FXUS65 KPIH 091947

AFDPIH



Area Forecast Discussion

National Weather Service Pocatello ID

147 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



Trof moves on shore Monday and a cold front will have moved 

through Idaho Monday night/Tuesday. Will continue to have a 

threat for showers and thunderstorms but not as significant as 

Sunday. Highs drop to the 50s and 60s mountains and 60s to lower

70s valleys. It remains windy with 15 to 20 mph sustained winds

likely to continue. It will take several days for the trof to 

move through the state and will see showers and thunderstorms 

likely once again Wednesday and Thursday as the trof moves 

overhead then works east Thursday. Highs Wednesday only in the 

40s mountains and 50s valleys with snow levels dropping to 

around 7 thousand feet so will likely see some snowfall in the 

highest elevations. Highs Thursday in the 40s and 50s mountains 

and back into the upper 50s to mid 60s valleys with slightly 

drier conditions expected Friday with only a slight chance or 

chance of showers and highs again in the 50s to near 60 

mountains and mid 60s to near 70 in valleys. It will remain a 

bit breezy Tuesday through Thursday with 10 to 20 mph sustained 

winds expected through the period in the Snake River Plain.



&&



.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, especiallyclose 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