FXUS63 KBIS 190627 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 127 AM CDT Tue May 19 2026 .KEY MESSAGES... - Lows tonight into Tuesday morning around 30 to 35 degrees, coldest in northwest North Dakota. - Near to below freezing temperatures possible again Tuesday night into Wednesday morning, except in far west central and northwest North Dakota. - Unsettled weather pattern develops mid to late week. Highest and most widespread chances (around 30 to 60 percent) for rain are Thursday through Friday. && .UPDATE... Issued at 127 AM CDT Tue May 19 2026 Current radar shows a few stray light rain showers or sprinkles meandering across western and central North Dakota. With this update we converted all precipitation mentions to a slight chance of sprinkles and greatly expanded the areal coverage this mention primarily throughout central North Dakota tonight through Tuesday afternoon. UPDATE Issued at 1025 PM CDT Mon May 18 2026 Showers have generally exited to the east of western and central North Dakota at the time of this mid evening update. Weak radar returns linger over portions of central North Dakota, though with such poor forcing only sprinkles are anticipated at this time. Otherwise, with clearing skies found upstream to the northwest of the forecast area, did opt to add some patchy fog to northwest for the early to mid morning. UPDATE Issued at 630 PM CDT Mon May 18 2026 Light rain continues across portions of south central North Dakota at the time of this early evening update, with sporadic reports of drizzle also found further to the west. Precpitation is generally expected diminish from west to east through the evening. More isolated showers will be possible across the west and south central overnight, though additional accumulation is would be light. Have tweaked the PoP grids in line with the latest CAM guidance. Will also need to evaluate the potential for additional fog development tonight, especially across the northwest where low stratus is expected to diminish the quickest. Overall, the forecast remains in good shape at this time. && .DISCUSSION... Issued at 223 PM CDT Mon May 18 2026 Current surface analysis places low over the upper midwest with notable frontal boundary stretching to the southwest through the central plains. High remains over southern Saskatchewan into central Montana. Upper level analysis places trough over Saskatchewan southward towards the central Rockies. Southeast flow over our area with some embedded short waves is resulting in broad shower activity over much of South Dakota into southeast/south central North Dakota. For tonight, ongoing showers will continue into this evening before departing to the east/northeast. In the meantime, surface high settles into the area, mainly western locations, with cool air continuing to slide in. This will result in sub freezing temperatures over parts of western and north central North Dakota, therefore a Freeze Warning has been issued. Further east, confidence is a little lower as to how cold it will get given the persistant cloud cover. With that said, lows look to dip close to or reach freezing, so have decided to go with a Frost Advisory for that area even though technically "frost" will not form, but sensitive plants could be damaged, especially if temperatures are a degree or two lower than forecast. Trough pushes east early Tuesday, with a low amplitude ridge passing over for Tuesday into Wednesday. Expect a gradual warm- up for high temperatures, but Tuesday night may see some freezing lows, mainly over our east given the high passing over and clearing skies. Next trough digs in over the western CONUS on Thursday with our flow shifting southwesterly before the system closes off and ejects to the northeast to close out the week. Greatest chances for precipitation come Thursday into Friday (about 30 to 60 percent chance). Warming trend expected going into the weekend with NBM temperature spreads being quite confident in seeing well above average temperatures by late weekend. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 127 AM CDT Tue May 19 2026 Expect mostly MVFR ceilings overnight, except in northwest North Dakota, lifting from west to east Tuesday morning and afternoon. A few light rain showers or sprinkles are possible through Tuesday afternoon, with no impacts to aviation expected. Winds will remain northwesterly around 5 kts in western North Dakota to 15 kts at KJMS through Tuesday afternoon, then become light and variable over central North Dakota and southeasterly around 10 kts in western North Dakota Tuesday evening into Tuesday night. && .BIS WATCHES/WARNINGS/ADVISORIES... Freeze Warning until 9 AM CDT /8 AM MDT/ this morning for NDZ001>005-009-010-012-017>020-022-031>033-040-041-043-044- 055>059. Frost Advisory until 9 AM CDT /8 AM MDT/ this morning for NDZ013-023-025-035>037-042-046>048-050-051-060>062. && $$ UPDATE...Hollan DISCUSSION...JJS AVIATION...Hollan