Weather Service Report


795 
FXUS65 KPIH 201950
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
150 PM MDT Fri Jul 20 2018

.DISCUSSION...A low pressure disturbance over British 
Columbia will track eastward Saturday and Sunday. Winds aloft begin 
to turn more southwesterly tonight and bring more of the moist 
subtropical air north into Idaho. The amount of moist air has 
trended lower and expectations of thunderstorms on Saturday is a 
little less than previous forecasts. A few thunderstorms are expected 
to develop near the Bear Lake area this evening. The moist unstable 
air spreads northward tonight with a slight chance of a shower or 
thunderstorm developing around St. Anthony, Ashton, and Island Park 
Saturday morning. The South Central and Eastern Highlands will be 
favored for isolated thunderstorms Saturday afternoon. Westerly 
winds will begin driving this moist air into Wyoming Saturday night, 
but some unstable air may remain near the Idaho and Utah border area 
on Sunday. The high pressure ridge over New Mexico is expected to 
shift westward Tuesday and Wednesday of next week and this may bring 
some monsoon air up through Nevada to Idaho. That would open the 
door for afternoon thunderstorms. As for the ongoing warmer than 
normal temperatures, a little less could cover Saturday and Sunday 
may be just enough to keep the the 90 plus temperatures going, 
especially from Blackfoot southward and the Challis area. 
Temperatures measured at The Pocatello Region Airport are working on 
17 days of highs at or above 90F. The record is 22 consecutive days 
set back in 2000. RS  

&&

.AVIATION...VFR conditions will continue into Saturday. Expect a mid 
cloud deck to stream into the area from the south over night. Could 
see a few light showers around early Saturday morning with isolated 
thunderstorms possible in the afternoon.

Valle

&&

.FIRE WEATHER...A front will arrive on Saturday. This will create 
create breezy conditions across portions of fire zone 476 on 
Saturday afternoon. However, we expect wind gusts to remain just 
below critical levels except near ridgetop level where fuels are not 
quite critical. Humidity levels will be near critical levels as 
well. After coordination with central idaho fire dispatch will not 
issue a red flag warning for Saturday. Meanwhile, we are expecting 
monsoonal moisture to arrive from the south on Saturday. Models are 
showing some morning showers on Saturday with isolated to widely 
scattered thunderstorms developing across southeast idaho on 
Saturday afternoon. Seriously considered a fire weather watch for 
Saturday for zones 427 and 413. However, model consensus does not 
support enough areal coverage with only the GFS showing enough 
coverage for scattered thunder to support a red flag warning. Will 
not issue a fire weather watch for now, and will reevaluate Saturday 
morning. 

Valle

&&

.PIH WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

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