


Area Forecast Discussion
Issued by NWS Pocatello, ID
Issued by NWS Pocatello, ID
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
902 FXUS65 KPIH 182343 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 543 PM MDT Fri Jul 18 2025 .KEY MESSAGES... - Red Flag Warning in effect for the southern highlands for scattered thunderstorms and gusty outflow winds this afternoon. - Marginal risk for severe thunderstorms this afternoon over much of east Idaho with strong outflow winds as the main threat. - Critical or near critical winds and humidities across the Snake Plain and central mountains Saturday afternoon. && .SHORT TERM /THROUGH SATURDAY NIGHT/... Issued at 121 PM MDT Fri Jul 18 2025 Marginal risk of severe thunderstorms in place today with monsoonal moisture helping to fuel isolated to scattered development this afternoon and evening ahead of weak cold front. Steep lapse rates Widespread precipitable water > 0.75" in place for most of East Idaho with the exception of the Central Mountains, where values drop off to between 0.5-0.75". DCAPE across the southern highlands around 1200 J/kg will support gusty winds along with small hail, and localized heavy rainfall. HRRR has been consistent with supporting potentially long-tracked outflows across both the northern zones and southern highlands. Activity diminishes this evening, leaving locally breezy winds behind. Could see redevelopment of some showers into Saturday as the upper feature shifts through the region, but there is little agreement even among the high-res solutions, and the signal is washed out in the Blend. There is enough dry air upstream on the water vapor imagery, and HREF drops precipitable water significantly across the region into Saturday. Winds look to be stronger during the day Saturday particularly across portions of the Snake Plain, leading to new Fire Weather concerns for critical wind/humidity combinations. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 121 PM MDT Fri Jul 18 2025 Models and ensembles have remained consistent with development of a trough along/just off PacNW coast through the extended period. Flow aloft turns gradually more southwest through the period with East Idaho caught between trough and developing high pressure near the 4- corners region. Could see a few pulses of moisture work toward the region for an occasional isolated thunderstorm threat. Otherwise daytime highs stay relatively stable in the upper 80s/low 90s across the region. The warm and generally dry conditions will likely lead to additional Fire Weather concerns with breezy afternoon winds. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 522 PM MDT Fri Jul 18 2025 Thunderstorms will impact IDA and DIJ the next couple of hours. Variable outflow gusts around 25 to 35 kts are possible for IDA and DIJ the next couple of hours. Otherwise, winds will drop off overnight and skies will clear out. Look for breezy winds tomorrow afternoon with gusts of 20 to 30 kts likely for all TAF sites as weak, dry trough moves over our area. && .FIRE WEATHER... Issued at 121 PM MDT Fri Jul 18 2025 Scattered, mostly dry thunderstorms will impact Fire Weather Zones 427 and 413 today, where fuels are critical and the current Red Flag Warning remains in effect through Midnight tonight. Outside of those two Zones, isolated to scattered coverage is also forecast across Zone 411, and portions of 410 and 476. Storms will be capable of producing 40 to 50 mph outflows with more isolated gusts over 50 mph. Elevated fire weather conditions are anticipated across the Snake River Plain and portions of the eastern Magic Valley again tomorrow, for minimum RH and winds. There is a 50 to 70 percent probability of gusts over 30 mph across most of Zone 410, coinciding with RH widely ranging 15 to 20 percent. A Red Flag has been pre- coordinated with East Idaho for Zone 410, which will be issued following the expiration of the current RFW. The northern portion of Zone 425 is also expected to observe near critical to critical winds and RH tomorrow. There is some potential that conditions could be supportive of another RFW on Sunday, but winds look to be a bit lighter and RH slightly higher Sunday. && .PIH WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until midnight MDT tonight for IDZ413-427. && $$ SHORT TERM...DMH LONG TERM...DMH AVIATION...TW FIRE WEATHER...Cropp