700 FXUS63 KFGF 221935 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 235 PM CDT Sun May 22 2022 .SHORT TERM...(This evening through Monday night) Issued at 235 PM CDT Sun May 22 2022 One more chilly night is expected across the FA tonight, with frost possible in some areas east of the Red River Valley. This will be the main forecast impact in the short term. 500mb cyclonic flow and cold 500mb temperatures brought another cloudy afternoon with showers/sprinkles. These should fade away this evening, with winds also becoming fairly light (especially east of the Valley). This should bring a threat of frost east of the Valley, with lows of 33 to 36 degrees. Other areas further west should be a tad warmer, and south winds holding in the 10 mph range should also help. 500mb temperatures on Monday afternoon look similar to today, while 850mb temperatures warm several degrees. Another short wave should move into mainly western portions of the FA by afternoon/early evening. This looks to set up one more day of afternoon/early evening showers, maybe even a clap of thunder. This activity should fade away during the later evening. Lows Monday night should be in the 40s, so no more frost threat. .LONG TERM...(Tuesday through Sunday) Issued at 235 PM CDT Sun May 22 2022 Overview... An overall quiet long term is anticipated, with the greatest chance for precipitation returning to the region by early next weekend. There may also be a chance for some light rain on Wednesday as well, but there is low confidence in rainfall coverage due to high ensemble variability. Otherwise, temperatures will be on the upward swing toward near normal values by the end of the week. Discussion... An upper level trough is expected to dig in over the central Plains during the midweek period. As this occurs, an upper ridge will look to build in over the southeastern CONUS. This will set up a tricky midweek forecast as the trajectory of the trough will be dictated by the strength of the ridge. A stronger ridge would push the advancing trough further westward, bringing precipitation impacts to a wider swath of the CWA, while the inverse would lead to some light rain across eastern portions of the CWA. Latest NBM guidance at this time favors the latter scenario, giving a 15-25% chance for rainfall to exceed 0.25" across portions of northwestern and west central Minnesota. There are, however, ensemble suites, particularly the GEFS, that favor the former scenario. This is further evidenced within cluster analysis QPF trends indicating a roughly 40% chance of more widespread rainfall and a 60% chance of less widespread rainfall. Suffice to say, despite the potential for increasing rain chances, we look to be on the northwestern periphery of the overall system, and should only see light accumulations of generally less than 0.5", with the main questions centering around the coverage of potential rainfall. Moving into the remainder of the week, we should begin to see pressure rises at the surface and upper level ridging building into the Plains following the midweek system. These factors combined look to yield widespread subsidence aloft with temperatures warming into the upper 60s to 70s across much of the forecast area on Thursday and Friday. Attention then turns to the developing weekend system. Cluster analysis is in good agreement and is quick to rid the Plains of the upper level ridging as an upper trough begins to dig in over the western CONUS. This will work to induce southwesterly flow over the northern Plains once again, which will in turn yield increasing precipitation chances as well. The first embedded shortwave looks progged to impact the region on Saturday. Confidence is still low on the exact impacts likely from this system but latest NBM guidance does paint 30-45% probabilities of 24-hour QPF exceeding 0.25" across much of the CWA. With the general trajectory of this system, there will also be the possibility for some thunderstorms to be involved, although to what degree is still very uncertain. As a result, will continue to monitor latest forecast trends with this system moving ahead. && .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) Issued at 1225 PM CDT Sun May 22 2022 Mainly BKN cumulus will affect the TAF sites through the early evening, before clouds decrease again. There could be a sprinkle or light shower this afternoon, but it would be so minimal that they will not be mentioned. Some sort of westerly wind will continue through the afternoon, before winds become light in the evening and overnight. These winds will pick up again from the SSW on Monday morning. && .HYDROLOGY... Issued at 235 PM CDT Sun May 22 2022 Many locations along the Red and Sheyenne rivers remain in at least minor flooding, although all water levels are either steady or are currently declining or expected to decline. Some moderate to major flooding is still ongoing, mainly along the northern mainstem Red River as well as the lower Sheyenne River. While chances for precipitation are in the forecast, amounts are expected to remain generally under a quarter of an inch before Thursday. Light amounts of this caliber are not expected to cause any additional, significant rises to rivers. With a lack of substantial precipitation, high water levels will continue to recede through much of the week. There is a chance for more widespread precipitation later next week after Friday, including the chance for thunderstorms. Widespread amounts of half an inch or more remain a possibility (20-40% chance of occurrence) with this late week rainfall. It remains unclear how this may impact rivers, but at this time we are not expected additional significant crests to rivers given the opportunity to recede through the majority of the week. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...Frost Advisory from 2 AM to 8 AM CDT Monday for MNZ006-008-009- 013>017-022>024-028-032. $$ SHORT TERM...Godon LONG TERM...Rick AVIATION...Godon HYDROLOGY...CJ