Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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598 FXUS63 KBIS 040832 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 332 AM CDT Thu Jul 4 2024 .KEY MESSAGES... - Numerous showers and scattered thunderstorms are expected today, especially during the afternoon. However, the entire day will not be a washout, as much of the activity will be of the "hit or miss" variety. - Slightly below normal temperatures with daily chances for showers and thunderstorms will continue through the holiday weekend. Highs will mainly be in the mid to upper 70s. - A gradual warming and drying trend is expected to begin next week. && .DISCUSSION... Issued at 331 AM CDT Thu Jul 4 2024 At the moment, surface low pressure is positioned across northern North Dakota, while a trough aloft continues to deepen and pass across the Dakotas. Showers and isolated thunderstorms have already begun to develop across the southern half of the area this morning, with additional showers slowly making their way south from southern Manitoba and southern Saskatchewan. Lightning activity has been limited due to the near complete lack of instability, but a few isolated lightning strikes have been reported to the north of Bismarck. Mid- to high-level clouds have expanded across nearly the entire area, and will remain across the area through the day today. Lows this morning will mostly be in the lower to mid 50s, with light and variable winds. Confidence remains fairly consistent with regards to the forecast for Independence Day. As the aforementioned trough and attendant surface low slowly move east through the day, wraparound moisture will help with the formation with numerous showers and isolated to scattered thunderstorms across all of western and central North Dakota. These chances will be maximized from the early afternoon through the evening, before beginning to decrease towards/after sunset. The important thing to know with the setup for today is that while chances for showers will be pretty high (roughly looking at 60 to 70% chances across essentially the entire area), the spotty nature of these showers will make for a very "hit or miss" day when it comes to storm activity. There`s a good chance that any of these numerous storms will impact any given location, but the storm itself will be rather short lived, allowing for breaks between rounds of rain. Basically, the day today will not be a washout, but there`s a pretty good chance that most locations will see a quick round of rain at some point during the afternoon and evening hours. Luckily, given the persistent cloud coverage, lack of instability and shear, and the weak forcing at the surface, severe weather will not be a concern today. Given the influence of the trough aloft, high temperatures will be relatively cool, with most areas staying in the low to mid 70s. Under the slack pressure gradient, winds will generally be light, with a few areas in the far southwest potentially seeing speeds up to 15 mph. Beyond the holiday today, we can expect near daily chances for showers and thunderstorms through the weekend. Cyclonic northwesterly flow aloft will allow for a few additional shortwaves to pass across the Dakotas, bringing about these chances for showers and thunderstorms. These chances are maximized every afternoon and evening, with the highest chances in the northwest on Friday, the north-central on Saturday, and in the northeast on Sunday. While severe weather remains unlikely with these waves of precipitation, the CSU machine learning guidance has picked up on a narrow corridor of low severe hail chances across the James River Valley on Sunday. At the moment, the shortwave passing through the area on Sunday does appear to be the most robust out of any of the waves through the weekend, but the forcing and instability still appear to be marginal at best. We will continue to monitor this period for any severe potential over the coming days. Generally, with the pattern persisting through the weekend, we can expect highs each day to be mostly in the 70s, with overnight lows mostly in the 50s. Winds will generally be light and out of the northwest, with sustained speeds maxing out around 10 to 15 mph. Heading into next week, confidence has continued to increase in a breakdown of the cyclonic pattern aloft, resulting in a slow warming and drying trend through the week. The large ridge currently in place across the western CONUS is forecast to very slowly build eastward through the coming days, with the 850 mb thermal ridge expected to begin influencing North Dakota on Monday. Chances for rain decrease thereafter, with clearer skies and drier conditions expected under the ridge. NBM spreads in high temperatures have narrowed considerably through Wednesday, with the 25th/75th spread only reaching 5 to 6 degrees during this period. Even though the spread increases heading into the end of next week, the general warming trend actually continues even further. We`ll have to continue monitoring the extended period to see the extent of this warming trend, but as it stands right now, we may start seeing widespread highs in the 80s by Thursday, with temperatures increasing further beyond that point. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 1223 AM CDT Thu Jul 4 2024 Showers and thunderstorms will remain possible overnight, with the highest chances near KBIS. Through the day today, frequent showers and thunderstorms can be expected across the entire area and at every terminal. However, given the spotty nature of these showers, it will be hard to tell exactly when any given location will see rain. In any storm that develops, gusty winds and IFR visibilities may be possible. Otherwise, mostly VFR to occasionally MVFR ceilings are expected through the TAF period. Winds will be 5 to 10 kts, generally out of the northwest. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Besson AVIATION...Besson