Marine Weather and Tides
10/9/2019 Updated the Marine Zones.
9/4/2019 Fixed the weather maps due to NOAA moving them.
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.
6/2/2019. Many thanks to a user for reporting an error on one of the Edit pages. The switch to PHP 7.2 caused many pages that previously worked to quit working. I fixed many but I still depend on users to report ones I missed. Please report errors HERE or send an email to me at L-36.com. Allen
|Sunrise 8:11AM||Sunset 4:45PM||Saturday December 7, 2019 2:22 PM MST (21:22 UTC)||Moonrise 2:50PM||Moonset 3:03AM||Illumination 83%|
7 Day Forecast for Marine Location Near Somers, MTHourly EDIT Help
Area Discussion for - Missoula, MT  (on/off)  Help NOTE: mouseover dotted underlined text for definition
FXUS65 KMSO 071524 AFDMSO
Area Forecast Discussion National Weather Service Missoula MT 824 AM MST Sat Dec 7 2019
UPDATE. A warm layer of air above the valley floors is producing conditions for light freezing rain this morning. Of particular concern is the Interstate 90 corridor between Missoula and Lookout Pass and Highway 200 from Ravalli to Heron. Although freezing rain will be light, slick roads are possible due to a light glaze of ice. We have issued a winter weather advisory to reflect these conditions. Roads will improve by late morning as the sun warms up surface conditions. However, snow will intensify over Lookout Pass late this afternoon and evening, producing another period of potential travel impacts late tonight into Sunday morning.
AVIATION. Fog has developed this morning across much of Western Montana, despite increasing clouds aloft, and is affecting visibility at KMSO and KGPI. Like yesterday, these aviation impacts are likely to linger throughout the morning but gradually show improvement around 07/1700 at both airfields. Light rain is likely to begin at KGPI later this morning, but not at KMSO until later tonight. But any significant obscuration is not expected until this evening at both airfields. KBTM and KSMN will remain free of significant weather issues until late Sunday morning at the earliest.
PREV DISCUSSION. /ISSUED 328 AM MST Sat Dec 7 2019/
DISCUSSION . Despite the steady increase in clouds and mainly mountain precipitation, most of the broader valleys will experience yet another unseasonably warm early December day. In fact, the snow level today will likely rise to around 5000 feet over much of North Central Idaho and Western Montana, in response to warm air advecting into the region from our southwest. This shift in the forecast towards a warmer solution, is somewhat significant with regards to the expected transition to snow later tonight and overall forecast snowfall totals. But certainly not enough to warrant adjustments to any of our presently issued Winter Weather Advisories. They all seem to handle the potential societal impacts quite well.
What has changed is the overall impression that the back door or southwesterly moving cold front will cross the Continental Divide and brush across NW Montana Sunday morning. The most reliable model data seems to suggest that the winds and cold air will be a bit delayed and likely not all that strong. As of right now it seems the strongest winds are likely to occur in Kalispell by mid/late Sunday morning and be generally back to light, northerly by early evening. While the Flathead Valley is likely to see little snow with this system, the same cannot be said for the West Glacier and Seeley/Swan Regions where 12 to 18 inches are likely throughout the higher terrain and generally 2 to 5 inches within the valleys.
The delayed, shallower push of cold air will make it across Flathead Lake during the afternoon, but likely not be sufficient to crest Evaro Hill into Missoula. Thus the Missoula Valley along with points generally south of I-90 will remain in the warm sector (think light rain or rain/snow mix) until late Sunday afternoon. This is when a weakening area of pressure, that's shifting south out of Canada all Sunday, will pass by Missoula and bring colder air to the rest of the area. It will bring about a transition of any remaining precipitation over to snowfall. But by this time it seems that only scattered light snow would be possible in the Missoula/Bitterroot Valley. In fact the delayed cold air has resulted in a general halving of forecast snowfall amounts for most of SW Montana. However, the surrounding higher terrain should still get some much needed snowfall with Advisories still applicable for the higher terrain and mountain pass travel. Showers will gradually reduce in coverage and intensity Sunday night, but likely still linger about the higher terrain into at least Monday.
As previously noted in yesterday's discussion, showers are possible on Monday. Forecast soundings suggest that very light freezing rain could develop, mainly from the Flathead and Mission Valleys, to the Glacier National Park region Monday morning. With northwest flow continuing into Monday night, showers will persist. Other areas may see patchy freezing fog develop both Monday and Tuesday mornings.
Temperatures will moderate by mid to late week back to normal and slightly above across the region. A wave will bring snow showers Wednesday morning, mainly over northwest Montana and portions of north central Idaho.
Moist westerly flow begins by Thursday, bringing the chance for precipitation area-wide. There is concern Thursday morning that light freezing rain could be a possibility in the valleys of central Idaho into western Montana, but at this time we opted not to add it to the forecast package due to low confidence. On the other side of the coin, mountain locations will finally experience an uptick in snow through at least Friday and maybe Saturday.
MSO WATCHES/WARNINGS/ADVISORIES. MT . Winter Weather Advisory from 3 PM this afternoon to 11 AM MST Sunday ABOVE 4000 FEET for the Bitterroot/Sapphire Mountains.
Winter Weather Advisory until 11 AM MST Sunday Lower Clark Fork Region.
Winter Weather Advisory from 3 PM this afternoon to 6 PM MST Sunday West Glacier Region.
Winter Weather Advisory from 2 AM to 6 PM MST Sunday Potomac/Seeley Lake Region.
Winter Weather Advisory from 2 AM to 6 PM MST Sunday Butte/Blackfoot Region.
ID . Winter Weather Advisory from 2 PM this afternoon to 10 AM PST Sunday ABOVE 4000 FEET for the Northern Clearwater Mountains . Southern Clearwater Mountains.
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|Kalispell, Glacier Park International Airport, MT||17 mi||28 min||WSW 3||10.00 mi||Overcast||38°F||35°F||89%||1008.9 hPa|
Link to 5 minute data for KGPI
Wind History from GPI (wind in knots)
|1 day ago||S||W||Calm||Calm||NW||W||Calm||Calm||W||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||SE|
|2 days ago||SE||SE||SE||S||S||S||NW||NW||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||Calm||W||NE||Calm||Calm||SW||Calm||Calm|
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GEOS Local Image of PacificNorthwest EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
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Wind Forecast for Missoula, MT (16,3,4,5)(on/off)  Help
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