Area Forecast Discussion
Issued by NWS Pocatello, ID
Issued by NWS Pocatello, ID
994 FXUS65 KPIH 140343 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 943 PM MDT Thu Jun 13 2024 .UPDATE... Radar shows a couple storms north of the American Falls Reservoir that seem to be holding together. Updated forecast to continue to mention storms through midnight with slight chance of showers after midnight across much of the Snake Plain into the eastern Magic Valley. 13 && .PREV DISCUSSION... /issued 138 PM MDT Thu Jun 13 2024/ SHORT TERM...Tonight and Friday Afternoon satellite imagery once again shows not much in the way of clouds across the region. Have seen a few mid/high level clouds streaking across southeastern parts of the area but most of us area seeing clear blue skies. Temperatures have warmed into the 80s across the lower valleys with 70s across the higher terrain. Some valley locations could hit the 90s before all is set and done today. Hi-res CAMs show some potential for a thunderstorm or two to develop later today. Probabilities are quite low however (less than 15%) so the forecast doesn`t have any mention of any precip for most areas. This will be the warmest day we see for at least a week as changes are in store for eastern Idaho. We begin to see a few of those changes tomorrow as we start to feel the influence of an trough moving into the Pacific NW. The pressure gradient will tighten tomorrow and winds will begin to increase accordingly tomorrow. As is often the case, the Arco Desert looks to be the windiest spot and they`ll come close to Wind Advisory levels (30+ mph) but right now it`s too marginal to issue an advisory. Much of the Snake Plain and Magic Valley will see winds in the 15-25 mph range for a good portion of the day. More wind to come (and stronger on Saturday). Friday looks mostly dry again although some afternoon convection up around Island Park will be possible. Temperatures will be around 4-6 degrees cooler than Thursday but a much more drastic cooldown is still ahead. McKaughan LONG TERM...Saturday through Friday As low pressure scoots to our north, a very strong wind pattern develops Saturday. The strongest winds will be across the central mountains and over portions of the Magic Valley and Snake Plain. Probability forecasts show a 30-70% chance of exceeding 30 mph sustained across most of the Snake Plain and eastern end of the Magic Valley, and hitting 90-100% across the Arco Desert and along I-15 north of Idaho Falls. We similar percentages for gusts over 45 mph. That would put us solidly in WIND ADVISORY territory. We see a 30-60% chance for sustained over 40 mph and gusts over 55 mph across the INL and along 15 north of Idaho Falls, which is HIGH WIND WARNING thresholds. These trends seem to be holding, so the likelihood of some kind of wind headlines is increasing. While we could see a few early day showers, we should be dry in the afternoon. Saturday will be the WARMEST, until we reach the end of next week. This is due an area of low pressure developing and slowly swinging across our area early next week. This storm does involve some colder air, with Tuesday being the "coldest". We are talking highs in the valleys in the 50s/low 60s and 30s/40s in the mountains. Yes, that does mean some wet snow in the higher elevations. The latest forecast shows a 75%+ chance of measurable snow across the central mountains and along the Montana border, and a 20-50% chance farther south. This once again serves as a reminder that weather doesn`t always follow the calendar. We should quickly recover (since it is June after all) by the end of next week. Keyes AVIATION... Mid level clouds will continue to stream overhead. The question is whether we will see any precipitation or thunderstorms with any of this in the next 24 hours. We did keep VCSH in the TAFs (outside of SUN), which was put in by previous shifts. The chance is low but not zero by any stretch. We opted to not include VCTS, but again the chance is low but not zero. Gusty winds are possible with anything that develops. Outside of anything from storms, we are expecting an increase in wind tomorrow. Sustained wind of 15-25kts are possible for BYI, PIH and IDA, with gusts of 25-35kts possible. Keyes FIRE WEATHER... The hottest day of the next seven is today, with BLM land elevations reaching the 90s in the TFD and southern portions of the IFD. Afternoon humidity should get below 15 percent in a lot of low elevations in the central Idaho mountains and the northwest side of the two main BLM districts. An approaching trough that arrives on the weekend with a cold front will start affecting weather on Fri. While today wind will be light, on Fri the wind will spike upwards again, with the strongest wind occurring on Sat. Strong cooling brings back temperatures more like early to middle spring on Mon and Tue. Messick HYDROLOGY... A flood warning remains in effect for the Teton River at Driggs through Saturday and the Snake River at Heise until further notice. The latter will likely stay above flood stage into early next week. McKaughan && .PIH WATCHES/WARNINGS/ADVISORIES... None. && $$