080 
FXUS63 KFGF 210259
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
959 PM CDT Fri Aug 20 2021

.UPDATE...
Issued at 959 PM CDT Fri Aug 20 2021

The mid/upper low center has transitioned to the International
Border and the strongest winds are now confined to the northwest
part of the Devils Lake Basin. I trimmed counties from the warning
to the east and south and may be able to end it in a few hours
depending on how things trend. Otherwise, most
showers/thunderstorms are ending outside of our far east and
northwest and are much weaker. The severe threat has ended and
 the heavy rain threat appears to be diminished. As the upper low
transitions eastwards through southern Manitoba tonight scattered
showers may moved back over our north (north of Highway 2) 
through Saturday morning. A few moderate to heavy showers can't be
ruled out as PWATs remain 1-1.5 inches, however there will be 
minimal instability and better forcing may remain north. I 
adjusted PoPs/Wx to match current trends.

UPDATE Issued at 710 PM CDT Fri Aug 20 2021

A possible sting jet associated with strong closed mid-upper low,
combined with region of strong subsidence and increasing pressure
gradient is resulting in wind gusts as high as 60 mph based on
reports west of the RRV and the southern Devils Lake Basin. These
winds are not associated with the thunderstorm activity, but could
still cause impacts through the evening hours as this upper low
transitions northward. I issued a High Wind Warning to cover this
threat through 06Z (1 AM) tonight, though conditions may improve
earlier. 

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 332 PM CDT Fri Aug 20 2021

Convection strength and type remain the main challenges for the 
period.

Main upper trough is still out around the Montana border, but the
surface low has developed just west of our counties and there 
seems to be a weak secondary low developing over southeastern ND.
Plenty of ML CAPE over 1500 J/kg extending all the way up towards
the international border in northwestern MN, with deep layer bulk
shear around 35 to 40 kts. Storms have formed in a line along a 
weak lead shortwave and warm air advection across our far eastern 
tier of counties, with more discrete cells developing behind it 
along the southern Red River and Sheyenne Valleys ahead of the 
main surface low center. CAMs continue to show signs of some 
congealing into a somewhat broken line as the surface low lifts 
northeast late this afternoon and evening. This seems reasonable 
given increasing forcing as the main trough ejects eastward and 
the cold front pushes into our area. 

As the convective activity pushes northeastward this afternoon and
evening, there should be a dry slot making its way into portions
of our counties. There is good agreement with the short range
ensembles for some deformation zone showers mainly in our
northwestern counties. These showers will continue in our north
through the overnight hours and even along the international
border into Saturday, long past the point where convection has 
moved out of our area. Breezy northwest winds and cold air
advection for the rest of the region tomorrow, with much cooler
highs in the 60s to low 70s and drier air behind the surface low.
Temps Saturday night will be fairly cool, down into the 40s and
low 50s with winds shifting back to the southeast. 

.LONG TERM...(Sunday through Friday)
Issued at 332 PM CDT Fri Aug 20 2021

A few chances for storms and rain will be possible across the long 
term as a cooler and more active weather pattern persists. The first 
opportunity comes on Sun with the next chance arriving on Tue. 

The underlying conditions across the long term are expected to favor 
cooler, below normal temperatures. This is supported by 850 hPa 
temperatures generally in the teens and low relative H5 heights as 
well. The main question mark for Sun will be the magnitude of return 
flow into the area. Current forecasted highs in the upper 60s to mid 
70s are anticipated with forecasted dewpoint temperatures recovering 
into the low 60s. A resultant narrow corridor of instability in 
conjunction with ample shear may be supportive of a few strong 
thunderstorms Sun aftn into the eve. Rainfall totals, as a result, 
will vary spatially and be locally higher with any thunderstorms 
that may develop. Current ensemble guidance is indicating a 70 to 
80% chance for rainfall accumulations greater than or equal to 0.1" 
across eastern North Dakota and into northwestern Minnesota. 

The active weather pattern is likely to persist into the week ahead. 
Southwesterly flow aloft will continue to steer any embedded 
shortwave systems in the general direction of the northern Plains as 
a result. The next prospective shortwave and attendant rainfall 
chance is then progged to arrive on Tue. This looks to be a much 
weaker wave with less upper level support and moisture return as the 
Sun system. Thus, impacts look to be on the lower end at this time, 
but will continue to monitor this system moving forward.
Otherwise, cool, below normal high temperatures in the 60s to 70s 
are expected to be a mainstay throughout the remainder of the long 
term period. 

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 636 PM CDT Fri Aug 20 2021

Clusters of showers and thunderstorms have transitioned over
northeast ND, west central and northwest MN. There is a clearing
trend in southeast ND and trends should be fore activity to end
this evening from the southwest to northeast, though a few showers
or weaker thunderstorms may linger in the Devils Lake Basin later
into the night. Brief IFR conditions are possible with 
thunderstorm activity, along with erratic stronger winds. Severe 
potential is lingering for a few more hours with thunderstorm 
activity. Several areas of MVFR stratus will continue to fill in 
and persist through the remaining TAF period across eastern ND and
northwest MN. Surface low pressure and several frontal passages 
are going to result in shifting winds from the southeast to the 
west-northwest and occasional gusts 20-35 kt.


&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...High Wind Warning until 1 AM CDT Saturday for NDZ006-007-014-015-
     024-026-054.

MN...None.
$$

UPDATE...DJR
SHORT TERM...JR
LONG TERM...WJB
AVIATION...DJR