093 FXUS63 KBIS 021148 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 648 AM CDT Fri Aug 2 2019 .UPDATE... Issued at 646 AM CDT Fri Aug 2 2019 Patchy dense fog has developed across portions of southwest and south central North Dakota. The fog should dissipate by around 9 AM MDT. Elsewhere, the thunderstorms that were over the James River Valley during the night have moved off to the east, while scattered showers continue over north central North Dakota. Models continue to struggle with the north central activity, as well as the low stratus deck over south central North Dakota. Updates to PoPs and sky were based on observational trends. && .SHORT TERM...(Today and tonight) Issued at 414 AM CDT Fri Aug 2 2019 A mid level low spinning over North Dakota is responsible for scattered showers and thunderstorms early this morning. The heaviest activity over the past couple hours has been centered over the James River Valley. Radar estimates indicate that 2 to 3 inches of rain have fallen over parts of eastern Dickey County over the past couple hours. Other scattered shower activity extends across north central North Dakota, which is not being captured by models. Also monitoring for potential fog development early this morning. Light winds, low dewpoint depressions, and recent rainfall for many areas, but there may be just enough cloud cover to prevent widespread fog from developing. The mid level low will meander into eastern South Dakota today, continuing chances for showers and thunderstorms. Despite the presence of around 2000 J/kg CAPE this afternoon, mid level lapse rates less than 6 C/km and deep layer shear less than 20 kts should preclude any severe threat. It may be worthing noting that several parameters are favorable for non-supercell funnel clouds/landspouts. However, the lack of a marked surface wind shift should mitigate this threat, although there could be numerous outflow boundaries present. Chances for showers and storms will diminish in the evening as the mid level low drifts farther away from the region. .LONG TERM...(Saturday through Thursday) Issued at 414 AM CDT Fri Aug 2 2019 The general synoptic pattern through the extended period calls for upper level ridging over the Rockies and longwave troughing over eastern North America. Several waves rounding the top of the ridge will bring shower and thunderstorm chances to the area at various times. Temperatures are expected to be near normal. The first chance for showers and storms will be Saturday. A mid level shortwave is forecast to move into North Dakota by the afternoon, and some models show convection out ahead of this feature. Farther to the west, a surface trough is forecast to lie in the vicinity of the North Dakota/Montana border by late afternoon. There are questions on whether there will be enough forcing for convective initiation along the surface boundary, but strong diurnal heating and subtle mid level height falls should weaken CIN. At this time, think storms would be isolated if they form. Instability and shear parameters would support a low end severe threat. On Sunday, a strong low pressure system is forecast to approach Hudson Bay, with a trailing cold front extending back all the way into North Dakota. This front will be the focus for another chance of showers and storms Sunday afternoon through Sunday night. Instability and shear will be stronger than Saturday, sufficient for storms to become severe. There may also be a heavy rain threat Sunday as storm motion vectors are forecast to be oriented nearly parallel to the boundary. Beyond the weekend, it looks a bit quieter for a few days, with active weather possible again by the end of the week. && .AVIATION...(For the 12Z TAFS through 12Z Saturday morning) Issued at 646 AM CDT Fri Aug 2 2019 Patchy dense fog will impact KDIK until around 14Z this morning. At KBIS, expect IFR ceilings until around 14Z. Think that the cloud deck will start to scatter out at that time, but an extension to IFR conditions may be needed. Aside from the fog/low stratus across southwest and south central ND this morning, VFR conditions are expected, though fog could redevelop towards the end of this TAF cycle. Scattered showers near KMOT this morning are not expected to cause significant aviation impacts. This afternoon, scattered showers and thunderstorms are forecast to redevelop over southeast ND, and may approach KJMS. Winds will remain south-southeasterly and light through the forecast period. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Hollan SHORT TERM...Hollan LONG TERM...Hollan AVIATION...Hollan