633 FXUS63 KFGF 020255 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 855 PM CST Sun Dec 1 2019 .UPDATE... Issued at 855 PM CST Sun Dec 1 2019 Fog has expanded and lowered across the Devils Lake basin and thus have issued a dense fog advisory through 3am. On the MN side of the valley some patchy fog has developed as temps have plummeted to single digits above and below zero over the fresh snowpack with the light winds. Cloud deck is expected to begin to move east as SW winds develop on the backside of the departing SFC high. Clearing line is expected to reach the western edge of the FA in the 3 to 6am time frame. UPDATE Issued at 605 PM CST Sun Dec 1 2019 Went a head and expanded the mention of fog and increased sky cover with stratus deck slowly spreading east approaching the northern valley. Also did up temps across much of E ND with prolonged cloud cover overnight. Fog has generally been 1 to 4 miles upstream with the exception across the Langdon bowl were the SFC ob has been a quarter mile or less. && .SHORT TERM...(This evening through Monday night) Issued at 250 PM CST Sun Dec 1 2019 Cloud cover and fog tonight will be the main headaches for the period. Upper low over the Great Lakes will continue to pull eastward overnight. The weak surface high extending from Manitoba into SD will move southeastward into MN tonight. Satellite loop and obs show this is more of a dirty high with trapped low level moisture bringing some fog and low clouds to much of western and central ND currently, including parts of the Devils Lake Basin. Winds will begin to pick up from the south to southwest later tonight across eastern ND as the surface high moves east, with warm air advection over cold snow covered ground. Think that the stratus and advection fog will move eastward further into our CWA as the night goes on. Not super confident on what will be stratus and what will be fog, so kept all mentions patchy for now. The warm air advection and winds will also keep temps in the low teens in our northwestern counties, while light winds and clear skies on top of snow will bring readings to near zero in west central MN. Tomorrow, a shortwave moving through southern Canada will push the surface trough axis into the Red River Valley. There should be at least some sunshine by the end of the day in addition to warm air advection, so continued with highs in the 20s to low 30s. The weak shortwave will continue through Monday night. A couple of ensemble members bring some very light precip with this system, including the GEM and operational ECMWF. However, even these wet outliers have been trending drier, so will keep the blended solution of no POPs for now. .LONG TERM...(Tuesday through Sunday) Issued at 250 PM CST Sun Dec 1 2019 For much of the work week, a mostly quiet weather pattern develops for the Northern Plains with little to no impacts expected. Through next weekend, the forecast area will remain under the influence of the northern jet stream with weak clipper systems propagating through the Canadian Prairie in drier northwest flow aloft. Temperatures will see some subtle day to day variations as 850mb temperatures hover around the freezing mark. This should yield near to slightly above normal temperatures with daytime highs in the 20s to mid 30s and lows in the single digits to teens. Generally these weak clipper systems yield chances for light precipitation. The majority of probabilistic guidance favors these systems to track north of the forecast area through the Canadian Prairie, yielding a mostly dry forecast. Keep in mind that a subtle track shift to the south could mean flurries or light snow accumulations, but this would still only mean minor impacts at best. For Sunday into early the following week, ensemble guidance supports a slight increase in precipitation chances as a stronger upper level trough digs into central North America. This could bring the next appreciable chance for snow accumulations, but there is very low confidence in any details at this time. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 605 PM CST Sun Dec 1 2019 Difficult set of TAFs for the overnight period with stratus evolution uncertain. IFR CIGs and low VSBY has moved in to the DVL area. This area of stratus is expected to slowly move into the GFK and possibly FAR. For TVF and BJI BR or FG is possible overnight as there is a period of lighter winds with clear skies. By tomorrow mid to late morning expecting SW winds 10 to 15 kts and this mixing should improve CIGs and VSBY with VFR conditions expected. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...Dense Fog Advisory until 3 AM CST Monday for NDZ006-007-014-015- 024-026-028-054. MN...None. && $$ UPDATE...JK SHORT TERM...JR LONG TERM...BP AVIATION...JK