FXUS63 KFGF 201920 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 220 PM CDT Sun Sep 20 2026 .KEY MESSAGES... - Frost chance exists Monday night/early Tuesday for northwest MN. - With the exception of Wednesday night, a dry period ahead. && .DISCUSSION... Issued at 220 PM CDT Sun Sep 20 2026 ...Synopsis... Upper low currently rotating over WY will push out into South Dakota and Nebraska tonight, weakening and moving into the Upper Midwest tomorrow. Some high clouds from this system for our area, but all models keep most of the precipitation to our south. At the surface, center of high pressure over Ontario will move only very slightly east, allowing light east to southeast surface winds over our CWA. While can't completely rule out some fog formation tonight, it will be hampered by higher clouds and a little bit of mixing. Right now best chances are up against the escarpment or Turtle mountains where the southeasterly winds will bring some upslope. The upper low pulls off to the east and leaves blocky ridging over the region through Tuesday. Upper flow starts to become more southwesterly Wednesday, with one shortwave coming out into the Northern Plains late Wednesday and into Thursday. There is decent consensus on southwesterly flow with various weak shortwaves continuing into next weekend. Can't really pin down precipitation at this point, but temps look like they will be above seasonal averages. ...Frost chances for Monday night into Tuesday morning... With the upper low moving east of our area by the first part of the work week, clouds look to be decreasing for at least some period Monday night, and a bit drier air moving in from the east. Probability of temperatures below 36 degrees range from below 20 percent in most of the central and western CWA, but get up to around 40 to 50 percent along our far eastern border. Advisory level temperatures dropping into the mid 30s are possible, although much will depend on exact cloud cover trends. ...Next precipitation chances Wednesday night and Thursday... Shortwave trough moving into the western Dakotas Wednesday will progress quickly into the Great Lakes by Thursday. Instability is pretty weak at less than 500 J/kg, so severe is not expected although some thunderstorm activity is not completely out of the question. Main impacts look to be rain, with 40 to 60 percent probabilities of over a quarter of an inch in portions of our western and southern counties. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 1225 PM CDT Sun Sep 20 2026 Some IFR ceilings hanging around KTVF, but that should scatter out in the next few hours and other TAF sites have already gone VFR. Biggest question is if we will get fog redeveloping late tonight into Monday morning. Models are not very favorable, but performed poorly last night. Best chances the HREF has for fog probability and visibility less than half a mile are at KGFK and KBJI at 20 to 30 percent. Think there will be fog somewhere with light east to southeast winds, but confidence is low on where. For now have 2-3SM visibility in the TAFs tomorrow morning at KGFK and KBJI, but will likely adjust as fog develops or does not overnight. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ DISCUSSION...JR AVIATION...JR