Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
395 FXUS63 KBIS 230302 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 1002 PM CDT Wed May 22 2024 .KEY MESSAGES... - Scattered to numerous showers are expected tonight across western and central North Dakota. A stray rumble of thunder is possible. - A low pressure system moves into the region Thursday, bringing chances for strong to severe thunderstorms to portions of the area. Gusty winds, large hail, and one or two tornadoes will be possible, particularly for areas along the ND/SD state line. - Periodic showers and thunderstorms are expected over the holiday weekend. - Drier weather and a warm up are in store heading into the middle of next week. && .UPDATE... Issued at 952 PM CDT Wed May 22 2024 Scattered to numerous showers continue their march across the state with the heaviest showers currently located along a line from around Washburn, through far eastern McLean county, up into McHenry county, and then arching over to the northwest through Kenmare and into Burke county. For these areas and east, we did introduce some likely precipitation chances (~70 percent) over the next few hours. Elsewhere, activity will be more scattered through the night with generally low to medium chances of rain (20 to 50 percent). Thunder chances continue to diminish but SPC mesoanalysis does suggest there is still potentially some very weak instability out there. Thus, a stray bolt of lightning or two can`t be ruled out. UPDATE Issued at 635 PM CDT Wed May 22 2024 Widely scattered showers continue to move in/develop across the west. The area with the most widespread showers thus far has been across the northwest and the showers are now starting to move into the north central. Every once in a while we see a lightning strike or two out of the heaviest showers but instability is limited. Current SPC mesoanalysis shows MLCAPE only maxing out around 100 to 250 J/kg and MUCAPE around 500 J/kg. There is some decent effective shear in place a bit further south of the heaviest showers so if more development occurs to the south, there could be a conditional chance for a stronger storm or two through the evening hours. However, this is a low confidence solution for the moment. No major changes were needed for this update. Just blended in the latest observations to the going forecast. && .DISCUSSION... Issued at 408 PM CDT Wed May 22 2024 Visible satellite shows a few clouds moving across the northwestern corner of North Dakota as a surface ridge moves over the center of the state. Winds have slackened west to east over the past few hours as a closed low has lifted to the northeast, over portions of Minnesota, the UP of Michigan, and Canada. Expect light and variable winds to continue for the rest of the afternoon. A few showers and thunderstorms have developed across northern Montana and are starting to move toward the Montana/North Dakota state line. There is a 20-50% chance of a few scattered showers and/or weak thunderstorms expected, particularly for the northwestern and north central part of the state this evening and tonight. At this time, severe storms are not expected. Tonight, a shortwave trough will move from the PACNW to the Bighorns. A low pressure system is expected to develop as the system comes over the Black Hills and West River region of South Dakota Thursday afternoon. A warm front is expected to develop over tomorrow, with still some uncertainty as to where it will set up. Locations range from northern South Dakota to central North Dakota. Instability will increase heading into the afternoon, with the warm front in place. Thunderstorms are expected to develop along the front and within the warm sector, which again brings some uncertainty into which areas may see the best chance for storms and possible severe weather. Any thunderstorms that are able to develop tomorrow in the southeastern part of the area where the warm front will be and a cold front moves through will have the potential of becoming strong to severe. The Storm Prediction Center has placed this area in a Marginal (1/5) to Slight (2/5) Risk for severe storms. The main hazards with any storms will be winds gusting to 60 mph and hail up to ping pong ball size. An isolated tornado or two cannot be entirely ruled out. Overnight, temperatures will fall into the mid-30s in a few locations, bringing a chance of a rain/snow mix to portions of the area. Friday, the low will continue to lift to the northeast, with wrap around moisture expected. Rain chances will continue through the daytime hours and into the evening, eventually ending west to east across the region. Afternoon highs will be slightly warmer than the previous day, at least in the west, climbing into the mid to upper 50s. Heading toward the central part of the state, expect highs in the low to mid-50s. Expect a warm up over the holiday weekend as the are comes under westerly to northwesterly flow. Temperatures will return to the mid to upper 60s for highs and the low to mid-40s for lows. There are some low end chances (20-30%) for showers and thunderstorms Saturday, with a better chance on Sunday (30-50%). The best chances for precipitation will be on Sunday, particularly for the southern half of the state. Memorial Day, a closed low remains in Canada, bringing the possibility for some more wrap around moisture moving into the region. Although chances remain fairly low (20-30%) for showers and storms, this may put a bit of a damper on outdoor holiday or travel plans. An upper ridge moves over the Dakotas heading into mid-week. Dry conditions are expected along with a return of temperatures to the 70s. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 635 PM CDT Wed May 22 2024 A complicated aviation forecast is on tap tonight through Thursday. Isolated to scattered showers will continue to spread across western and central North Dakota this evening and into the overnight hours. The heaviest showers could lead to brief MVFR visibilities and maybe a lightning strike our two. Widespread MVFR ceilings should move into the west and north Thursday morning (impacting KXWA/KDIK/KMOT) and spread into the central by the early afternoon (impacting KBIS). Some of the higher resolution models are suggesting some ceilings dipping into IFR categories but confidence is too low this far out to include mention in any site specific forecast at this time. More showers and thunderstorms will develop Thursday afternoon across the southwest and into the central. A few of these storms across the south could become strong to severe. If one of the strongest storms move overhead, they could produce hail to the size of ping pong balls and winds to 60 mph. A tornado or two is possible as well. Winds may become gusty and erratic in and around any showers or thunderstorms. KJMS may remain in VFR categories through the period, but they should at least see low VFR ceilings in the afternoon. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...ZH DISCUSSION...Hollan AVIATION...ZH