FXUS63 KBIS 021438 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 938 AM CDT Fri May 2 2025 .KEY MESSAGES... - Dry with warming temperatures to end the work week through the weekend. - Southerly winds and low humidity values will result in near critical to critical fire weather conditions over parts of the area on Sunday. - Low to medium rain shower chances return Monday, with possibly a few thunderstorms. && .UPDATE... Issued at 938 AM CDT Fri May 2 2025 Areas of fog have expanded into south central North Dakota, although significantly reduced visibilities have been pretty transient and short-lived at most locations, with the exception of the northwest. We did expand and extend the Special Weather Statement until 11 AM. Fog seems to be the thickest along the leading edge of the very low stratus deck, extending from the northwest (around Williston) to the Dickinson/Morton County line. Will keep an eye on development but based on NDDOT travel cameras, there has been some improvement in the past 30 minutes or so. Made some adjustments to fog coverage, otherwise no changes with this update. UPDATE Issued at 643 AM CDT Fri May 2 2025 Areas of fog remain over parts of western nudging into central North Dakota. Latest webcams and observations show that it has become dense in some spots, but this remains hit and miss. Therefore, have issued a Special Weather Statement to address this running through the early morning hours. Otherwise, quiet weather remains over the region. && .DISCUSSION... Issued at 400 AM CDT Fri May 2 2025 Current surface analysis places low from the upper midwest through the Great Lakes region, with high nudging eastward into the northern plains to the lee of the central Rockies. Upper level analysis places trough over the upper midwest with ridge over the northwestern CONUS. Over our area, shower activity has finally diminished on the back side of the trough, though some low clouds and fog have developed primarily over northwest into north central North Dakota. For today, fog should diminish as the morning goes on, but clouds may be a bit more reluctant to dissipate, most notably over eastern locations. Otherwise, a rather quiet day is on tap with temperatures around average. As we go through the weekend ridge pushes east sliding over the Rockies into the Plains. This will result in a warming trend and dry conditions. Humidity values are forecast to drop into the upper teens to lower 20s on Saturday, with southerly winds around 10 to 15 mph. On Sunday, humidity values in the 20s are expected over much of western and central North Dakota, while southerly winds will be stronger, around 20 to 30 mph, which leads to increasing fire weather concerns and possible critical fire weather conditions over parts of the area. On Monday ridge pushes off to the east and deep trough over the western CONUS continues to push east, closing off over its southern end. South to southwesterly flow remains over our area through the day while a boundary gradually settles through. This will bring low to medium chances for showers, and with modest instability in place, possibly a few thunderstorms. Pattern gets a bit messy as we get into the middle into the end of the week as closed off low lifts into the central CONUS. For now expect most precipitation to stay generally south of our area though some uncertainty remains in place. Temperatures look to remain seasonably mild. && .AVIATION /12Z TAFS THROUGH 12Z SATURDAY/... Issued at 643 AM CDT Fri May 2 2025 Widespread MVFR to IFR ceilings have spread through much of western into central North Dakota this morning. Expect this to improve later this morning through the mid-day hours. In addition, some areas of fog have also developed over western into parts of central North Dakota, resulting in occasional LIFR to IFR visibility. This will improve later this morning. After the fog dissipates and ceilings improve, VFR conditions will prevail. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Jones DISCUSSION...JJS AVIATION...JJS