textproduct: Boise

DISCUSSION

Showers were winding down this evening with just a few lingering showers, but will redevelop over the high terrain Thursday afternoon due to a large upper trough over the interior west. There is also a slight chance (< 20 percent) of afternoon thunderstorms in central Idaho. Temperatures may be a degree or two warmer, but still several degrees below normal. No updates.

AVIATION

Mainly VFR. Scattered showers after 03/18Z will create periods of MVFR/IFR, mainly over the West Central ID Mtns and near the NV border. Showers will be capable of graupel, isolated lightning, and outflow winds up to 30 kt. Snow levels 3500-4500 feet MSL. Patchy valley stratus/fog through Thursday morning will create periods of IFR/LIFR, mainly around KMYL, KTWF, and KJER. Mountains obscured at times. Surface winds: W-NW 5-15 kt with gusts around 25 kt. Winds aloft at 10kft: N-NW 10-20 kt.

KBOI...Generally VFR. Scattered showers developing Thursday afternoon over Boise foothills. Mountains obscured in precipitation. Surface winds: NW 8-14 kt with gusts around 20 kt by this afternoon.

PREV DISCUSSION

SHORT TERM...Tonight through Friday night...The weather will remain cool and unsettled through Thursday under an elongating trough. Shower development will initiate off higher terrain Thursday afternoon, fed by daytime instability. Similar to recent days, lower elevations will see shallow cumulus buildups with any low threat of precipitation (<10%) coming from activity exiting the mtns on northerly flow. An upper ridge builds in from the coast on Friday bringing dry conditions to the region. Temperatures warm from around 5 degrees below normal Thursday, to around normal on Friday. Winds will remain gusty on Thursday, mostly along the I-84 corridor, relaxing some on Friday as the flow aloft weakens.

LONG TERM...Saturday through Wednesday...A deep upper level ridge will build over the Western US, bringing warm, above normal temperatures, and dry conditions through Monday morning. Highs will be around 3-5 degrees above normal, with overnight lows still in the 30s in the valleys through the weekend. A shortwave trough will move in on Monday afternoon, bringing widespread showers and cooler temperatures on Tuesday. Snow levels will drop to around 5000-6000 feet on Tuesday, with minimal accumulations anticipated. A ridge will then quickly build back in on Wednesday, bringing another push of warm and dry weather with highs in the Treasure Valley approaching near 70 by Wednesday. This might be the end of the overnight frosts in the valley for the time being, with long range models favoring above normal temperatures through the month.

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AVIATION...Mainly VFR. Scattered showers after 02/17Z will create periods of MVFR/IFR, mainly over the West Central ID Mtns and near KBKE-KBNO and the NV border. Showers will be capable of graupel, isolated lightning, and outflow winds up to 30 kt. Snow levels 3500- 4500 feet MSL. Patchy morning valley fog tomorrow will create periods of LIFR/IFR, mainly around KMYL. Mountains obscured at times. Surface winds: W-NW 5-15 kt with gusts around 25 kt. Winds aloft at 10kft: N-NW 10-20 kt.

KBOI...Generally VFR. Scattered showers developing this afternoon over Boise foothills. A 10% chance of MVFR rain/graupel showers hitting KBOI terminal this evening. Mountains obscured in precipitation. Surface winds: NW 8-14 kt with gusts around 20 kt by this afternoon.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None. OR...None.