Area Forecast Discussion
Issued by NWS Pocatello, ID
Issued by NWS Pocatello, ID
553 FXUS65 KPIH 160950 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 350 AM MDT Mon Sep 16 2024 .SHORT TERM...TODAY THROUGH TUESDAY NIGHT... Folks...Fall is almost here! At least as far as the forecast is concerned. A series of low pressure systems remain on tap this week bringing widespread showers and thunderstorms, and much cooler temperatures. Today will be a last gasp of summer as high temps make a run at 75-80 for most lower elevation and valley population centers. A lull in shower activity is expected this morning through early this afternoon with some breaks of sun, before isolated to scattered showers and thunderstorms return. The atmosphere isn`t perfectly set up as either a dry-microburst or wet-microburst environment this afternoon/evening, but the HREF wind gust max does simulate some convective outflows/downdrafts in excess of 50 MPH (likely mostly coming from the HRRR), and forecast soundings hint at varying degrees of increasing shear as evening approaches with locales that see sunshine potentially building up 500-1000 J/kg of MUCAPE. Messy...but the right combination of ingredients all together in the right place could result in a strong to borderline severe storm. All things considered, strong wind gusts in excess of 50 MPH and heavy rainfall seem to be the top hazards with storms today. Tonight this activity will trend even more widespread, culminating Tuesday in scattered to widespread shower activity with a few embedded thunderstorms regionwide, and much cooler high temps only reaching the upper 50s to low 60s. Storm total QPF amounts are expected to reach 0.15 to 0.40 inches in lower elevations like the Snake Plain and Raft River area, and 0.50 to 1.00 inches across many of our mountain ranges...which should damper ongoing wildfire activity. While flooding is not expected to be a widespread threat, we will need to watch recent burn scars and any areas impacted by multiple thunderstorms (or training thunderstorms) for localized issues due to higher rainfall rates and totals. 01 .LONG TERM...WEDNESDAY THROUGH NEXT MONDAY... Next low in series rotates into the Great Basin Wednesday, then shifts east Thursday into Friday. Moisture could remain trapped around the low, which may be too far south to truly impact East Idaho however there is enough uncertainty to keep a chance of precipitation across the region both days. East Idaho remains under the influence of northwest flow into the weekend, with cool temperatures each day. There are a series of weak shortwaves that pass through the region by the weekend. The GFS and ECMWF have been trending drier, but the ensemble clusters still show potential for a deeper trough to develop similar to the systems early this week. Thus there is still a chance for some showers moving into the weekend. There is high confidence that temperatures remain cool for the entirety of the extended period, with highs generally in the 60s for lower elevations. DMH && .AVIATION... Showers and a few thunderstorms working through East Idaho early this morning. Should see precipitation gradually diminish through about sunrise, then a brief break for the remainder of the morning. Thunderstorms redevelop this afternoon, with gust potential over 45kts along with very heavy rain. Precipitation gradually becomes more widespread and heavier overnight. CIGS remain VFR overall, but stronger storms could briefly lowering CIGS and VIS to MVFR. DMH && .FIRE WEATHER... Moisture will continue to stream into East Idaho today with another round of thunderstorms. Some of the storms may be strong this afternoon and evening, with wind gust potential over 50 MPH and locally heavy rainfall. Precipitation becomes more widespread and heavier through the night tonight, and most areas in East Idaho appear to have a greater than 70% chance of wetting rain by sunrise Tuesday. 24-hr total precip by that time should fall generally between 0.1-0.35" of rainfall, but some locations could see more especially given thunderstorm influence this afternoon and evening. The rain continues into Tuesday, along with temperatures continuing to fall with highs only in the lower 60s for most lower elevation locations. Cooler unsettled conditions continue into Wednesday and Thursday as another low crosses the region. There is some potential for drying late in the week into the weekend, but there is also some uncertainty on the potential of another trough arriving by the weekend. What is confident however, is temperatures remaining seasonably cool for the remainder of the week. DMH && .PIH WATCHES/WARNINGS/ADVISORIES... None. && $$