####018004658#### FXUS65 KBOI 160313 AFDBOI Area Forecast Discussion National Weather Service Boise ID 913 PM MDT Thu May 15 2025 .DISCUSSION...A well defined shortwave trough is pushing into the Pac NW this evening. Radar imagery is revealing widespread light showers across western OR/WA with isolated signatures across eastern Oregon. Best chance for precipitation remains is in the overnight and early morning hours across SE Oregon and SW Idaho. Showers will linger in the mountains through Friday afternoon. The current forecast has it well handled, so no update for this evening. && .AVIATION...VFR through early overnight hours. MVFR conditions possible (20-40%) from low ceilings with rain showers as they move through SE OR from 05Z-14Z, enter SW ID around 10Z and clear out of lower elevations by 18Z. Precipitation chances linger in higher elevations through 00Z Saturday. Cloud cover increasing from west to east. MVFR conditions and mountain obscuration possible in showers. Surface Winds: W-NW 5-12 kt gusting up to 20 kt near KTWF/KJER during afternoon. Winds aloft at 10kft MSL: W-NW 10-20 kt. KBOI...VFR. MVFR conditions possible (20-35% chance) with rain showers during morning. Ceilings to rise during afternoon. Surface winds: W-NW 3-6 kt overnight increasing to 8-13 kt afternoon. Weekend Outlook... VFR to MVFR and a slight chance of IFR Saturday with widespread precipitation and isolated thunderstorms, especially during the afternoon hours. Mountains obscured at times. Snow levels 6500-8000 ft MSL Friday, 7000-8500 ft MSL Saturday. Precipitation moves out from west to east Sunday, with improving conditions (mostly VFR, but mountain obscuration still likely). Surface wind increasing to 15-30 kt gusting up to 25-40 kt Sunday. Snow levels falling to 5000-7000 ft MSL Sunday. && .PREV DISCUSSION... SHORT TERM...Tonight through Saturday night...There is still some residual moisture from the upper trough to our east, resulting in isolated showers in the West Central Mountains east of McCall through this evening. The next (weaker) upper trough resides in a northwest flow aloft, currently situated near the PacNW coast. Showers with the trough spread across SE Oregon tonight and SW Idaho on Friday, although precip amounts will be light and favor the higher elevations. Little to no rainfall is expected in the Snake River Plain. There is about a 6 hour dry period Friday evening after the Friday trough departs and the next (stronger/wetter) trough spreads widespread showers into the region late Friday night through Saturday. Precip totals of around a quarter of an inch in the valleys and a quarter to half inch in the mountains are expected. Locally higher amounts are possible, mainly in the mountains. Instability with the system could lead to thunderstorms, with chances generally in the 15 to 30 percent range. Temperatures remain 5 to 10 degrees below normal. The coolest day will be Saturday with highs mainly in the 50s to lower 60s. LONG TERM...Sunday through Thursday...Precipitation continues Sunday as the upper trough closes off a cut-off low over our area. Precipitation chances range from 60-90% across higher terrain and from 20-40% in lower elevations, generally increasing as you move from eastern Oregon into Idaho. With the cold core overhead and some instability (<100j/kg of CAPE) building in Sunday afternoon, thunderstorms aren't out of the question with a 20% chance across most of our area. Winds increase and approach advisory criteria as a pressure gradient tightens across our area. Sustained winds of 20-30 MPH gusting up to 40 MPH within the Snake Plain. Precipitation makes its way out of our area through Monday morning as a weak upper level ridge builds in. Tuesday afternoon this ridge breaks down into a more zonal flow regime. While most of our area will remain dry through Thursday, shortwaves embedded in the zonal flow may bring periods of higher precipitation chances across higher terrain. Temperatures increase from 10 degrees below normal on Sunday, making it to near normal come Thursday. Snow levels follow a similar trend, increase from 4-5 kft on Sunday to 7-9 kft on Thursday. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise DISCUSSION...DG AVIATION.....CH SHORT TERM...BW LONG TERM....NF ####018004204#### FXUS65 KFGZ 160313 AFDFGZ Area Forecast Discussion National Weather Service Flagstaff AZ 813 PM MST Thu May 15 2025 .SYNOPSIS...Warm temperatures continue on Friday with cooler weather returning over the weekend and into early next week. A storm system over the weekend and into Monday will bring chances for showers and gusty southwest winds. && .UPDATE...The current forecast remains in good shape. Look for fair weather overnight with a near repeat of Thursday's weather on Friday. && .PREV DISCUSSION /558 PM MST/...Friday...Dry conditions continue with near average temperatures expected. Winds will be primarily out of the west to southwest and around 5-15 mph with afternoon gusts around 20-25 mph. Saturday through Monday...A deepening trough across the Great Basin will bring increasing winds through the weekend. The winds on Saturday will increase out of the southwest to 10-20 mph with gusts 25-35 mph, increasing to 15-25 mph with gusts 30-40 mph on Sunday. It will still be fairly dry on Saturday, and with the very dry conditions across eastern parts of the forecast area, we could see some fire weather concerns. The strongest winds look to be more over western and northern areas while the driest conditions look to be over eastern areas. Still looks marginal but near critical to critical fire weather conditions are expected. The approaching trough will drag in some cooler air on Saturday as a cold front moves through but the colder air arrives for Sunday and Monday as the trough redevelops on the western side and dives down through the state. We should also see moisture increasing on Sunday which may allow for some showers and isolated thunderstorms (even some snow showers across the higher elevations) late Saturday through Sunday. Areas along and north of the I-40 corridor look to have the best chances for a shower. The increasing moisture should help to tamp down the fire weather concerns. Though the southern portions of Apache and Navajo counties will still have near critical conditions as winds will be gustier on Sunday. As the secondary trough pushes into the region, we will see another influx of moisture to the region and more chances for showers and thunderstorms, especially along and north of the Mogollon Rim. An active start to the week for sure. As the second trough exits the region late Monday, we should see a rather quick recovery across the state. Temperatures will warm to near average by midweek and then 5-10 degrees above average for the second half of the week. Winds are expected to become lighter through the rest of the week. && .AVIATION...Friday 16/00Z through Saturday 17/00Z...VFR conditions, no precipitation expected, smoke could reduce visibility near and downwind of Greer (east Arizona) and Blind fires (SE of KLFG). Winds light and variable or terrain driven over night, becoming SW 5-15kts, gusts to 20kts between 15-18Z Friday. OUTLOOK...Saturday 17/00Z through Monday 19/00Z...VFR conditions, no precipitation expected until 12Z Sunday, mainly north of I-40, then scattered rain showers. Smoke could reduce visibility near and downwind of wildfires. Winds Saturday SW 15-20kts, gusts to 30kts. On Sunday winds increase SW 20-25kts, gusts to 40kts. && .FIRE WEATHER...Friday through Saturday...Dry conditions will continue with minimum RH values mostly below 15%. Southwest to west afternoon winds 10 to 20 MPH Friday. Southwest winds increase on Saturday 15 to 20 mph gusting between 25 and 35 mph. Near critical fire weather possible Saturday. Sunday through Tuesday...Cooler, windy, and chances for showers on Sunday and Monday. Southwest winds 15-20 mph gusting between 30 and 40 mph on Sunday, becoming lighter westerly winds on Monday. Warmer, less wind, and drier on Tuesday. && .FGZ WATCHES/WARNINGS/ADVISORIES...None. && $$ PUBLIC...McCollum/Meola AVIATION...Bernhart FIRE WEATHER...Bernhart For Northern Arizona weather information visit weather.gov/flagstaff