Area Forecast Discussion
Issued by NWS Grand Forks, ND
Issued by NWS Grand Forks, ND
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186 FXUS63 KFGF 260308 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 1008 PM CDT Wed Sep 25 2024 .KEY MESSAGES... - Near critical fire weather is expected Thursday across southeastern North Dakota. There is a 20% that critical fire weather conditions develop. && .UPDATE... Issued at 1000 PM CDT Wed Sep 25 2024 Quiet weather persists. Clear skies continue, dewpoints are dry enough such that the probability of fog is low, and wind speeds remain below 10 mph. No weather impacts are expected overnight. UPDATE Issued at 643 PM CDT Wed Sep 25 2024 Clear skies and limited wind will continue through the overnight hours. No weather impacts are anticipated overnight tonight. && .DISCUSSION... Issued at 223 PM CDT Wed Sep 25 2024 ...Synopsis... Quiet weather will continue through the evening and overnight hours due to upper level ridging. While ridging remains the main story through the weekend, there is a shortwave that will pass through on Thursday. As the ridge breaks down early next week, a trough propagates eastward, bringing with it cooler temperatures and very low chances for a few showers. ...Wind and Fire Weather Thursday... As the shortwave progresses eastward, its associated tightening pressure gradient in conjunction with a 40 knot 850 mb jet will promote gusty southerly winds. The area of highest wind looks to be confined to the Devils Lake Basin and far northern Red River Valley. In these areas, there is a 70% chance of seeing wind gusts of 40 mph or higher. Further south, winds are expected to be lighter, as winds aloft will not be as strong due to the more northern placement of the jet. While winds will be lower across the south, they are still anticipated to be breezy, with gusts up to 30 mph. RH values as low as 25% raise concerns for near critical fire weather. The largest limiting factor for critical fire weather is that the driest fuels and lowest RH values are across southeastern ND, while the highest forecasted winds are displaced to the north. Therefore, while critical fire with is not anticipated, there is a 20% chance that they do develop. This is most favored where the driest fuels and RH values can overlap with the higher winds, as the HREF shows when using dual probabilities for RH and sustained winds. ...Weekend and Beyond... Behind the passing shortwave, ridging will continue through Sunday with well above average temperatures. A trough coming off of the Pacific Sunday night into Monday will bring high temperatures down to their seasonal averages, which are in the 50s and 60s. Another period of breezy winds, this time out of the northwest, is anticipated behind the cold front. While the trough will bring enough forcing to provide some showers Monday and Tuesday, the placement and coverage of these are unknown. Therefore, POPs remain under 20% early next week, painting the idea of scattered showers. One other thing to note, breezy winds overnight should at least limit the frost risk. No clear signal exists for widespread frost early next week behind the cold front, but widespread low temperatures on either side of 40 degrees seems likely Tuesday and Wednesday mornings. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 1000 PM CDT Wed Sep 25 2024 Low level wind shear and wind gusts will continue to be the only aviation impacts for the TAF period. Wind shear will continue through 12z at DVL and possibly GFK. Winds will increase after 12z, gusting as high as 30-35 knots at all TAF sites except BJI. Winds will diminish after 00z but remain above 12 knots for all TAF sites. The wind direction will also slowly shift to 290-310 after 03z, with only DVL making it to its final wind direction by the end of the TAF period. Winds will shift at all other TAF sites after 06z. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...CJ/Perroux DISCUSSION...Rafferty AVIATION...Perroux