Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 240452
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1152 PM CDT TUE AUG 23 2016

.UPDATE...
Issued at 1023 PM CDT Tue Aug 23 2016

Trimmed thunderstorm chances to a slight chance along the Red
River and east, except for Roseau/Kittson/Marshall county areas
this evening. Mesoanalysis shows nearly 25 kts of effective shear.
A storm near Greenbush has shown some strength...but still well
below severe limits. Could see a few cells extend to the south-
southwest to near Fargo before diminishing around midnight or
shortly thereafter.

UPDATE Issued at 607 PM CDT Tue Aug 23 2016

Latest HRRR and NAM runs have convection firing shortly after 7 PM
near a line from Gwinner to Fargo to Roseau. The latest SPC
analysis has 2500-3000 J/kg of MLCAPE from Langdon to Valley
City...and moving eastward. Seeing some weak activity near
Langdon currently. Deep shear should be limited tonight...less
than 20 kts or so...which will limit severe threat somewhat. A
Marginal risk for hail and damaging wind from SPC remains in
effect this evening across NW and west-central MN as well as
Richland and Cass counties in ND. Will monitor for severe weather
potential this evening.

&&

.SHORT TERM...(This evening through Wednesday)
Issued at 310 PM CDT Tue Aug 23 2016

Main forecast challenge is thunderstorm potential along the sfc
cold front late this afternoon into the early evening. As of 245
pm, thicker clouds were located west of a line from Valley City to
Crookston to Baudette. There have been a few elevated showers in
this area too, which both have helped hold temps down a few
degrees today. There could still be a quick boost in temps as
winds turn SW and then West prior to the frontal passage. Areas
along and east of the Red River remain in a marginal risk for
severe weather per the latest SPC day 1 outlook. SPC mesoanalysis
page shows very warm 700mb temps over the FA, generally +12C or
so, helping to cap convection so far. The main 500mb low remains
over southwest Saskatchewan, with the better upper support and
0-6km bulk shear over western ND, or lagging behind the sfc
front. The core of the low level jet has shifted into NW MN, with
a few elevated echoes around or NE of KGFK.

All these elements do not come together, hence the marginal
severe risk. The latest high resolution models show some shower
and tstm development along the cold front by 5 to 6 pm, from south
of KGFK to around Valley City. They hold this line together as it
moves into northwest MN during the early evening. There could be a
few strong to severe storms, but the window will be fairly short.
Other than the storms, south winds ahead of the cold front will
stay gusty into the evening, and behind the front northwest winds
will be the same way over the Devils Lake region. Winds should
decrease by mid to late evening, then increase again by mid to
late morning Wednesday. There could still be a few showers around
Wed afternoon, but mainly in the Devils Lake region.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 310 PM CDT Tue Aug 23 2016

Forecast challenges throughout the next week will be trying to time
any precipitation chances, with the best chance Friday night and
into Saturday.

The period begins with a deep 500 mb low situated just north of the
international border. Vorticity max swinging around the base of this
feature will allow precipitation chances to linger across the
extreme northern forecast area through roughly Thursday afternoon.
The remainder of the area should be dry, cloudy, and cool as
temperatures will struggle to reach the lower 70s, especially east
of the valley. Skies will quickly clear from west to east by
Thursday evening allowing temperatures to drop into the upper 40s.

As the upper low pulls away and towards the upper Great Lakes on
Friday, the area will transition back to slightly warmer southwest
flow. Sunshine early in the day will give way to highs back into the
mid to upper 70s. A stronger wave will then swing through the
Northern Plains with precipitation chances returning across central
North Dakota by late Friday afternoon and spreading eastward
throughout the first half of the weekend.

Southwesterly midlevel flow pattern will persist the rest of the
period with weak waves contributing to on and off precipitation
chances. Broadbrushed slight chance to chance PoPs will have to
suffice for now as not confident enough to pick out the best timing
yet. Temperatures will return to seasonable values in the upper 70s
to around 80.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1152 PM CDT Tue Aug 23 2016

This set of TAFs has some mist in the BJI TAF as indicated by the
NAM MOS guidance and recent trends. Believe it will be short lived
as drier air will push into the area behind the cold front
tonight. There are some MVFR Cigs ahead of the front...which is
currently near the ND/MN border. Tomorrow...breezy west winds are
expected along with some fair weather cumulus in the afternoon.
Thicker cumulus can be expected up near DVL...with a shower
possible. Most of the showers should stay to the north of DVL,
however.

&&

.FGF Watches/Warnings/Advisories...
ND...None.
MN...None.
&&

$$

UPDATE...Knutsvig
SHORT TERM...Godon
LONG TERM...Lee
AVIATION...Knutsvig



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