Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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487 FXUS63 KBIS 070614 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 114 AM CDT Fri Jun 7 2024 .KEY MESSAGES... - By daybreak there will be chances (30 percent) for showers across the northwest. Then for the afternoon, chances (40 percent) for thunderstorms over all but the far west and far north. - Isolated showers (20 percent chance for rain) are forecast for Saturday and Sunday. Chances for rain with thunderstorms increase for the start of the work week (back to 30 to 40 percent). - With high confidence it is expected to be on the cooler side for Sunday and Monday, then warmer for the middle of next week with high temperatures in the 80s. && .UPDATE... Issued at 100 AM CDT Fri Jun 7 2024 Current surface analysis shows high pressure centered over western North Dakota with a clear sky overhead. With the high center over the forecast area winds had decreased to light and variable (in direction). Temperatures were on track with expectations for the midnight to 1 am hour and so subsequently our forecast lows were also on track with no changes needed to that forecast. The first hint of our showers that are in the forecast for later today are appearing on radar north of Glasgow, Montana, in Saskatchewan. Movement was, as expected, to the southeast. UPDATE Issued at 927 PM CDT Thu Jun 6 2024 Winds have become light in most locations, although remain a little breezy in the north. These winds will become light over the next hour or two as well. All in all, the forecast remains on track. UPDATE Issued at 708 PM CDT Thu Jun 6 2024 Windy conditions persist in a few locations, although most areas have dropped below advisory criteria. In addition, winds will continue to rapidly diminish this evening. Therefore, have allowed the Wind Advisory to expire. Otherwise, mostly clear skies are present and the forecast remains on track. && .DISCUSSION... Issued at 348 PM CDT Thu Jun 6 2024 At the moment, North Dakota sits under northwesterly upper level flow, with a large trough digging across the Great Lakes to the east, and a very broad ridge positioned across the western CONUS. With lower surface pressure to the east, and higher pressure to the west, a somewhat strong pressure gradient oriented northwest to southeast also sits across the entire state, helping bring about some rather strong northwesterly winds to much of western and central North Dakota. Earlier model soundings suggested the potential for 40 to 50 kt winds atop the mixed layer paired with inverted-V profiles, which seems to have nearly entirely transitioned these winds to the ground at this point. Many reports of sustained northwesterly wind speeds in the mid to upper 30 mph range have been reported today, with some gusts approaching 50 mph, exceeding 50 mph in isolated instances. As such, we`ve continued our Wind Advisory, which goes until 7 PM CDT tonight, when winds are expected to decrease around sunset. There have also been some reports of these winds kicking up dust, most notably across the southern James River Valley, which could potentially reduce visibilities to a half mile at times. We`ve added in some patchy blowing dust to the forecast in this area as well, until the Wind Advisory ends. While wind speeds are approaching warning criteria, they`ve largely remained below, so we will continue with a Wind Advisory at this time. Otherwise, generally clear skies are expected, with some fair weather cumulus across the central and James River Valley areas through the daytime hours. Highs today are largely in the 70s, with overnight lows tonight in the 40s. Heading into Friday, the aforementioned ridge is expected to flatten out somewhat, as a quick moving shortwave trough drops southeast through the area. Due to the transient nature of this wave, chances for precipitation (mostly 20 to 40%) moves through the area from the northwest corner to the southern James River Valley essentially through the daytime hours. A small corridor of modest instability and buoyancy across the south central may bring about some thunderstorms for a few hours in the evening, though the chance for these becoming severe is near 0. Otherwise, highs on Friday are expected to range from the mid 60s in the north to the upper 70s in the south. Some areas in the far south may see temperatures climb into the 80s. Overnight lows are expected to remain largely in the 40s. Through the weekend, the upper level pattern does not change very much, and as such, the conditions across our area will be rather similar Saturday through Monday morning. With a trough positioned to our north, slowly descending south through Saskatchewan and Manitoba, we remain under northwesterly upper level flow. Northern portions of our area may see occasional sprinkles or showers, but for the most part, we are expecting drier conditions, with highs consistently in the upper 60s to mid 70s during this time. A relaxed surface pressure gradient will help keep winds reduced as well. All in all, it seems like it will be a rather quiet period of weather through Monday morning. Our next decent chances for precipitation arrives Monday through Tuesday, as the aforementioned upper level low descends south into the northern Great Plains. With ample forcing associated with this wave, we may see a large swath of 20 to 40% chances for showers and thunderstorms sweep across the state from west to east during this time. Tentatively, long range guidance suggests the potential for some strong storms associated with this wave, however confidence remains rather low. The confidence in this upper level setup in general is somewhat low as well, as the spread in NBM high temperatures also increases during this time. Following this precipitation, long range guidance suggests broad ridging across the western CONUS, building into the Plains and sitting there through the remainder of the week. As such, a warming trend is currently forecast, with highs ranging from the mid 70s to mid 80s by Tuesday and Wednesday. As mentioned before, the NBM spreads in high temperatures are somewhat large, so the confidence in the pattern progressing like this is still not set in stone, but in general, we can anticipate warmer temperatures and drier conditions through the second half of next week. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 100 AM CDT Fri Jun 7 2024 High pressure over western north Dakota will drift east as the overnight hours drag on. A weak surface trough oriented northeast to southwest will approach by daybreak Friday with an increase in wind speed and a shift in direction. Along with that will be isolated (20 percent) showers around KXWA through the morning. Showers will move east and south toward KMOT and KBIS into a more unstable atmosphere where isolated -TSRA will be possible. By late afternoon -TSRA will be possible in the KJMS area. For now TAFs reflect VCSH during a several hour window of time until we can better refine timing of when thunder might be possible, if at all at the actual TAF locations. Ceilings and visibility will remain VFR through the TAF valid period. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...JPM DISCUSSION...Besson AVIATION...JPM