Area Forecast Discussion
Issued by NWS Grand Forks, ND

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148
FXUS63 KFGF 201135
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
635 AM CDT Thu Jul 20 2017

.UPDATE...
Issued at 635 AM CDT Thu Jul 20 2017

Observation sites continue to report on and off dense fog, area
web cams also indicate this patchy dense fog. These conditions
will improve quickly now that we are after sunrise.

Shower/thunder across a portion of the Devils Lake basin should
continue for a few more hours. One cell did get to near severe
limits, but do not expect anything stronger given weakening
instability.

Forecast is in good shape so far.

&&

.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 12Z TAFS through 12Z Friday morning)
Issued at 635 AM CDT Thu Jul 20 2017

VFR conditions expected through the period. Light winds today.
Isolated thunderstorms possible (especially later tonight west of
the Red River Valley), but limited coverage prevents mentioning in
the TAF.

&&

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

$$

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



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