Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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157 FXUS63 KBIS 042115 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 415 PM CDT Tue Jun 4 2024 .KEY MESSAGES... - Strong west to northwest winds are expected during the daytime hours across western and central North Dakota this afternoon through Thursday. - The strongest winds are expected in southwest North Dakota Wednesday morning and afternoon with gusts up to 55 mph. - Near to slightly below normal temperatures with mostly dry weather through this weekend. && .DISCUSSION... Issued at 409 PM CDT Tue Jun 4 2024 Nearly-stacked low pressure is analyzed over southeast Saskatchewan this afternoon. This low is forecast to slide into Manitoba through Wednesday as a strong upper jet/vort max digs underneath into North Dakota. The main concern with this system for our area is strong winds, mostly driven by the pressure gradient force. For the rest of this afternoon, the strongest winds will be focused over northwest North Dakota, particularly at higher terrain locations such as the Williston Airport. Later tonight, the approaching upper jet streak will induce a low level jet with northwest winds around 50 kts. This LLJ is forecast to pass over southwest North Dakota Wednesday morning. Multiple deterministic model soundings from Bowman to Lemmon, SD show downward momentum transfer potential of 50-60 kts, with the the top of the mixed layer possibly building closer to 700 mb. However, there are several limiting factors that could keep the strongest winds just below warning criteria of 40 mph sustained and 58 mph gusts, including the lack of strong surface pressure rises and low level cold air advection, as well as the earlier time of day for the core of the strongest winds aloft. HREF mean 10 m winds and gusts are also just below warning criteria. Confidence is therefore not high enough for a High Wind Warning, though a few gusts to 60 mph both spatially and temporally seem plausible. Elsewhere across western and central North Dakota, confidence is high in northwest winds increasing to 30-35 mph on Wednesday, with gusts up to 45-50 mph. A Wind Advisory has been issued, with a 5 AM MDT start time in the southwest, and 10 AM CDT start time elsewhere, ending for all locations at 9 PM CDT Wednesday evening. Aside from the wind, there are no other noteworthy items in the forecast for Wednesday. A few morning showers are possible in the southwest, and isolated afternoon showers could develop from the Turtle Mountains to the Devils Lake Basin. Highs on Wednesday are forecast to reach the lower to mid 70s. The synoptic pattern will transition to northwest flow over the Northern Plains on Thursday as a trough digs into the Great Lakes region. Another day of strong northwest winds is likely across northern and eastern North Dakota as high pressure building upstream maintains a strong pressure gradient. The northwest flow pattern is forecast to continue into the weekend, which could include the passage of a stronger shortwave on Saturday or Sunday. Such a feature would likely introduce chances for rain into the forecast, but ensemble spread and forecast time range supports maintaining a mostly dry forecast from Thursday through the weekend. For early to mid next week, there appears to be a variety of solutions in ensemble data sets that eventually transition to mean ridging over the central CONUS. This keeps forecast confidence low on rain and thunderstorm chances, but all ensembles show a warming trend to above normal by the second half of next week. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 118 PM CDT Tue Jun 4 2024 VFR conditions are expected through the forecast period. Light rain will remain possible at KJMS until mid afternoon. Westerly winds around 15-25 kts with gusts around 25-40 kts will continue through the afternoon, strongest in northwest North Dakota. Wind speeds will diminish to around 10-15 kts later this evening and tonight. Stronger westerly winds are then expected for Wednesday, with sustained speeds around 25-30 kts and gusts to 35-45 kts. The strongest winds on Wednesday are expected in southwest North Dakota. A period of low level wind shear concerns is expected at KMOT late tonight.&& .BIS WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 8 PM CDT /7 PM MDT/ this evening for NDZ001-002-009-010-017. && .BIS WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 8 PM CDT /7 PM MDT/ this evening for NDZ001-002-009-010-017. Wind Advisory from 10 AM CDT /9 AM MDT/ to 9 PM CDT /8 PM MDT/ Wednesday for NDZ001>005-009>013-017>023-025-034>037-042- 045>048-050-051. Wind Advisory from 5 AM to 8 PM MDT Wednesday for NDZ031>033- 040-041-043-044. && $$ DISCUSSION...Hollan AVIATION...Hollan