794
FXUS63 KFGF 160913
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
413 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.

&&

.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 /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1140 PM CDT Sat Jun 15 2024

Low level clouds are moving into the Red River Valley and
through BJI this evening. MVFR conditions persist for GFK, FAR,
and TVF this evening through 12-14z. BJI is experiencing IFR
conditions and we are expecting improvements around 15-17z.
Thunderstorms will be moving into the DVL area overnight around
08-12z, with frequent lightning and potential for erratic wind
changes. Conditions are expected to clear out by 12-15z, with
winds turning from the south toward the west. DVL, GFK, FAR, and
TVF will see higher wind potential in the late morning through
early afternoon hours. Gusts up to 30kts will be possible in DVL
tomorrow afternoon and up to 25kts for TVF, FAR, and GFK.
Secondary system moves in end of the TAF period, with a BKN
cloud deck and further precipitation chances post TAF period.

&&

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

&&

$$

DISCUSSION...Lynch
AVIATION...Spender