Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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756 FXUS63 KBIS 080606 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 106 AM CDT Sat Jun 8 2024 .KEY MESSAGES... - Isolated showers (20 percent chance for rain) are forecast for Saturday. High temperatures to remain near to slightly below seasonable normals. There is a 30 percent chance of showers Sunday night. - Widespread chances (20 to 50 percent) for showers and thunderstorms to be found Monday. - Cooler temperatures expected Sunday and Monday. How much cooler still remains uncertain. Moderate to high confidence remains for warmer temperatures during the middle of next week with high temperatures into the 80s. && .UPDATE... Issued at 100 AM CDT Sat Jun 8 2024 Light showers over the southeast, LaMoure, Dickey and McIntosh counties, continued to move southeast and will be out of the area by 215 am. Surface high pressure ridging into the west will result in decreasing clouds central and east as those showers move out. Winds were light and variable for the most part, except near showers were speeds were 10 to 15 mph. That too will decrease after the showers move out. UPDATE Issued at 834 PM CDT Fri Jun 7 2024 Showers continue mainly in the center through east central parts of the state. These showers will continue moving east through the evening hours. There are also scattered popcorn showers in southern Canada heading towards northern parts of the state. However, these will likely dissipate as the sun continues to set. No lightning strikes have been observed for about 45 minutes as of this time. A few more lightning strikes aren`t totally out of the question, though no instability is being analyzed on the mesoanalysis page. This suggests less than 250 J/kg of MUCAPE is present, and any limited instability that does remain will continue to decrease as the sun sets. UPDATE Issued at 646 PM CDT Fri Jun 7 2024 Previously quasi-stationary frontal boundary has steadily been sinking south and is presently over the southernmost tier of counties. A couple of weak thunderstorms had developed in eastern Adams and southern Grant counties. The former moved into South Dakota and the latter has weakened. It remains possible that a brief strong thunderstorm could develop in far southern ND, though is looking less and less likely. As the frontal boundary continues into South Dakota, any remaining threat for strong storms will diminish over the next hour or so. Otherwise, scattered showers continue in central North Dakota. Recently, there were a few lightning strikes in southern McLean County. However, with the lack of instability, any embedded thundershowers should be few and far between. These showers will continue working through to the east southeast and exit the forecast area late this evening, or shortly after midnight. && .DISCUSSION... Issued at 255 PM CDT Fri Jun 7 2024 A weak disturbance in northwest flow could still bring showers and thunderstorms through this evening. SPC maintains a Marginal Risk of severe weather in southcentral and portions of southwestern North Dakota through this evening. The threat for severe weather overall looks very isolated today. Some HRRR CAMS are showing an isolated stronger storm later this afternoon into this evening across these marginal risk areas. There is abundant shear in this area during this time period. The bigger concern though is the lack of instability. HREF ensemble data showing MUCAPE up to 500 J/KG. While surface based CAPE is higher in some instances, the elevated nature of today`s convection would be tough to tap into this. A quick change from easterly flow at the surface to westerly flow aloft could be adding some SRH and perhaps promote weak rotation in isolated storms, yet again this would require surface based storms. More looking into the elevated storm environment the hodographs become more straight. This could still help with hail production, especially given the high amounts of shear. The concern still remains the lack of instability. There is a weak warm front boundary setting up as well in these Marginal Risk areas. If a stronger storm can get going along this boundary and pulse up, then perhaps hail up to an inch in diameter and wind gusts up to 60 mph are possible. For now kept messaging sub severe as this is where our highest confidence currently resides given the lack of instability. Precipitation activity should diminish shortly after midnight tonight. Look for overnight lows to be in the 40s, and light winds tonight as they switch back to a westerly direction. A broad upper low then looks to linger in southern Canada for Saturday maintaining the near to slightly below normal temperatures across the CWA. The unsettled northwest flow could result in a few isolated showers Saturday, with the higher confidence areas coming in the north where a weak frontal boundary may help with lift. Instability lacks even more than today, thus left our mention of thunderstorms for Saturday. Northwest winds may increase slightly for Saturday, yet be below advisory criteria. Sunday still remains a day of uncertainty as temperature and precipitation chances will highly depend on how far south this cut off low can progress. Clusters are about 50/50 on the low`s location which brings quite the spread in temperatures. There is somewhat of consensus that below normal temperatures will be found. How cold will depend on this location. NBM may have raised slightly today compared to last night, although this may be the trend until more model consensus can be found. NBM also keeps Sunday mainly dry for the time being, again dependent on the lows placement. A wave moving across the Pacific North West could then lift across the area Sunday night through Monday. This will linger cooler temperatures, yet make the next chance for widespread showers and thunderstorms. There is a high amount of shear during this time period, although instability looks limited. The chance for severe weather perhaps will need to be monitored going forward given the amount of shear available. One last note for the weekend, cooler temperatures could also be found in the morning with perhaps some upper 30s possible Sunday morning. Ridging to flat ridging could then be found through mid next week. This westerly flow could bring some warming temperatures, with NBM placing highs in the mid 70s to mid 80s for much of the CWA. Flat ridging could promote a few weak waves in the flow and possibly bring a shower or thunderstorm at times. Predictability is low for this pattern at this time and left in NBM PoPs for now. Clusters then indicate perhaps a return to a broad trough or at least northwest flow pattern. This may slightly cool the temperatures and bring more chances for showers and thunderstorms. CSU-MLP putting in some slight chances for severe weather mid to late next week. These chances are isolated to scattered and will have to be monitored going forward. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 100 AM CDT Sat Jun 8 2024 South and east of KJMS -SHRA will continue to move southeast and be out of the area by 08/0715Z. Clouds there will then decrease with SKC expected over the entire forecast area by 08/09Z. During the day Saturday -SHRA will be developing but the coverage of them will be isolated. With relatively dry air at the surface, as surface high pressure ridges in from Montana, much of the rain will not be reaching the ground (Virga). With that, gusty winds as high as G20 knots could result with variable wind directions. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...JPM DISCUSSION... AVIATION...JPM