Area Forecast Discussion
Issued by NWS Grand Forks, ND
Issued by NWS Grand Forks, ND
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800 FXUS63 KFGF 141930 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 230 PM CDT Tue May 14 2024 .KEY MESSAGES... - On and off showers through at least the next week. - Thunderstorm chances increasing over the next few days. A low probability scenario exists which would include a few strong thunderstorms on Friday. && .DISCUSSION... Issued at 230 PM CDT Tue May 14 2024 ...Synopsis... Water vapor imagery indicates zonal flow aloft with several upstream shortwaves meandering toward the region. Ensemble guidance in good agreement with the general zonal flow pattern, but differ with timing, strength, and location of individual shortwaves. All in all anticipate on and off showers through at least the next week with possibly a stronger thunderstorm. Through the next week, the 25-75 percentile range for rainfall amounts across the majority of the forecast area is 0.50-1.50 inches. ...On and Off Showers... Water vapor indicates immediate subsidence through the late afternoon behind the departing wave, but many more waves approaching. HRRR indicates a few storms initiating across north central ND this afternoon moving into the Devils Lake basin this evening. This scenario seems plausible given the current plume of instabilty ahead of the surface convergence/low pressure. Any storms that do develop would quickly dissipate this evening as they depart from the instability. Next wave of concern is currently across Idaho, with another lead wave across southwest South Dakota. Ensemble guidance in good agreement indicating these features will slowly propagate through the region on Wednesday, with rain chance increasing especially Wednesday afternoon and into the evening. Beyond Wednesday, timing and location of waves uncertain. ...Severe Storm Potential... There is a stronger wave that will be approaching from the northwest by Friday, and ensemble guidance shows many different scenarios with how this system will develop across southern Canada. Location of this feature by Friday into Saturday will be important, as stronger and further west would lead to increased moisture return along with warmer temperatures and greater instability, with the potential for strong to severe storms. In fact, the CU machine learning indicates a low chance for severe storms Friday and Saturday. Of course, a weaker and further east system would not allow for moisture return or warmer temperatures thus limiting instabilty. At this point each scenario has an equal chance of happening. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1236 PM CDT Tue May 14 2024 VFR for all sites this afternoon and tonight. Isolated showers will be here and there but no impacts to vsby or ceilings. Although probability is too low to include within the TAF, will need to watch if thunder can affect KDVL this evening. Otherwise, MVFR cigs are expected to affect most TAF sites on Wednesday, although timing uncertain. Most confidence these lower cigs will move into KDVL by Wednesday morning. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ DISCUSSION...TG AVIATION...TG