080
FXUS63 KFGF 020034
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
734 PM CDT Mon Jul 1 2024

.KEY MESSAGES...

- There is a level 1 out of 5 risk for severe thunderstorms this
  evening for nearly the entire forecast area.

- A system is expected to bring numerous showers and
  thunderstorms to parts of the Northern Plains on Independence
  Day, with a low chance for severe thunderstorms.

&&

.UPDATE...
Issued at 727 PM CDT Mon Jul 1 2024

As of around 7 PM, widespread showers and thunderstorms are
entering into eastern ND from central ND. These showers and
storms will continue northeast through the rest of the afternoon
into evening. Overall, the chance for severe hazards is turning
out to be very low given general lack of better instability and
shear, as well as elevated nature of convection.

There has been a noteworthy amount of lightning, in addition to
heavy rainfall rates. So there is still a chance for storms to
be strong bringing frequent lightning and brief heavy rainfall
potentially causing minor urban flooding.

This convection has displayed progressive forward movement
keeping heavier rainfall rates relatively brief. Latest guidance
continues to show this will be the case through the rest of the
afternoon into evening. This progressive nature of heavy
rainfall will keep chance for flash flooding rather low.
However, cannot discount it completely given earlier day
heavy rainfall priming areas with fully saturated grounds
allowing for efficient runoff. Most sensitive areas are within
the northern and central Red River Valley into northwest
Minnesota, particularly from near Warren/Alvarado to near Thief
River Falls where 2-3 inches have recently fell. An additional
quick 1-2 inches of rainfall is reasonable under heavier
thunderstorms.

While not currently expected, this is where there would be
relatively higher chances for minor flooding from compared to
other areas.

&&

.DISCUSSION...
Issued at 248 PM CDT Mon Jul 1 2024

...Synopsis...
A decent low level jet will remain mainly east of the Red River
late this afternoon and into the evening. This has been the
primary forcing for the showers and thunderstorms across
northwest Minnesota. Precipitable water values have been very
high, around 1.70 inches, and the rainfall rates have been quite
impressive as well. Here at the NWS in Grand Forks, almost an
inch of rain fell in an hour or so. There could be another round
of showers/storms this evening, with another 700mb wave that is
moving into eastern Montana/western North Dakota right now. This
is where the weak surface front is as well. However, there is no
low level jet support out in that area tonight to help sustain
stronger convection too far into the evening. The 500mb low
will be located over southern Manitoba by 18z Tuesday, meaning
there is some support for redeveloping Tuesday afternoon
showers/storms. There should still be somewhat of a break on
Wednesday, before another stronger wave moves in for the July
4th holiday. Beyond that, northwest flow looks pretty well
entrenched, with a few additional waves possible.

...This Evening...
There is a weak surface boundary east of a Williston to
Dickinson line, but there has been extensive cloud cover across
that area most of the day. There has been some developing
convection across the western Dakotas with a little lightning
activity as well. There is ample effective shear out in that
region, but instability has been held down somewhat. As
mentioned in the paragraph above, there is no low level jet
support tonight for anything that does try to move into this FA.
CAMs do still show some sort of line of storms forming from
Minot to Bismarck by late afternoon, potentially moving into our
western FA by 7 pm or so (eastern North Dakota following that).
The HREF shows any UH tracks pretty much ending to the west of
this FA. Therefore think storms may continue to move into our FA
tonight, but on a weakening trend. However, these could still
be efficient rain producers, so will have to watch to see if any
of these move into areas that have seen highers totals up to
now. For the most part, the highest totals have been over the
northern Red River Valley into adjacent areas of northwest
Minnesota.

...Independence Day...
Have been watching this potential for a few days now. If
anything, have seen a slight shift southward with the heavier
precipitation axis in the latest ensembles. Yesterday at this
time, our FA was right in the middle, now it appears eastern
South Dakota into southern Minnesota (where they definitely
don`t need it) are more in the middle. Either way, will have to
keep an eye on this next system over the next few days.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 727 PM CDT Mon Jul 1 2024

MVFR to IFR ceilings are forecast at TAF sites through 10Z.
Additionally, a 2-5 hour period of showers and thunderstorms are
forecast before 08Z as well. Thunderstorms will be capable of
frequent lightning and heavy rainfall. These are the main
hazards that will impact TAF sites through 12Z.

There is a chance for scattered showers and thunderstorms in the
afternoon Tuesday. Decided to leave out of the TAF for now due
to desire to keep TAF length no longer than 6 lines. Will add
this mention in subsequent TAF issuances as chances are medium-
high across the area (although confidence in impacts to any
particular TAF site remains low).

&&

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

&&

$$

UPDATE...CJ
DISCUSSION...Godon
AVIATION...CJ