Area Forecast Discussion
Issued by NWS Grand Forks, ND

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206
FXUS63 KFGF 191510
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1010 AM CDT Wed Jul 19 2017

.UPDATE...
Issued at 1008 AM CDT Wed Jul 19 2017

Severe storm moving southeast thru eastern SD south of Aberdeen.
Analysis would indicate main severe risk today considerably
farther south into EC SD into southern MN. Meanwhile storms moved
ESE out of Manitoba and will move thru nrn fcst area thru early
aftn.  Highlighted highest pops far north and the far south.

&&

.SHORT TERM...(Today and tonight)
Issued at 348 AM CDT Wed Jul 19 2017

Shortwave energy moving east into North Dakota from Montana will be
the initial focus for thunderstorm chances this morning. Favorable
effective shear and moisture and modest instability reside in
western ND, in closer proximity to the surface low, allowing for
storm development early this morning. Expect initial isolated to
widely scattered storms to form in north central North Dakota,
gradually tracking east into the Devils Lake basin area and
northeast North Dakota early this morning. The CAMs indicate that a
few strong to severe thunderstorms are possible in this area with
the main threats being hail to one inch in diameter and gusts to 60
mph.

By mid to late morning, surface based instability will begin
development and the warm front will begin working north into the
southern Red River valley. Additional shower and storm development
in central North Dakota will gradually move into eastern North
Dakota. Many CAMs suggest this development will eventually collide
with warm front forcing in the central valley, yielding thunderstorm
activity strengthening into the strong to severe discrete cells and
eventually a complex of storms moving southeast through the southern
Red River valley in the afternoon. These discrete cells and complex
would have the strongest threats with hail over 2 inches in
diameter, damaging gusts to 75 mph, and tornadoes possible. Heavy
rainfall is a notable concern as well with precipitable water
values maxing at 1.5 to 2.0 inches this afternoon, especially over
areas in west central MN that received several inches of rain
recently. Additionally, there is some potential for additional
storm development behind the main complex in the middle to late
afternoon in the central to southern Red River valley, but this is
very uncertain at this time.

.LONG TERM...(Thursday through Tuesday)
Issued at 348 AM CDT Wed Jul 19 2017

Thursday-Friday...Weak ridging within zonal flow will lead to a dry
day on Thursday with temperatures near to above normal values.
Return flow commences Thursday night with weak shortwaves possible.
For Thursday night, most guidance suggests axis of instability will
remain across western North Dakota and that any early morning
activity should be weakening as it enters eastern North Dakota.
Although details are still uncertain, the potential does exist for
strong to severe storms Friday afternoon/evening as the axis of
instability propagates over the region with strong deep layer shear
in place.

Saturday-Monday...A stronger upper level wave will propagate
southeast across Canada into the Great Lakes region. This will
spread a cooler and drier airmass into the region. A few showers
will be possible across northwest Minnesota Saturday afternoon.
The airmass behind this system will be much cooler, and ridging
will lead to below normal temperatures on Sunday and Monday (with
dry weather).

Tuesday...Most guidance is in agreement suggesting upper flow
becoming zonal with the next series of upper waves bringing shower
and thunderstorm chances.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 643 AM CDT Wed Jul 19 2017

VFR conditions expected through most of the TAF period. Mid to
high level cigs expected through much of the day as scattered
showers and storms move southeast through the area. With
uncertainty regarding exact locations/timing of storm development,
left vicinity mention for now. Greatest coverage will likely be
along/south of a DVL-GFK-BJI line in the afternoon. Expect cigs to
gradually clear out this evening from northwest to southeast.


&&

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

$$

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



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