Mayville, North Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

359
FXUS63 KFGF 150341
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1041 PM CDT Thu Aug 14 2025

.KEY MESSAGES...

- There is a 2 of 5 risk for severe thunderstorms late this
  afternoon and evening. Hazards could include large hail up to
  the size of tennis balls, damaging wind gusts up to 70mph, and
  isolated tornadoes.

- There is a level 1 out of 5 risk for severe thunderstorms Friday
  afternoon within southeast North Dakota into west- central
  Minnesota.

&&

UPDATE
Issued at 949 PM CDT Thu Aug 14 2025

A few discrete thunderstorms have been noted over the last 2
hours with one currently in western/northwest Polk county at
945pm. A few other attempts to the northwest of Fargo have been
struggling to overcome capping though remain in an environment
supportive of at least quarter size hail if they can overcome
it. Overall MLCAPE > 3000j/kg and eff shear ~30kt will continue
to support large hail over 2" in the strongest updrafts and the
potential for a tornado or 2 through 11pm before diurnal cooling
forces parcels to no longer be sfc based. Storms should then
either dissipate of congeal into a line as shortwave forcing
arrives from the NW with predominant wind threat after 12am.

UPDATE
Issued at 620 PM CDT Thu Aug 14 2025

While storms are still expected for at least portions of
northwest Minnesota this evening, storms elsewhere are less
certain and initiation before 9pm in our area is optimistic at
best. CAMS still seem to favor a more cluster/liner moder
overall with a brief window for discrete storms which could
produce hail upwards of 2". Storm timing looks to be 9pm onwards
with back building storms along and south of I94/HWY10 through
the later part of the night.

&&

.DISCUSSION...
Issued at 1257 PM CDT Thu Aug 14 2025

...Synopsis...

The upper air flow pattern will be characterized by zonal flow
for the first few days of the period, transitioning it large
scale ridging by the end of the weekend. This will allow for
periodic chances for showers and thunderstorms through the
weekend, with the greatest risk this afternoon, particularly for
severe thunderstorms.

Signals for late next week show at least some breakdown of the
upper ridge which would bring the chance for additional showers
and thunderstorms, some potentially strong to severe. Time of
year and distance from the predictability horizon precludes any
potential details at this time.

...SEVERE STORMS TODAY...

Surface analysis at 18z indicates a surface low over central
Manitoba with a pressure trough stretching down through the
Devils Lake and James River basins. A tight theta-e gradient
sits behind the trough, which is likely going to be the focal
point for showers and thunderstorms this afternoon.

Capping is likely to limit convective potential, but soundings
right now from the RAP13 indicate a loaded gun with an
absolutely unstable elevated mixed layer. It seems likely that
at least some convection is going to form this afternoon, the
main question is what is the scope.

Should storms form, they will likely become supercells capable
of significant hail exceeding two inches. Straight hodographs
aloft also favor some potential splitting storms which could
inhibit hail production pushing towards higher bounds, but that
will depend on the scope of convective coverage. With the very
high DCAPE, severe wind is possible with any RFD punches.
Tornado potential should be heavily mitigated by low wet bulb
temperatures and high DCAPE. Having said that, surface vorticity
does exist so tornadoes cannot be ruled out. Storms should
diminish after sunset for the most part thanks to the strongest
forcing being near the surface, however the existence of a
residual EML could potentially create brief additional
convection overnight. The probability for this is low as the
low-level jet is displaced to the east, but it cannot be ruled
out for some elevated hail potential overnight from a cold front
aloft that provides just enough nudge.

...SEVERE STORMS TOMORROW...

As the front sags southward overnight, dewpoints will continue
to linger behind the front, around the 60s and 70s. This means
instability will stick around in the southern half of our CWA,
however forcing is very limited so confidence is low on
potential convection tomorrow afternoon. If thunderstorms form,
the general threat at this time should be 60-70 mph winds with
1.5 inch hail. Shear is much more limited as the main jet will
constrain to Canada.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1041 PM CDT Thu Aug 14 2025

VFR conditions through the night with a few thunderstorms
tracking east through northwest Minnesota. TVF and BJI will see
the main impacts from these storms with FAR and GFK likely to be
spared at this point. TVF will be clear of storms by 07z with
BJI seeing impacts as late as 10z. No other aviation impacts to
be concerned about.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.

&&

$$

UPDATE...TT
DISCUSSION...Perroux
AVIATION...TT