Area Forecast Discussion
Issued by NWS Grand Forks, ND

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679
FXUS63 KFGF 201808
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
108 PM CDT Thu Jul 20 2017

.UPDATE...
Issued at 103 PM CDT Thu Jul 20 2017

Area of mid level showers (what was t-storms) moving into NW MN at
18z near a Bagley to Hallock line. RAP/HRRR finally caught on and
has this narrow area moving east the rest of the aftn so coord
with DLH and spread sct rw/trw wording east in a narrow zone.

Otherwise plenty of sunshine and temps rebounding into the low-mid
80s in sunny areas. Updated day 1 SPC outlook and trends would
indicate severe risk far W ND mid to late aftn then some risk of
these storms moving into E ND late evening and then possibly a bit
more coverage late night in warm adv zone nr the Canadian border.


&&

.SHORT TERM...(Today and tonight)
Issued at 300 AM CDT Thu Jul 20 2017

Weak mid-level frontogenesis combined with instability/steep lapse
rates at the level of forcing enough to produce showers/thunder
near Minot. Anticipate this forcing into the Devils Lake Basin
during the early morning hours with showers and isolated thunder
possible.

Given yesterday`s rain along with light winds, patchy fog
possible across a portion of the region during the early morning
hours.

High pressure will propagate across the region today advecting in
a stable airmass (light winds and mostly sunny sky with
temperatures in the 80s).

Return flow commences tonight. Most guidance signals an upper
level wave to induce mid-level frontogenesis/warm air advection
near the International border with thunderstorms possible during
the overnight hours. MUCAPE is weak, but deep layer shear is
strong...could be marginally severe storms.

.LONG TERM...(Friday through Wednesday)
Issued at 300 AM CDT Thu Jul 20 2017

Friday-Saturday...Guidance is all over the place regarding
convective details during this timeframe. Convective parameters
will be in place to support severe storm potential. Of course,
much of the severe potential is dependent on heating and
timing/location of embedded shortwaves. Most likely scenario at
this point is for isolated severe storms Friday afternoon/evening,
and then an organized MCS just ahead of an upper low approaching
the region from Canada moving into the forecast area after dark.

The upper low passes just northeast of the region on Saturday,
with weaker showers/thunder possible across northwest Minnesota.
Saturday should be a cooler and breezy day (increased winds around
5 knots over the model blend west of the valley Saturday
afternoon).

Sunday-Wednesday...For Sunday, the Euro still hints at late
showers exiting northwest Minnesota early in the morning, but the
other model solutions generally agree that Sunday will be dry with
some sunshine as high pressure builds in from the north. With
northerly flow setting up in lower levels and aloft, Sunday looks
to be mild with highs in the 70s. For Monday return flow develops
behind the high, still yielding another dry and warm summer day.

For the middle of next week, the Euro/GFS solutions are still in
pretty good agreement regarding a frontal/upper trough passage in
the Tuesday/Tuesday night timeframe. This would bring chances for
showers and thunderstorms across the area during this period.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 103 PM CDT Thu Jul 20 2017

Cloud bases will remain VFR thru the pd. Will need to watch for
any shower or t-storm near any airport/landing site and locally
variable winds.

&&

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

$$

UPDATE...Riddle
SHORT TERM...TG
LONG TERM...TG/BP
AVIATION...Riddle



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