Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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914 FXUS63 KBIS 200800 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 300 AM CDT Fri Sep 20 2024 .KEY MESSAGES... - Expect low to medium chances (20 to 40 percent) for showers late this afternoon and into the night. The best chances will mainly be north of the Highway 200 corridor. - After warmer temperatures today, a cooling trend is forecast through the weekend and into early next week. Some areas of frost are possible Sunday morning across the west. && .DISCUSSION... Issued at 300 AM CDT Fri Sep 20 2024 Progressive low amplitude ridging will quickly cross the state this morning, giving way to southwest flow aloft ahead of an approaching trough from the west. Temperatures will be a bit warmer today with highs forecast to range from the low to mid 70s north to the low to mid 80s south. Winds will be lighter today out of the southwest, but some breezy conditions may hang around across the northwest. The upper trough axis will approach the Montana/North Dakota border this evening, along with increasing cloud cover. At the surface, low pressure will move into the southern Canadian Prairies with a cold front extending to the south. This cold front will cross the state from west to east through the night, shifting winds to out of the northwest. Synoptic forcing from the longwave trough will interact with the low and cold front, providing enough lift for some scattered showers (20 to 40 percent chance). The best chances will be across the north closer to the synoptic forcing, generally along and north of the Highway 200 corridor. While instability is forecast to be weak, RAP soundings are suggesting at least a couple hundred J/kg of MUCAPE across the north. So there will be at least low chances for a rumble of thunder or two. Most of the precipitation will move out to the northeast by late Saturday morning or early afternoon as the trough axis moves into the Red River Valley. Winds will be on the increase overnight and into Saturday morning behind the cold front. Most guidance is suggesting that strong pressure rises and strong cold air advection should filter in behind the front, along with steep low level lapse rates (especially for the time of day). All the ingredients are shaping up for a breezy to windy Saturday (winds out of the northwest). For now, it appears the strongest sustained winds will be up to around 27 mph with gusts to 40 mph. If guidance continues to increase, we could eventually need a Wind Advisory so it will be something to watch. It will also be much cooler behind the front on Saturday with highs expected to only be in the 60s across all of western and central North Dakota. Saturday night into Sunday morning should be coldest time frame of the forecast period. Winds will be on the decrease under a mostly clear sky as high pressure dominates the weather pattern. Lows are forecast to dip into the mid 30s to the lower 40s. Some lower 30s are not out of the question across the usual low spots over the southwest. Areas of frost will be possible by Sunday morning across portions of the west. We will be in northwest flow aloft through much of the day on Sunday as a ridge axis approaches from the west. Highs will be just a touch warmer with most areas still in the 60s. However, a few lower 70s may be possible across the west. Winds will also be much lighter on Sunday. The next trough moves through on Monday which looks to be dry for now. Highs will generally range from the mid 60s to the mid 70 on Monday and Tuesday with some upper 70s and lower 80s returning to the forecast by mid to late week as a higher amplitude ridge axis moves through the region. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 100 AM CDT Fri Sep 20 2024 VFR through the period. Calmer winds around 10kts from the southwest overnight with clear skies. High and mid level clouds then move in Friday with winds gusting near 20kts from the southwest. Slight chance of rain Friday night at most terminals, but with low confidence we left it out of the TAFs for now. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...ZH AVIATION...Smith