FXUS63 KFGF 070442 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 1142 PM CDT Mon May 6 2024 .KEY MESSAGES... - Strong southeast winds will continue this afternoon into tonight across eastern North Dakota and adjacent portions of Minnesota, with gusts up to 50 mph at times. - Showers and isolated thunderstorms will affect the region through Wednesday. && .UPDATE... Issued at 1142 PM CDT Mon May 6 2024 Starting to see more coverage of showers and isolated storms within the Red River Valley. This is connected to a long line of showers/storms extending all the way down into the Central Plains, which is generally expected to lift northward overnight. The CAMs are indicating most of this activity moving into the highway 200 corridor and northward by Tuesday morning. So far, NDAWN stations are indicating a fair coverage of 0.10 to 0.50 inches of rain along and west of the Red River Valley. As this line of showers/storms continues to lift northward, these amounts may be more on the lower end of that range (more so 0.10 to 0.25 inches). UPDATE Issued at 947 PM CDT Mon May 6 2024 Wind speeds quickly dropped off at quite a few sites right around 9 pm, so was able to cancel most of the Wind Advisory a little early. Still have seen a few higher gusts in the Gwinner to Valley City corridor, so kept the advisory going yet there. Did see the latest observation at Gwinner really dropped now too, so may be able to cancel the last 3 counties a little early too. However, will wait for another round of top of the hour observations before doing so. UPDATE Issued at 620 PM CDT Mon May 6 2024 No huge changes with this forecast update. Will slow down the arrival of likely precipitation chances for another few hours. Seems like there is more areal coverage of showers/storms organizing over eastern South Dakota now, but if they hold together as is, it will be a few more hours until they arrive in the southern FA. There is some lightning activity over southeast North Dakota, but nothing too concentrated or long lasting. As the previous shift noted, 850mb winds crank up to around 60 knots around or after sundown (and continue through most of the night), so the echoes on radar are moving very fast. && .DISCUSSION... Issued at 212 PM CDT Mon May 6 2024 ...Synopsis... A strong upper level trough is moving out of the Rockies into the central and northern High Plains as seen on water vapor satellite imagery. This is helping rapid deepening of a surface low in the western Dakotas, generating an expansive increased wind field as well as drawing in moisture and lift into the region. By Tuesday afternoon, the upper trough closes into an upper low, becoming stacked on top of surface low halting its deepening/strengthening. This also allows the low to stall over the Dakotas by Tuesday. A second upper trough moving through the Intermountain West Wednesday will then help the upper low move southeast out of the Dakotas by Wednesday night. Northwest flow aloft then develops with the help of upper ridging over the West around Friday, with ensemble guidance all depicting an open, progressive shortwave trough moving out of central Canada into the Upper Midwest. While there is strong consensus in this synoptic wave, there are differing scenarios in its progression and strength. Uncertainty in the upper pattern then degrades after Friday's shortwave passage with either upper ridging out of the West becoming the dominate influencing mechanism for our weather, or upper troughing over the Great Lakes. Both would still favor average temperatures for our area, however. ...Strong winds today and tonight... Strong surface pressure gradient over our area and mixing of low level winds in the 40-50 kt range is contributing to sustained winds 25-35 mph with gusts up to 50 mph in eastern North Dakota into portions of adjacent northwest and west-central Minnesota. Southeasterly direction of winds is favoring strongest winds in the southern Valley with the help of downsloping within the southern Valley, as well as locally better mixing from daytime clearing. This will continue advisory-criteria winds through the afternoon into the evening. After sunset, daytime heating ceases, although the pressure gradient remains tightened over our area, along with some continued mixing with the help of either downsloping/terrain influences as well as transferred winds from aloft with the help of convection/weak thunderstorms tonight. Still thinking winds will remain near or at advisory-criteria after sunset until around midnight. Winds aloft increase over 50 kt tonight, which introduces some uncertainty in tapping into these near warning- type criteria. However, the chance in seeing warning-criteria winds is low, at around 10% between 7pm - 1am. ...Showers and thunderstorms through Wednesday... Lift and strong moisture transport into our area gives high confidence in widespread showers into eastern ND and west- central and northwest MN. Weak instability feeding into this moisture transport allows the chance for weak thunderstorms tonight into Tuesday. Tuesday midday, some high resolution guidance does bring a surface front through into our area, coupled with relatively warmer/more moist air mass. With forcing aloft and at the surface from convergence and frontal lift amid surface CAPE values 100-500 J/kg, clusters of semi-discrete and/or a line of thunderstorms are expected. In this same area, low level winds veer with height, with good ventilation aloft. Should thunderstorms remain semi-discrete and attach themselves on the boundary, funnels and/or a couple of quick tornadoes cannot be ruled out. This conditional chance is low, less than 10%, but still exists and would increase if more discrete mode and/or greater instability becomes more favored. The window of opportunity for such potential exists between 11am to 4pm. Otherwise, accumulated precipitation is forecast to range in the 0.20 - 0.75 inches, with locally higher amounts up to 1.5 inches in areas that see numerous rounds of showers and thunderstorms. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 1142 PM CDT Mon May 6 2024 Kept with the same ideas from the 00z set of TAFs. Still trying not to chase the showers/storms with too many TEMPO groups. Showery activity tends to have on and off periods, but think for at least most of the first 6 hours of the TAF period there will be more "on" periods. Therefore, will just mention -SHRA in the predominant group and leave the TEMPO's off. There has been some lightning, but overall think that will stay isolated enough that will leave that mention out too. Put the LLWS in the TAFs with the 00z issuance, and will keep that through most of the night as well. Wind speeds have been very challenging, as some stations are still seeing breezy winds, while others have lost their gusts. Think those that have lost gusts will get them back again, and that is really not worth chasing too much either. Beyond that, have gone with VFR conditions arriving again by mid to late Tuesday morning, but don't have much confidence that it will scatter out. If it does scatter out, some instability could form again south of the highway 2 corridor, leading to isolated shower/storm development again. The breezy conditions will return by mid Tuesday morning, before they decrease again by late afternoon and early evening (although much less than today). && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Godon DISCUSSION...CJ AVIATION...Godon