Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
380 FXUS65 KBOI 060224 AFDBOI Area Forecast Discussion National Weather Service Boise ID 824 PM MDT Fri Jul 5 2024 .DISCUSSION...Breezier conditions than forecasted are being experienced this evening from Mountain Home through the Western Magic Valley, with gusts up to 33 MPH reported so far. The winds are expected to diminish by sunset. However, surface winds will increase again on Saturday as a shortwave and jet max move through the northwesterly flow, primarily affecting areas northeast of the forecast region. This will bring wind gusts up to 40 MPH across much of the area. Temperatures are anticipated to reach the upper 90s, with some lower valleys potentially hitting 100 degrees on Saturday. A persistent upper-level trough over the northern plains looks to keep the heat, with the upper-level ridge, primarily west of the forecast area through at least Sunday. This will delay the onset of the hottest temperatures until Tuesday across southeast Oregon, expanding into southwest Idaho by Wednesday. Nonetheless, temperatures across southeast Oregon and the lower Treasure Valley are expected to be high enough to warrant heat advisories through the weekend. Overall, guidance has lowered temperature projections and 500 mb heights significantly from previous runs. Maximum temperatures are still expected to exceed 100 degrees in the lower valleys from Monday through at least Thursday. However, ensemble forecasts for max temperatures have dropped by 2-4 degrees for Tuesday through Thursday, along with reduced probabilities of exceeding 110 degrees. Wednesday now shows the highest probability at around 20%, with the remaining days below 10% in Boise. Monsoonal moisture from the southeast Wednesday through Friday could further limit maximum temperatures. Despite this, conditions are still favorable for a prolonged heat event, which could be dangerous if not properly prepared for exposure to the heat. An update on winds for tonight and Saturday will be provided shortly. && .AVIATION...VFR and clear. High density altitude due to hot daytime temperatures will continue through next week. Surface winds: variable less than 10 kt overnight, then W to NW 10-20 kt with 20-30 kt gusts Saturday afternoon. Winds aloft at 10kft MSL: NW 15-25 kt. KBOI...VFR and clear. Surface winds: variable 3-6 kt overnight, becoming NW 8-15 kt with gusts around 20-25 kt after Sat/18Z. High density altitude due to hot daytime temperatures will through next week. Sunday Outlook...VFR and clear. High density altitude. Variable winds 10 kt or less in the morning, then NW 5-15 kt with gusts of 15- 25 kt in the afternoon. && .PREV DISCUSSION... SHORT TERM...Tonight through Sunday night...A strong upper level ridge will bring increasingly hot temperatures to the area through the weekend as it drifts slowly east. Initially off the coast, it will move inland by Sunday night. The Excessive Heat Watch has been changed to a Heat Advisory for Harney and Malheur counties, along with the lower Treasure Valley of Oregon, for Saturday and Sunday. Temps will warm up even more going into the long term, and the Watch continues for most areas through next week. Winds will increase tomorrow afternoon/evening, especially in far SE Oregon and from near Mountain Home south and east, with gusts 20-30 mph. Winds will be considerably weaker Sunday. LONG TERM...Monday through Friday...I know it is starting to sound like a broken record, but temps will continue to rise going into next week. The upper level ridge will continue to move slowly east, and will be centered over our area Tuesday and Wednesday. An Excessive Heat Watch continues for most of the area Monday through Friday, with Wed currently forecast to be the hottest day. Numerous daily records will be set, and several all-time-high records may be reached. It`s going to be a dangerous time for those without air-conditioning, and for those working outside. The watch will almost certainly be upgraded to a warning as we get closer in time. Multiple consecutive days of high heat take a cumulative toll on the body that can seriously endanger life. This is especially true for those with pre-existing health conditions, BUT AFFECTS EVEN FOR THOSE IN PERFECT HEALTH, if reasonable precautions are not taken. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Excessive Heat Watch from Tuesday afternoon through Friday evening IDZ011-013-028. Excessive Heat Watch from Monday afternoon through Friday evening IDZ012-014>016-029-030-033. Red Flag Warning from 3 PM to 9 PM MDT Saturday IDZ424-426. OR...Excessive Heat Watch from Monday afternoon through Friday evening ORZ061>064. Red Flag Warning from 3 PM MDT /2 PM PDT/ to 9 PM MDT /8 PM PDT/ Saturday ORZ636-637. Heat Advisory from noon MDT /11 AM PDT/ Saturday to noon MDT /11 AM PDT/ Monday ORZ061-063-064. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.twitter.com/NWSBoise DISCUSSION...JDS AVIATION.....SH SHORT TERM...SP LONG TERM....SP