Area Forecast Discussion
Issued by NWS Pocatello, ID
Issued by NWS Pocatello, ID
901 FXUS65 KPIH 282020 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 220 PM MDT Tue May 28 2024 .SHORT TERM...Today through Wednesday Night. Early afternoon satellite imagery shows a H5 shortwave trough lifting out of the Great Basin with radar imagery showing strong thunderstorms beginning to develop in and around the Magic Valley and WRN CNTRL Mountains. This trough will be the main driver of convection today which aided by 300-600 J/kg of SBCAPE, 20-40 kts of 0-6km shear, and steep 8-10 degree 700-500 mb lapse rates, will support the potential for strong downdrafts and dry microbursts, supporting gusts in excess of 50 mph. We have already seen a line of showers pass through the CNTRL Mountains earlier today which with no lightning, was able to produce 30-45 wind gusts, indicative of the convective environment today. CAMS remain in reasonable agreement on taking these storms currently in the Magic Valley NE and WRN CNTRL Mountains NE and across the Snake River Plain through this evening. With the HRRR model showing wind gust potential in that 50-60 mph range, this lines up well with the HREF probability of sustained winds greater than 30 kts sitting at 70-90% for the aforementioned area. As these storms decrease in intensity after sunset, a cold front will begin moving through SRN Idaho tonight into Wednesday which will support strong synoptic winds during the daytime hours in addition to keeping our isolated to scattered showers and storms going through the night into tomorrow. As a result in the uptick in daytime winds, have gone ahead with a WIND ADVISORY for the ERN Magic Valley, Arco/Mud Lake Desert, and Upper Snake River Plain which will be in effect from 6 AM to 9 PM for sustained winds 25-35 mph with gusts up to 55 mph. Given it is currently 83 degrees at the Pocatello Airport as of 155 PM, today will have marked the warmest day in 232 days or since early October as many of our climate sites also see 80 degrees for the first time this year today. These above normal temperatures will be short lived however as colder air settles in midweek behind this cold front with highs about 10-20 degrees colder in the 50s/60s for Wednesday. We are also monitoring the potential for FROST ADVISORIES across portions of the Snake Plain and ERN Magic Valley for Wednesday and Thursday nights given low temperatures especially further north and west, hovering in the low to mid 30s in the latest forecast each night. MacKay .LONG TERM...Thursday through next Tuesday. The long term will start very dry with temperatures well below normal on Thursday with with highs mainly in the 40s and 50s mountains and 60s valleys. Winds will be greatly diminished in the Snake River Plain but still breezy. Generally expect 10 to 20 mph sustained with gusts around 30 mph. Will see a warming trend Friday into Saturday. Highs will be in the 60s and 70s Friday and low elevations into the low 80s on Saturday. Strong zonal flow aloft may bring at least a slight chance of showers and thunderstorms Saturday night into Monday mainly in the central mountains and Upper Snake Highlands. Highs Sunday through Tuesday will be mainly 60s mountains and 70s low elevations so near or slightly above normal. With the stronger zonal flow aloft expect breezy conditions to continue Sunday through Tuesday with continuing 10 to 20 mph sustained winds with gusts over 30 mph in the Snake Plain. GK && .AVIATION...For the 18Z TAFS through 18Z Wednesday. An approaching cold front and upper level system will bring showers and thunderstorms into southeast Idaho this afternoon and tonight. For now have vicinity thunderstorms this afternoon and evening at all sites and showers through tonight into Wednesday morning as the system works east. Winds generally around 10 knots overnight but very strong outflow gusts near any thunderstorm. Winds will be much stronger Wednesday and expect sustained 20 to 30 knots at BYI, PIH, and IDA with higher gusts. So will have impacts the next two days at all sites. GK && .PIH WATCHES/WARNINGS/ADVISORIES... Wind Advisory from 6 AM to 9 PM MDT Wednesday for IDZ051>055. && $$