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000
FXUS63 KFGF 050330
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1030 PM CDT Sun Jun 4 2023

.UPDATE...
Issued at 1022 PM CDT Sun Jun 4 2023

Increased temperatures slightly for tomorrow. Otherwise, the
shower and thunderstorm activity has diminished substantially
this evening, with the main area now located around Lake of the
Woods. Chances will continue to drop as we head into the overnight
hours. Tomorrow we will see further chances for showers and
storms in the afternoon and evening hours.

UPDATE Issued at 618 PM CDT Sun Jun 4 2023

Thunderstorm activity is slowly diminishing in coverage this
evening, but areas around Thief River Falls and the western
Devils Lake Basin continue to see higher chances. Locally heavy
rainfall, frequent lightning and thunder, and brief gusts up to
40mph are possible with some of these thunderstorms. Daytime
heating is driving these thunderstorms, so once that becomes lost
chances dwindle and showers remain. We continued the chances for
scattered thunderstorms through sunset. Further chances tomorrow
afternoon once again.

&&

.SHORT TERM...(This evening through Monday night)
Issued at 308 PM CDT Sun Jun 4 2023

Key Messages:

-Scattered thunderstorms will continue into the early evening, with
a few isolated strong to severe storms possible.

-Hot temperatures prevail today and into tomorrow.

-Another round of scattered thunderstorms is anticipated on Monday,
with coverage and severity being the primary uncertainties.

Discussion...

This afternoon, ridging aloft persists. However, convective
temperatures have been reached and scattered thunderstorms have
developed across much of the region. While any one storm is unlikely
to see strong to severe development, with a plethora of outflow
boundaries and storm scale kinematics at play, an isolated strong to
severe storm will still be possible this afternoon. Instability of
2000+ J/kg is being analyzed by latest RAP mesoanalysis, alongside
low level lapse rates pushing 9 C/km. While instability is highly
favorable for thunderstorm development, overall shear is lacking,
with negligible 0-3 and 0-6 km shear currently being analyzed. Storm
scale interactions may still be enough for isolated strong to severe
thunderstorms to develop though. While widespread severe weather is
not anticipated, any stronger storms that do develop will have the
potential for gusty winds over 40 mph, small hail, brief heavy
rainfall, and frequent lightning.

Furthermore, a weak backdoor front currently to the northeast of the
forecast area is expected to gradually drop southwestward through
the short term period. As this secondary foci for lift approaches,
scattered thunderstorms will continue to be possible over the
northern forecast area through the early evening. This will be the
likely area for strongest thunderstorm development outside of any
storm scale enhanced thunderstorms. Ensemble guidance continues to
hint at a rather progressive progression of the front. Latest RAP
guidance suggests that the front will be draped over the central
forecast area by mid morning Monday, pushing toward the border of
the Dakotas by mid to late afternoon. It should be noted that HREF
depicts a slower trend of the frontal passage though. Regardless, as
this front moves through the region, there will be some potential
for training showers and thunderstorms along the front. Any
deviation from the progressive nature would in turn yield a higher
chance for training to occur. Regardless, any flash flooding would
likely be tied to urban centers.

As the front moves through the region on Monday, there is some
potential to see a very slight downward trend in temperatures. Highs
in the 80s to low 90s are still expected. While the front will
provide the primary mechanism for thunderstorm development, as long
as temperatures rebound, another round of widely scattered
thunderstorms will be possible once convective temperatures are met
Monday afternoon.

.LONG TERM...(Tuesday through Sunday)
Issued at 308 PM CDT Sun Jun 4 2023

Key Messages:

-Warm, above normal temperatures persist through at least the week
ahead, with a potential cool down to near normal by the weekend.

-Chances for showers and storms will be possible each afternoon.

-Near critical fire weather conditions possible late week into the
weekend.

Discussion...

The overall pattern aloft looks to remain somewhat stagnant through
the majority of the week ahead. As a large scale blocking pattern
remains in place, upper level ridging over the northern Plains looks
to be a mainstay. Latest cluster analysis indicates that some
weakening of the ridge will occur toward the middle and latter
portions of the week, before it begins to retrograde westward,
introducing northwesterly flow aloft to the region. This overall
pattern shift will be dictated by a strengthening trough over the
eastern CONUS, meaning that its positioning will be paramount in the
upper level pattern evolution through the long term period.

Prior to the pattern shift though, the weather across much of the
week ahead will look to remain status quo. With weak, but persistent
south-southeasterly flow at the surface, WAA will continue to feed
above normal temperatures and moist air to the region. While the
ridge aloft looks to remain centered over the forecast area,
providing large scale subsidence aloft and a lack of appreciable
shear, afternoon temperatures look to climb into the 80s to low 90s
each afternoon. With convective temperatures generally running in
the mid 80s, diurnal convection is expected each afternoon across a
majority of the CWA. Despite the likely presence of moderate
instability (1000-2000 J/kg), shear will be lacking underneath the
ridge. As a result, widespread organized severe weather is not
anticipated. That being said, a few isolated strong to severe storms
will be possible given any storm scale modifications of the
environment.

As mentioned prior, there is some variability regarding the timing
of northwesterly flow aloft returning to the region. Most ensemble
guidance indicates this pattern shift moving toward the weekend
though. Given the amplified nature of the ridge and the overall
positioning of the northwesterly flow favoring a trajectory toward
the Great Lakes, a brief reprieve from scattered showers and
thunderstorms may be possible across the weekend period. That being
said, any shift in the flow pattern could result in a shortwave
impacting the region and bringing with increasing rain chances.
Cooler temperatures will also be possible around this time frame as
well, with a return to near normal high temperatures in the upper
70s to low 80s anticipated. Accompanying this cool down and
northwesterly flow aloft will be an overall drier air mass.
Minimum RH values dropping into the low 30s look to be accompanied
by at least sustained southeasterly winds, which, depending upon
the condition of fuels, may lead to near critical fire weather
conditions, namely across northwestern and west central Minnesota
that may need to be monitored moving forward.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1022 PM CDT Sun Jun 4 2023

Shower and thunderstorm activity continues to diminish as
instability is lost across the region. Some isolated VCTS is still
possible in TVF through 08z, otherwise just -SHRA. GFK could see
some brief showers through 08z as well. Other areas conditions are
turning dry with light and variable winds.

We should start to see winds turn toward the east around 15-18z,
but remain around 5-10kts sustained. Further chances for showers
and thunderstorms tomorrow afternoon and evening for all
sites. Coverage of showers and storms will be scattered at best.
Otherwise, cloud decks will turn BKN during this time. Some of the
storms could bring gusty winds creating erratic wind changes at
times near and around storms.

&&

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

$$

UPDATE...Spender
SHORT TERM...Rick
LONG TERM...Rick
AVIATION...Spender