Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
184 FXUS65 KBOI 221543 AFDBOI Area Forecast Discussion National Weather Service Boise ID 943 AM MDT Sat Jun 22 2024 .DISCUSSION...Southwest flow continues to strengthen over the region today with mostly clear skies. This flow will bring breezy conditions this afternoon (gusts 15-25 mph), and Sunday afternoon with gusts of 20-35 mph. Today will be the warmest day of the year so far with some places exceeding 100F in the lower valleys. Temperatures will be around 15 degrees above normal today and on Sunday. The record high at Boise is 104F today, and 103F on Sunday. Most places are around a 10-25 percent chance of exceeding record highs on Saturday and Sunday. Slightly cooler temperatures on Monday as a system passes by to the north, enhancing the winds again. No updates to the current forecast. && .AVIATION...VFR. Mostly clear skies. Hot temperatures will bring high density altitudes. Surface winds: variable 10 kt or less. Winds aloft at 10kft MSL: W-SW 10-20 kt. KBOI...VFR. Mostly clear skies. Hot temperatures will bring high density altitudes. Surface winds: SE 5-10 kt shifting to the N-NW after 20Z. Sunday Outlook...VFR. Hot temperatures will bring high density altitudes. Surface winds variable 10 kt or less becoming W-SW 5-15 kt with gusts to 25 kt after 18Z. && .PREV DISCUSSION... SHORT TERM...Today through Monday night...Hot temperatures are expected through the weekend as a ridge of high pressure remains in place, driven by an approaching Pacific system set to reach the British Columbia coast tonight. This setup will bring the warmest temperatures of the year so far. The Treasure Valley has a 70-80% chance of hitting 100 degrees or more today. On Sunday, the chances slightly decrease to 40-70% as the ridge axis and the warmest air shift further east. These temperatures are 15-20 degrees above normal, though still a few degrees shy of record highs. Clear skies and dry air will allow overnight lows to drop into the low to mid-60s each night, helping to mitigate heat concerns. As the ridge axis moves east, southwest flow aloft will develop, bringing breezy conditions to the higher elevations starting Saturday and intensifying on Sunday, with wind gusts reaching 25-35 mph. In the lower elevations, winds will be lighter. A Pacific system with an associated surface cold front will pass through on Monday, bringing slightly cooler temperatures, with valley highs around the mid-90s. However, the air mass will remain too dry for any precipitation with the frontal passage. LONG TERM...Tuesday through Saturday...A much stronger Gulf of Alaska trough is expected to move inland late next week, potentially as early as Thursday. The majority of ensemble guidance (around 83% of the members) favors an early cold frontal passage on Thursday, while the remaining 17% favor a passage on Friday. Ahead of the trough, an upper-level ridge will re-amplify on Tuesday and Wednesday with its axis just to our east. This will lead to temperatures rising back into the mid to upper 90s, with a 30-50% chance of reaching 100 degrees in the Treasure Valley on Wednesday. The frontal passage, currently favored for Thursday, will bring a significant temperature drop of about 20-25 degrees, potentially resulting in below-normal temperatures on Friday. While the air mass will remain largely dry, there could be enough moisture across the West Central Mountains of Idaho for showers and thunderstorms on Friday. Winds will stay breezy as the trough moves through. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.twitter.com/NWSBoise DISCUSSION...KA AVIATION.....BW SHORT TERM...JDS LONG TERM....JDS