490 
fxus65 kpih 062014 
afdpih 


Area forecast discussion 
National Weather Service Pocatello Idaho 
214 PM MDT Sat Sep 6 2008 


Discussion...once again very little to change for this forecast 
package. Northwest flow remains in place with cumulus field stretched 
across northern tier zones. Weak shortwave drops through Montana 
during the day Sunday...and could continue to see weak showers 
over higher terrain along Divide. Thus left low probability of precipitation along border 
areas through Sunday. Cold front drops through forecast area Sunday 
night with increase in northeasterly surface gradient into Monday 
morning thus expecting breezy winds Sunday afternoon and possibly 
through the night. Models now showing weak transitory shortwave ridge 
for Monday. Tuesday wave still collapses ridge along Pacific 
coast...but models still having a difficult time deciding on how 
much...if any...moisture makes its way north into east Idaho. GFS 
not producing any quantitative precipitation forecast for Tuesday...but shows a significant 
increase in middle level moisture. NAM supportive...so added 
collaboration probability of precipitation to Utah and Wyoming borders. Upper trough takes 
its time dropping through Montana into Wednesday...and some 
uncertainty as to depth and strength. Given uncertainty in middle 
week...left rest of forecast alone. Dmh 




&& 


Aviation...VFR conditions expected for the next 24 hours. -Shra 
expected mainly along the Continental Divide which may cause a 
temporary reduction in vis/cig. Winds really pick up Sunday afternoon 
across the area with the next system moving along The Divide. Winds 
will switch to northwest across the northern half of the region 
while remaining more out of the west across the southern half. Gusts 
in excess of 25 miles per hour are forecast for much of eastern Idaho. Winds 
should subside tomorrow evening. Keyes 




&& 


Fire weather...northwest flow will dominate again Sunday with 
another system dropping across The Divide. Still only a few showers 
expected near the Montana and Wyoming borders. This system appears to 
have a lot more wind with it than previously forecast. Winds will 
switch to the northwest and pick up during the afternoon across northern 
fire districts while across the southern half of the region...they 
will remain more westerly but increase in speed. Wind gusts in 
excess of 25 miles per hour will be common over much of eastern Idaho. Relative humidity 
values should remain high enough to stay out of red flag criteria 
for areas closer to West Yellowstone and along the Wyoming border. 
Farther south and west...relative humidity values will be borderline with some 
areas likely getting into red flag criteria for a few hours Sunday 
afternoon and early evening. Will not issue any highlights right now due 
to borderline event...but will make sure future shifts keep an eye 
on this situation. More westerly flow aloft will dry the entire 
area out for the first part of next week. Winds will be lighter 
however. The next system will not affect the are until Tuesday night 
or Wednesday. Keyes 




&& 


Pih watches/warnings/advisories... 
none. 
&& 


$$