weak 
cold front...but Idaho zones will still be sunny. 


Long term...Tuesday night through Sunday...Tuesday night and 
Wednesday upper level ridge will be pushed east of the forecast area 
as a weak shortwave trough moves into the Pacific northwest. Main 
dynamics and precipitation with this upper level trough will be 
north of the forecast area but will keep small probability of precipitation over northern 
zones. Temperatures on Wednesday will cool to near normal as a weak 
cold front moves over the areas. Wednesday night and Thursday the 
upper level trough will move to the southeast as the ridge rebuilds 
along the West Coast. This will bring a cool northerly flow to the 
region. Again main dynamics and precipitation will be north and 
east of the forecast area but will keep small probability of precipitation over the higher 
terrain of the west central and Boise Mountains and dry over 
southeast Oregon. Thursday night and Friday models agree with a 
ridge continuing to build along the West Coast but differ in the 
placement of the axis of the ridge. Depending on where the ridge 
axis sets up will mean the difference between being dry vs wet. 
Will trend toward a model blend but will stay below climatology for 
Friday. For Friday night through Sunday models differ on the timing 
of the next upper level trough that will move into the West Coast. 
With low confidence in the models will trend probability of precipitation to near 
climatology with temperatures near normal. 


&& 


Boi watches/warnings/advisories... 
Idaho...none. 
Or...none. 


&& 


$$ 


Weather.Gov/Boise 


Discussion...gs 
previous discussion...lc 
long term....ja/dd 
aviation.....Prf