![National Oceanic and Atmospheric Administration](/build/images/header/noaa.d87e0251.png)
![National Weather Service](/build/images/header/nws.4e6585d8.png)
![United States Department of Commerce](/build/images/header/doc.b38ba91a.png)
Area Forecast Discussion
Issued by NWS Grand Forks, ND
Issued by NWS Grand Forks, 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
634 FXUS63 KFGF 141521 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 1021 AM CDT Wed Aug 14 2024 .KEY MESSAGES... -Showers and thunderstorms will increase in coverage today and last into Thursday. Heavy rain and lightning are the main impacts. && .UPDATE... Issued at 1021 AM CDT Wed Aug 14 2024 A cluster of showers/embedded thunderstorms have spread into far southeast ND with isolated showers now along the Highway 2 corridor. More organized synoptic ascent doesn`t arrive until later this evening/overnight, so we are in a pattern with increasing deep moisture and smaller scale features leading to harder to predict evolution/coverage within our forecast area. Higher coverage is tending to be concentrated near several boundaries(more obvious in wind/theta-e fields) near our south and west of our CWA. At least for now HRRR (being a hot-start CAM) is reflecting near term trends, but beyond the morning I don`t have as much confidence in coverage/evolution. For now I`ve made adjustments to better reflect near term trends, and held off on any major adjustments beyond midday (blended previous forecast). Impacts in our area through midday are mainly moderate rain and isolated lightning activity. As the deeper moisture plume overspreads our area along with more organized ascent the threat for heavy rain increases, though HREF PMM doesn`t show values that raise concerns for our hydrological forecast area unless the higher end values fell in a short enough period of time over one of our towns/urban areas where there is poor drainage conditions lowering confidence in more than localized/minor impacts. Considering that, a watch is not being considered at this time. UPDATE Issued at 643 AM CDT Wed Aug 14 2024 Still many different scenarios for today rainfall evolution. There are some t-storms forming in central ND from Minot toward Dickinson and they are moving north-northeast. Movement of this activity this morning would keep majority of the activity west of Devils Lake unlike what 00z HREF had and what QPF is based on 12z-18z. Meanwhile something new is in the picture which is an area of showers moving north thru NE SD and this looks like will enter SE ND. This feature is more like what the 00z/06z High Resolution Canadian has but this model intensifies it over Jamestown today and has very little precip DVL region. So still no clearer in what path todays rainfall will take. Hence why we have pops in most areas thru today. && .DISCUSSION... Issued at 351 AM CDT Wed Aug 14 2024 ...Synopsis... 500 mb low moving slowly east/northeast thru west central/central Saskatchewan with one area of concentrated t-storms in that area. In our region though a second weaker upper low is over parts of Oregon/Idaho with a broad 500 mb ridge into Minnesota. This puts our area in southwest flow aloft and within this flow there are numerous short waves seen on water vapor this early morning. How these short waves move and bring development of showers/t-storms is the main forecast challenge. PWATS are near 2 inches in a zone over central SD/ND and this ribbon of deeper moisture slides slowly east today but basically remains in the Devils Lake-Jamestown-Bismarck region thru this evening. Thunderstorm/heavy rainfall situation today remains typically uncertain. HREF and various CAM guidance highlight what is the most likely scenario which is t-storms from NW SD or SE MT moving northeast and developing within this deeper moisture area toward Devils Lake during the course of the day. Latest HRRR backs off on timing and focuses it more into DVL region midday vs WPC/HREF had higher precipitation 12z-18z today. At this point and time, either scenario is just as likely. Not much development in central ND at 08z but as short wave from NW SD/NE MT moves northeast rapid development of t-storms may occur and bring the heavier rainfall this morning or wave is slower to move and slower to develop t-storms and main rain is midday or afternoon into Devils Lake area. Either way...idea is for the concentrated area of showers and t-storms in central ND into Devils Lake area to advance east in time into the Red River valley late today/this evening and into NW MN tonight...though with lower intensity rainfall. With high PWATS localized rain amounts 2-3+ inches are possible in the zone thru central ND into Devils Lake basin. Uncertainty is high enough though and also past 7 day NDAWN precipitation for the area shows little to no precipitation for most of the Devils Lake area. Thus feel going with a flood watch before storms form is not quite the way to go due to prior conditions have been mainly dry weather. Thursday will see 500 mb trough to our west slide over eastern Dakotas/Minnesota with Global Canadian and ECMWF developing a closed low aloft vs GFS is more progressive. 00z ECMWF remains more consistent from run to run and at this time favored in developing area of rain around the upper low into parts of E ND/RRV and much of northwest MN Thursday on backside of the upper low. Not a heavy rainfall but a general rain area. If more progressive GFS is right then rain area Thursday is less and ends as system moves east. Weekend into early next week shows an upper level ridge building into south central Canada and northern Plains. 00z operational GFS is a complete outlier compared to the 00z GFS ensemble and discounted at this time. It has an upper low in NW Ontario into Manitoba vs a ridge. Net weather result with a ridge would be temps more into the low 80s. Some risk of a shower/t-storm early and mid next week due to short waves moving. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 643 AM CDT Wed Aug 14 2024 Kept forecast idea from models in that MVFR cigs will develop in an increasingly moist low level environment later today and tonight. Ceilings in all areas dropping into the sub 2000 ft range with risk of IFR (sub 1000 ft ceilings) in some areas, such as KBJI, which climatologically speaking favors lower ceilings in this south-southeast wind environment than other areas. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Riddle/DJR DISCUSSION...Riddle AVIATION...Riddle