Marine Weather and Tide Forecast for Boise City, ID
 | Sunrise 6:11 AM Sunset 9:11 PM Moonrise 2:15 AM Moonset 1:44 PM |
7 Day Forecast for Marine Location Near Boise City, ID
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FXUS65 KBOI 210242 AFDBOI
Area Forecast Discussion National Weather Service Boise ID 842 PM MDT Tue May 20 2025
DISCUSSION
No updates to the forecast. Skies will clear tonight and winds will weaken. Wednesday will be mostly dry as we continue the warming trend under an upper level ridge.
Thursday through Saturday we are still expected a slight chance of showers and storms across the northern portions of our area, but the weak appears fairly weak, so a significant degree of uncertainty still exists about peak storm potential. The long term forecast appears very warm, about 10-20 degrees above normal with highs approaching 90 degrees in the Valley on Monday.
AVIATION
VFR and clearing skies overnight. Surface winds: W-NW at 10 to 15 kt with gusts to 20 kt, becoming light and variable overnight. Winds aloft at 10kft MSL: W 15-25 kt.
KBOI...VFR. NW winds 5-10 kts this evening before becoming light and variable overnight.
PREV DISCUSSION
SHORT TERM
Tonight through Thursday night
Northwest flow over the region today will be replaced by weak upper ridging on Wednesday. This will bring warmer temperatures and lighter winds under a more stable air mass. The ridge won't be in place long, as a trough pushes into the Pac NW coast late Wednesday.
Increasing clouds Wednesday evening will trend into showers late Wednesday night and Thursday as the shortwave lifts from s-central Oregon into central Idaho. It's an energetic wave in model guidance with a compact jet max accompanying it. Have introduced thunderstorms mostly across Baker County and mtns of w-central Idaho on Thursday. Current guidance shows the best overlap of thunderstorm ingredients across the northern Boise mtns and w-central Idaho mtns. A frontal passage will bring breezy W-NW winds with gusts of 25 to 40 MPH across open and elevated terrain Thursday afternoon/evening. Conditions quickly stabilize Thursday night as the wave is quick to exit the area.
Temperatures trend warmer through Thursday which will see near normal highs.
LONG TERM
Friday through Tuesday
Another upper-level shortwave trough will be moving in Friday afternoon into evening. In part due to its favorable timing during peak daytime heating, showers and thunderstorms and forecast on Friday. The NAM is by far the most aggressive with CAPE values around 700 J/kg, while the GFS and ECMWF keep CAPE values generally below 500 J/kg. Shear values largely depend on how the shortwave orients, but values of 30 kt are likely with 35-40 kt being the extreme. The coverage of this event is still up in the air, however the maximum of thunderstorm potential exists along the southern border of OR/NV and ID/NV. Snow levels will be around 7500-9000 ft MSL during this event.
Starting Saturday and persisting until Monday, a strong longwave upper-level ridge will build over the Desert Southwest through the Northern Rockies. This will begin a gradual increase of temperatures through the weekend and into Memorial Day. On Monday into Tuesday, the GFS, ECMWF, and Canadian all hint at a glancing blow from an upper-level trough that rides the ridge north away from our area. There is considerable difference between solutions late Monday into Tuesday between the ECMWF and GFS/Canadian, thus this will be the end of the discussion.
BOI WATCHES/WARNINGS/ADVISORIES
ID...None.
OR...None.
Area Forecast Discussion National Weather Service Boise ID 842 PM MDT Tue May 20 2025
DISCUSSION
No updates to the forecast. Skies will clear tonight and winds will weaken. Wednesday will be mostly dry as we continue the warming trend under an upper level ridge.
Thursday through Saturday we are still expected a slight chance of showers and storms across the northern portions of our area, but the weak appears fairly weak, so a significant degree of uncertainty still exists about peak storm potential. The long term forecast appears very warm, about 10-20 degrees above normal with highs approaching 90 degrees in the Valley on Monday.
AVIATION
VFR and clearing skies overnight. Surface winds: W-NW at 10 to 15 kt with gusts to 20 kt, becoming light and variable overnight. Winds aloft at 10kft MSL: W 15-25 kt.
KBOI...VFR. NW winds 5-10 kts this evening before becoming light and variable overnight.
PREV DISCUSSION
SHORT TERM
Tonight through Thursday night
Northwest flow over the region today will be replaced by weak upper ridging on Wednesday. This will bring warmer temperatures and lighter winds under a more stable air mass. The ridge won't be in place long, as a trough pushes into the Pac NW coast late Wednesday.
Increasing clouds Wednesday evening will trend into showers late Wednesday night and Thursday as the shortwave lifts from s-central Oregon into central Idaho. It's an energetic wave in model guidance with a compact jet max accompanying it. Have introduced thunderstorms mostly across Baker County and mtns of w-central Idaho on Thursday. Current guidance shows the best overlap of thunderstorm ingredients across the northern Boise mtns and w-central Idaho mtns. A frontal passage will bring breezy W-NW winds with gusts of 25 to 40 MPH across open and elevated terrain Thursday afternoon/evening. Conditions quickly stabilize Thursday night as the wave is quick to exit the area.
Temperatures trend warmer through Thursday which will see near normal highs.
LONG TERM
Friday through Tuesday
Another upper-level shortwave trough will be moving in Friday afternoon into evening. In part due to its favorable timing during peak daytime heating, showers and thunderstorms and forecast on Friday. The NAM is by far the most aggressive with CAPE values around 700 J/kg, while the GFS and ECMWF keep CAPE values generally below 500 J/kg. Shear values largely depend on how the shortwave orients, but values of 30 kt are likely with 35-40 kt being the extreme. The coverage of this event is still up in the air, however the maximum of thunderstorm potential exists along the southern border of OR/NV and ID/NV. Snow levels will be around 7500-9000 ft MSL during this event.
Starting Saturday and persisting until Monday, a strong longwave upper-level ridge will build over the Desert Southwest through the Northern Rockies. This will begin a gradual increase of temperatures through the weekend and into Memorial Day. On Monday into Tuesday, the GFS, ECMWF, and Canadian all hint at a glancing blow from an upper-level trough that rides the ridge north away from our area. There is considerable difference between solutions late Monday into Tuesday between the ECMWF and GFS/Canadian, thus this will be the end of the discussion.
BOI WATCHES/WARNINGS/ADVISORIES
ID...None.
OR...None.
Link to 1 hour of 5 minute data for KBOI
Terminal Aerodrome Forecast (TAF) for KBOI
Wind History Graph: BOI
(wind in knots)
GEOS Local Image of Pacific Northwest
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Boise, ID,
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