184
FXUS63 KFGF 121537
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1037 AM CDT Fri Jul 12 2024

.KEY MESSAGES...

- Heat related impacts are expected into this weekend,
  especially Saturday afternoon. Impacts will be highest for
  heat sensitive or vulnerable groups and anyone without
  effective cooling or hydration.

- There is a level 1 out of 5 risk for severe thunderstorms tonight
  for eastern North Dakota into far northwest Minnesota.

- There is a level 2 out of 5 risk for severe thunderstorms
  across the region Saturday afternoon into Saturday night.

&&

.UPDATE...
Issued at 1030 AM CDT Fri Jul 12 2024

Attention recently has been on convection still chugging along
in southern MB moving east- southeast. While radar trends
suggest convection is maintaining strength, cloud top
temperature trends via infrared satellite suggests convection is
weakening, particularly on its southern flanks. With this in
mind, confidence in morning guidance`s depiction of weakening of
this convection is medium-high. However, should convection
survive as it nears international border by early afternoon,
there is a chance this convection could reinvigorate given the
building instability and moisture over eastern ND into western
MN.

Should this occur (albeit low chance at the moment), strong to
severe thunderstorms capable of strong winds and hail may be
possible for our are earlier than previously forecast and what
model guidance would suggest (starting in the afternoon rather
than evening).

UPDATE Issued at 626 AM CDT Fri Jul 12 2024

Some sprinkles have developed near the Canadian Border near
Maida with more showers still in Manitoba. Some high based
clouds are slowly moving southward through the valley and west
central Minnesota.

&&

.DISCUSSION...
Issued at 401 AM CDT Fri Jul 12 2024

...Synopsis...

Tricky forecast ahead over the next few days trying to time
convective chances and temps/dewpoints and heat. Upper ridging has
been in place across the west into the central US with westerly to
northwesterly flow pattern aloft. A series of shortwave troughs to
top the ridge and move through the region today through the weekend.
The initial wave to move through the area today which may kick off an
isolated storm this afternoon in an area of theta-e advection into
northeastern ND/far NW MN, however warm air aloft likely to keep the
area capped which is expected to limit storm potential through the
afternoon/early evening.

...Heat And Humidity Builds...
Heat to build across the area today into Saturday with thermal
ridging aloft, and increasing H85 temperatures into the 20s
Celsius. Additionally increasing low level moisture to send
dewpoints into the 70s across much of the area later today into
Saturday. With highs into the upper 80s and 90s, and the higher
dewpoints, heat index values will top out in the 90s to lower
100s across the area. The warmest period is expected Saturday
afternoon. Slightly cooler temperatures can be expected into
Sunday.

...Friday Severe Threat...
A secondary stronger wave to push east tonight through ND and
to fire storms further west across western ND closer to a
developing surface low this evening. That activity is expected
to progress eastward into eastern ND/far western MN late this
evening into the overnight hours for the main severe weather
threat. Deep layer shear around 25-30 kts with 2-3k J/Kg of
instability should allow any activity moving into the
area/developing across the area to sustain itself through the
night. Given elevated nature, and likely storm growth into an
overnight MCS as it develops eastward into the area late
tonight, expect any tornado potential to be near zero with hail
and gusty winds the main severe threats.

...Saturday Severe Threat...
Some lingering activity possible across the north/east into
Saturday and some questions as to how that will impact severe
chances later in the day, especially with advancement of the
upper level wave and placement of the associated sfc low and sfc
troughing. The morning activity may persist into mid-day which
could push the afternoon development further south of the area.
The sfc trough to be in place across west central MN by mid-day
into mid afternoon where initiation could be expected through
the afternoon hours. Therefore tried to keep pops more
broadbrushed through the day and increasing across the
east/south into the afternoon/evening hours with the uncertainty
timing/placement of how things will play out. With the sfc low
in place/boundary and potential for surface-based convection,
possibilities for an isolated tornado exist, however wind/large
hail threat continue to remain more likely.

Some locally heavy rain potential as well with freezing levels
increasing to around 14kft and PWATs into the 1.7 inch range.
Overall storm motion expected to be progressive enough though to
limit any flood potential at this time.

...Sunday and Beyond...
Another threat for severe storms across the area Sunday with
the stronger trough dropping through the region. This troughing
will bring cooler conditions to the area for early next week,
with high pressure building in to the area Tuesday. Highs to
return to the 70s across the area by Tuesday into Wednesday,
with warmer temperatures returning to the forecast by the end of
the forecast period Thursday into Friday.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 626 AM CDT Fri Jul 12 2024

VFR conditions will persist through this evening. Scattered
thunderstorms will develop in the west and move east tonight
starting around 06z and possibly showers continuing through
tomorrow morning.

&&

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

&&

$$

UPDATE...CJ/MM
DISCUSSION...MJB
AVIATION...MM