FXUS65 KPIH 091951

AFDPIH



Area Forecast Discussion

National Weather Service Pocatello ID

151 PM MDT Fri May 9 2025



.KEY MESSAGES...



- Near-record heat for Saturday



- Thunderstorms Saturday afternoon, Saturday night for most, 

  Sunday afternoon, Sunday evening, for some



- Lake Wind Advisory in effect for Saturday mid afternoon to

  evening, even stronger wind develops Sunday afternoon.



&&



.SHORT TERM /THROUGH MONDAY/...

Issued at 123 PM MDT Fri May 9 2025



The upper level ridge will continue tonight and into Sat,

keeping the atmosphere stable and wind light. But by Sat

afternoon the breakdown of this upper level ridge begins. First

will be an increase in the synoptic wind, then by mid-afternoon

the atmosphere will start to destabilize. While precipitation

will be light, expect some strong gusty wind due to the

thunderstorm outflow. The front causing the destabilization does

not arrive until after this period. On Sat afternoon and

overnight all Sat night, the entire forecast area is susceptible

to thunderstorms. By Sun afternoon, the area is more limited to

the eastern and southeastern highlands, with a nonzero risk in

adjacent Snake River plain areas. 



The much warmer than normal conditions will peak on Sat, with

temperatures in the lower to middle 80s for the Snake River

plain, thanks to continued southwest air flow and the clear

skies. Expect middle 70s to middle 80s elsewhere. The cloud

cover on Sun and Mon, however, start a cool down ahead of the

front. This will also be aided by afternoon precipitationn,

including thunderstorms. By Mon, expect a 10 to 15 deg F

cooldown from Sat afternoon over that three day period for

highs.



The final forecast challenge is what wind will be doing. Some

individual guidance suites are expecting wind in excess of 20

mph for Sat afternoon in the Snake River plain, while the NBM

averaged data was hovering around. So have boosted the NBM wind

some for Sat afternoon and evening. This has resulted in a six

hour time period for a Lake Wind Advisory over the American

Falls Reservoir on Sat/Sat night. With the approaching low, wind

should be even stronger on Sun/Mother's day, making for a risky

day to go boating on the Reservoir.



&&



.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...

Issued at 302 AM MDT Fri May 9 2025



Cool unsettled pattern continues through the remainder of the week 

as East Idaho remains under the influence of Pacific trough. Main 

portion of the closed low ejects across the state Tuesday into 

Wednesday, for what is likely to be the wettest stretch for most 

areas. The unsettled pattern continues into the remainder of the 

week under the influence of broad trough across the Pacific 

Northwest/Northern Rockies with several reinforcing shortwave 

features. While there are slight differences among the ensembles 

with respect to depth and timing of the features, overall consensus 

remains generally high. Temperatures start to rebound later in the 

week, but stay generally cool under the threat of continued showers 

and breezy winds. 



&&



.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...

Issued at 1127 AM MDT Fri May 9 2025



Dry VFR conditions with light winds below 10kts on tap for most of 

East Idaho for the 18z-18z time period. Recent runs of the high-res 

models have been trying to develop some convective activity S/SE of 

BYI for late this afternoon into early evening. Not having a lot of 

confidence in this development, especially close enough to

impact BYI, so will leave VCTS out of the forecast but shade 

cloud cover a tad lower during this time period, keeping VFR no 

CIGS. We start to see better chances for development affecting 

more terminals after 18Z tomorrow, so that would be a discussion

for the next forecast cycle.



&&



.PIH WATCHES/WARNINGS/ADVISORIES...

None.



&&



$$



SHORT TERM...Messick

LONG TERM...DMH

AVIATION...DMH