486
FXUS63 KFGF 181925
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
225 PM CDT Tue Jun 18 2024

.KEY MESSAGES...

- There is a level 2 out of 5 risk for severe thunderstorms
  between 2 pm and 5 pm. The main hazards will be golfball sized
  hail, 70 mph wind gusts, and a few tornadoes.

- Additional chances for thunderstorms and heavy rain are
  possible late Thursday through early Saturday.

&&

.DISCUSSION...
Issued at 225 PM CDT Tue Jun 18 2024

...Synopsis...
One severe thunderstorm has pulsed up over Hubbard County
Minnesota right now, moving northeast at about 40 mph. There is
a surface low just east of Watertown South Dakota, along the
South Dakota/Minnesota border, with a warm front extending out
to the east-northeast. Based solely on the wind field, this warm
front is now south of an Elbow Lake to Perham to Park Rapids
line. For the rest of the FA, winds have turned to the north
with lower temperatures (mainly upper 50s) and lower dewpoints
(mainly mid 50s). There has been some patchy fog around, but for
the most part it is back above 2 to 3 miles.

...Severe risk through 5 pm...

The severe thunderstorm risk should be fairly short over our
southeast FA, generally ending by 4 to 5 pm, as the surface
front mentioned above continues to push south and east. However,
at 2 pm, there was a sharp thermal gradient from west central
into southwest Minnesota. MLCAPE values ranged from 1000 J/kg
across our southeast FA to over 2500 J/kg over southwest
Minnesota. Decent 850mb winds continued to feed into the area
near this surface boundary, with precipitable water values
around 1.8 inches. For these reasons, SPC has issued a Tornado
Watch that includes Wadena, Hubbard, Becker, Otter Tail, and
Grant counties until 8 pm, but as mentioned, the threat should
end much sooner for this FA.

With the surface low and warm front, there is the potential for
tornadoes. Based off the SPC meso page, the various tornado
parameters are all centered across either southwest Minnesota or
eastward into northwest Wisconsin. Just the fringes of our
southeast Minnesota FA lie on the weaker edge of these
gradients. So far, not seeing much development in the areas to
the south of this FA, possibly due to the warm 700mb
temperatures over them yet. The HREF and other CAMs continue to
support the idea of storms ending in this FA by 4 to 5 pm, as
they progress in the Duluth FA, while other storms develop
south of this FA.

...Thursday through early Saturday...
With a 500mb high sitting over the southeast United States, it
appears the FA will stay in southwest flow. Several waves may
eject out in the Northern Plains, possibly showing a better
potential along the North and South Dakota border into adjacent
areas of west central Minnesota. This area may not have been hit
as hard with the rainfall that ended this morning, but it does
seem that most areas have been wet. Will therefore have to keep
an eye on this system for additional heavy rain and the
potential of added flooding threats.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1248 PM CDT Tue Jun 18 2024

The low clouds and patchy fog are making the aviation forecast
tricky. Although there are still a few sites reporting fog, for
the most part think the fog should be about done. That will not
be the case for the low clouds. Models are holding these over
the area at least through the rest of the day and into tonight.
Think any remaining thunder threat should only affect KBJI for
another couple of hours. Wind should remain from a northerly
direction, with speeds mainly in the 10 to 15 knot range.

&&

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

&&

$$

DISCUSSION...Godon
AVIATION...Godon