Sunday, September20, 2020
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Marine Weather and Tides
Big Sky, MT

Version 3.4
NOTICE
8/26/2020 The 7 day forecast is taking about 5 seconds to load but it will eventually load. NOAA is still working on it.
8/18/2020 NOAA continues to have trouble. Wind guest will occasionally be left off graphs. I am working with NOAA to resolve the issue.
12/16/2019 NOAA is having trouble with requests that include wind gusts. I am posting graphs without wind gusts until it gets fixed.
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.

Sunrise 7:08AMSunset 7:26PM Sunday September 20, 2020 6:13 AM MDT (12:13 UTC) Moonrise 10:09AMMoonset 8:34PM Illumination 11% Phase: Waxing Crescent; Moon at 3 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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7 Day Forecast for Marine Location Near Big Sky, MT
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location: 45.26, -111.31     debug


Area Discussion for - Great Falls, MT
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FXUS65 KTFX 201145 AFDTFX

Area Forecast Discussion . UPDATED National Weather Service Great Falls MT 545 AM MDT Sun Sep 20 2020

SYNOPSIS.

A disturbance exiting northeast out of the region will take scattered showers on the Hi-Line with it, but it will keep breezy and gusty westerly winds over the area through the day. Otherwise, a broad high pressure ridge will keep the area dry with warming temperatures through mid-week. A disturbance will then bring potentially strong winds with mountain showers on Thursday.

DISCUSSION.

540 am Update to the Today period . Showers in the Havre area will be slower to decrease and move out of the area than previously expected, so have increased the shower coverage and kept it in the forecast through most of this morning. Coulston

Today through Tuesday . The disturbance responsible for the showers across North Central Montana overnight will continue to move northeast into Saskatchewan today, taking any lingering showers with it. However, the surface pressure gradient in the wake of its associated cold front will help bring breezy and gusty westerly winds down from aloft to the surface, and these winds will continue throughout the day as skies generally clear from the southwest. Wind gusts in the 30 to 40 mph range will be common over the plains, but gusts could reach 50 mph in some places along the Rocky Mountain Front. A broad high pressure ridge will then build into the area from the west overnight through Tuesday, which will bring a drying trend with warmer than normal temperatures to the area with lighter winds. However, a weak disturbance may bring a few light mountain showers on Tuesday.

Regarding the smoke that has lingered over the area for quite some time, this latest system has helped to at least significantly decrease it, as the rain helped to scour the particulates out of the air. Also, the change in direction of the winds aloft from southwesterly to more northwesterly has shifted the smoke that is aloft more south of the area. The flow aloft will shift back westerly tonight and more southwesterly again Monday into Monday night, which may bring back at least a smoke layer aloft. However, the weather pattern will be a bit more progressive over the next week or so, causing shifting winds aloft. As a result, there will likely not be a persistent period of southwesterly winds aloft bringing the smoke into our area as had previously happened. It looks like there will be periods of smoky conditions, but more persistent smoke will be limited to areas near ongoing fires. Coulston

Wednesday through next Sunday . A low pressure trough off the coast of Canada will gradually broaden as it moves southeast into western Canada, the Pacific Northwest, and eventually into Montana by Friday. The initial push of this trough will bring increasing westerly winds aloft and mountain showers for Wednesday into Thursday. A strong upper level jet streak is forecast to combine with associated mid level winds and a strengthening surface pressure gradient to potentially spread strong westerly winds over the area, especially over the plains. Forecast models differ somewhat on the exact strength of these mid level winds, but the stronger solution indicates the chance for High Wind criteria winds on the Rocky Mountain Front, and possibly farther out onto the plains. The jet streak will start to move southeast of the area into Friday, which will cause winds to decrease; however, this will likely allow the mountain showers to spread out onto the plains and into the southwest valleys Friday through Saturday, as temperatures cool to near or slightly below normal. These showers appear to be scattered at the most at this time, but will continue to monitor the evolution of this system for more widespread precipitation potential. The forecast models then indicate that the trough will exit the area on Sunday, continuing the near normal temperatures with a decrease in showers. Coulston

AVIATION. 510 AM MDT Sun Sep 20 2020 (20/12Z TAF Period)

Light to moderate rain associated with an exiting low pressure system in the KHVR area will keep low VFR/MVFR conditions there through 15Z or so. Otherwise, scattered to broken VFR clouds will gradually decrease throughout the day across North Central and Southwest Montana. Moderate mid level westerly winds will also cause low level wind shear and mountain wave turbulence across North Central Montana until the winds mix down to the surface through 16Z. Winds will decrease after 00Z, leaving mostly clear skies. Coulston

Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information.

NOTE: Amendments not scheduled for Ennis (KEKS) due to ongoing runway closure.

FIRE WEATHER.

Westerly winds in the wake of an exiting disturbance will be quite breezy at times today, especially over the plains, where 30 to 40 mph gusts will be common. However, temperatures have cooled to near normal, which will keep afternoon humidity over 30 percent, so critical fire weather conditions are not expected. High pressure aloft will then help warm temperatures back above normal through mid-week, which will cause afternoon humidity to fall into the 20 to 25 percent range in some areas. Winds will be fairly light during this period, but there is a potential for strong westerly winds to return Wednesday night into Thursday ahead of the next possible precipitating system, so there is a chance for near-critical fire weather conditions during that time period. There is some uncertainty as to just how strong those winds could be, so will continue to monitor the situation for now. Coulston

PRELIMINARY POINT TEMPS/POPS. GTF 69 44 75 46 / 10 0 0 0 CTB 66 40 70 43 / 10 0 0 0 HLN 68 41 75 46 / 0 0 0 0 BZN 68 38 77 43 / 0 0 0 0 WYS 61 27 70 31 / 10 0 0 0 DLN 63 38 73 44 / 0 0 0 0 HVR 70 44 75 44 / 90 10 0 0 LWT 66 42 75 46 / 10 0 0 0

TFX WATCHES/WARNINGS/ADVISORIES. None.

http://www.weather.gov/greatfalls


Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Bozeman, Gallatin Field, MT38 mi18 minNNE 310.00 miMostly Cloudy48°F43°F83%1017.1 hPa

Link to 5 minute data for KBZN

Wind History from BZN (wind in knots)
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Last 24hrS8S3SE5NW9W4N6NE7E8NE34SW8S11SE4E3CalmNW7NE4CalmCalmCalmE3CalmCalmNE3
1 day agoCalmCalmNW4NE3Calm4W3W5NE3CalmCalmS5SE5S6SE46SE5SW9
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2 days agoSE4SE3CalmCalmCalmSW3CalmCalmCalmCalmW4N4E3CalmSE3CalmW4NE4SE6CalmS4CalmSE3Calm

Tide / Current Tables for
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Tide / Current Tables for
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Weather Map
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GEOS Local Image of    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.
Link to Loop

Other links: Northern Pacific     Contential US     Full GOES-East
Ground Weather Radar Station Billings, MT
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