-- Discussion containing changed information from previous version are highlighted. --
247
FXUS63 KFGF 161447
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
947 AM CDT Sun Jun 16 2024

.KEY MESSAGES...

- Isolated severe thunderstorms are possible in the southern
  Red River Valley and west-central Minnesota this evening and
  overnight. Quarter sized hail and 60 mph wind gusts are
  possible; however, heavy rain and flash flooding could cause
  more substantial impacts late Sunday night through Tuesday.

- Isolated to scattered severe thunderstorms are possible
  Monday evening and overnight into Tuesday morning. Large hail
  and torrential rainfall will be the primary threats; however,
  isolated damaging wind gusts to 60 mph are possible.

&&

.UPDATE...
-- Changed Discussion --
Issued at 947 AM CDT Sun Jun 16 2024

Most of the early morning convection has moved into our far
eastern counties or out of the forecast area. However, some
cumulus starting to build in west central MN ahead of the trough
axis where there is still plenty of MU CAPE, so not out of the
woods yet as far as convection goes. CAMs not very helpful this
morning. Made some tweaks to POPs but will have to make some
additional adjustments as the day goes on and things develop.

UPDATE
Issued at 631 AM CDT Sun Jun 16 2024

Strong thunderstorms continue to work east this morning, with
the strongest activity now crossing into Minnesota. Winds have
been sporadic, with reports generally in the range of 35 to 50
mph during the strongest storms. Made few adjustments to timing
this update, as well as added the Devils Lake Basin to a Wind
Advisory for this afternoon as we could see gusts upwards of 40
mph.
-- End Changed Discussion --

&&

.DISCUSSION...
Issued at 413 AM CDT Sun Jun 16 2024

...Synopsis...

Active weather prevails through much of the forecast period as
southwest flow dominates the H5 pattern across the Northern Plains
and Upper Midwest through the middle of next week. Moisture flow
into the region streams along an 850 to 700 mb jet with a source
region in southeast Texas. As such, PW values are expected to climb
into the 90th to 98th percentile across the forecast area today
through Tuesday ahead of an approaching theta-e gradient boundary.
H5 ridging over the Atlantic Coastal Plain will keep the overall
flow pattern moving very slowly, thus causing continued exposure to
southwest flow across the central and northern CONUS.


...Isolated Severe Thunderstorms Today...

Remnant strong storms will continue to weaken this morning along a
line moving from west to east, mainly north of Highway 2. Additional
storms could form along this line later this morning or early
afternoon in the northern Red River Valley and northwest and west-
central Minnesota, bringing another chance for large hail and
isolated gusty winds. MUCAPE will climb into the 1500 to 2200 J/Kg
range, with 0-3Km shear up to 25 knots. Deep layer shear will
generally be around 40 knots. Hail up to the size of quarters will
be the primary threat. Most of this thunderstorm activity looks to
be east of the area by mid-afternoon as the theta-e gradient
boundary moves into central Minnesota by around 03Z.


...Scattered Severe T-Storms and Flash Flooding Mon and Tue...

Heading into Monday, another shortwave rides northeastward along
southwest H5 flow into the Northern Plains. Antecedent moisture
remains draped across the area with PW values well over the 90th
percentile. Storm development is expected during the evening hours
and into the overnight period into Tuesday morning. Looking at CAPE
and MUCAPE, the main concern will be elevated hail producing severe
thunderstorms and torrential rainfall. Isolated damaging wind gusts
are possible; however, this threat will likely occur very early
during the developmental stage of the strongest storms. Mean storm
motion along the boundary will support the training of storms along
the same area over a long period of time, perhaps several hours. As
such, flash flooding is a concern through much of the overnight
hours and into Tuesday morning.

Heavy rain continues eastward through the day Tuesday, with most
activity leaving the forecast area by mid afternoon.


...Active Pattern Continues with More Rain Possible...

Another trough traverses the flow heading into late next week. Early
indications allow for the mention of additional moderate to heavy
rain late Thursday through Friday. Details will become more clear as
we get closer, but pattern support remains somewhat strong for
impactful weather late next week.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 631 AM CDT Sun Jun 16 2024

Primary impacts to aviation this morning will be thunderstorms
moving from west to east across the area. KGFK and KFAR will see
TSRA through around 13Z before becoming -SH with VCTS through
about 14Z. KTVF will see similar conditions. Look for VFR to
MVFR conditions outside of thunderstorm activity, with IFR to
LIFR CIGs and visibility during stronger thunderstorms. Much of
this activity will push east through the morning before moving
out of the area during the afternoon. KBJI is seeing low
ceilings this morning and could have a period of showers and
thunderstorms this afternoon; however, confidence in timing is
low at this time as guidance has a large degree of variability.
In either case, most of the area should see VFR conditions as we
approach 00Z.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
ND...Wind Advisory until 7 PM CDT this evening for NDZ006-007-014-
     015.
MN...None.
-- End Changed Discussion --

&&

$$

UPDATE...Lynch/JR
DISCUSSION...Lynch
AVIATION...Lynch