Severe Thunderstorm Warning 138, NWS Grand Forks, ND

Area Forecast Discussion
National Weather Service Grand Forks ND
352 PM CDT Wed Jul 17 2019

.MESOSCALE DISCUSSION...
Issued at 349 PM CDT Wed Jul 17 2019

Thunderstorms, including a few severe thunderstorms, remain likely
from the Red River Valley eastward into northwest Minnesota late
this afternoon and into the evening hours. Main threats remain
strong winds and hail up to 1.5 inches with the strongest storms. A
tornado or two can't be ruled out. The most likely location for
severe storms is across northern Minnesota this afternoon and
evening.

Recent visible satellite imagery shows convective initiation underway
across northern Minnesota. Storms are initiation off a surface
confluence axis oriented northwest to southeast. With deep layer
shear nearly off this boundary, discrete supercells are likely over
the next one to two hours. However, a nearly straight hodograph will
encourage splitting storms and storm interactions, and possibly
upscale growth, heading into the evening hours. With backed surface
winds noted in Roseau and Lake of the Woods counties, a tornado
threat can't be ruled out as storms become more developed over the
next couple of hours.

Convective initiation is also trying to become established across
far northeast ND and along the international border where forcing is
slightly better closer to the upper level low. But again, robust
initiation has not yet occurred.

Further south, the surface trough/boundary has effectively mixed out
as denoted by southwesterly surface winds. Despite the daytime
heating with temperatures reaching into the 80s, the lack of
vertical development in the cumulus field is indicative of capping
that is preventing storm development.

For the next few hours, attention will be focused on northern MN
where storm initiation seems most likely. 1-2 kJ/kg of MLCAPE, 30-40
knots of effective bulk shear, and 100-200 m2/s2 ESRH will maintain
a severe threat over the next few hours. Hail and strong winds
remain the greatest threat, but a tornado can't be ruled out
entirely.

&&

.SHORT TERM...(This afternoon through Thursday night)
Issued at 349 PM CDT Wed Jul 17 2019

Thunderstorm coverage tied to peak heating underway and may continue
to expand before transitioning east this evening. Another mid level
impulse tracks east into our region overnight, with additional
showers/storms possibly moving into Devils Lake region (should be
weaker with less supportive mid level lapse rates/elevated
instability). Progressive pattern remains in place Thursday-Thursday
night, and trough axis along Red River could act as focus for
additional thunderstorm development with severe possible
(instability recovering along/ahead of approaching shortwave trough.
This trough is potentially stronger. While severe coverage is
uncertain (depending on destabilization/recovery), actual
shower/storm coverage could end up being better as this fast moving
feature tracks across our CWA.

Regarding temps: Near seasonal values (lows in lower 60s/highs in
the low to mid 80s).

.LONG TERM...(Friday through Wednesday)
Issued at 349 PM CDT Wed Jul 17 2019

For Friday through Saturday, a upper level zonal flow pattern
continues to bring a somewhat active weather pattern to the Northern
Plains. Overall this looks to be a drier period in the forecast for
areas north of Hwy 200, but across southeast ND and west central MN,
chances for showers and storms develop early Friday and through the
day Saturday. Despite the off and on rain chances, these days do not
look to be a complete wash.

The next widespread rain chances build back into the region for
Saturday night through Sunday night as an impulse aloft traverses
through the region in northwest flow aloft, but there is low
confidence in any details regarding potential for severe weather at
this time.

Through the weekend and into early next week, upper ridging in the
South breaks down and strong ridging builds over the Rockies, giving
way for cooler air to infiltrate the region in northwest flow aloft.
Through early next week, expect to see temperatures near normal
values with daytime highs in the 70s to lower 80s and overnight lows
in the 50s to lower 60s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 100 PM CDT Wed Jul 17 2019

Showers lingering along International Border remaining north of
terminals, however further development of showers/thunderstorms
still possible after 21Z today with threat winding down 01-03Z.
Best chance for thunderstorm (or strong thunderstorms) may be
from KFAR to KTVF to BJI, but coverage of thunderstorms may remain
scattered and direct impacts at terminals less certain. There is
a little more consensus at KBJI where I included TEMPO. Pockets
of MVFR CU still linger over the area with a few locations as low
as 1500 FT AGL. Trend should be towards prevailing VFR this
afternoon with restrictions then tied to shower/thunderstorm
activity.

&&

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

MESOSCALE...AM
SHORT TERM...DJR
LONG TERM...BP
AVIATION...DJR

Hazardous Weather Outlook
National Weather Service Grand Forks ND
402 PM CDT Wed Jul 17 2019

MNZ040-NDZ006-007-014-015-024-026-028-029-038-049-052>054-182115-
Grant-Towner-Cavalier-Benson-Ramsey-Eddy-Nelson-Griggs-Steele-
Barnes-Ransom-Sargent-Richland-Western Walsh County-
402 PM CDT Wed Jul 17 2019

This hazardous weather outlook is for portions of eastern North
Dakota and west central Minnesota.

.DAY ONE...This Afternoon and Tonight

Isolated severe thunderstorms will be possible across parts of
eastern North Dakota, west central Minnesota, and northwest
Minnesota through this evening. The main hazards will be large
hail up to 1.5 inches and damaging wind gusts up to 70 mph.
Isolated tornadoes are also possible. Very heavy rainfall is also
possible with the storms.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Isolated severe thunderstorms are possible across northwest
Minnesota. The main hazards will be large hail up to quarter size
and damaging wind gusts up to 60 mph. Isolated tornadoes are also
possible.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

MNZ001>009-013>017-022>024-027>032-NDZ008-016-027-030-039-182115-
West Polk-Norman-Clay-Kittson-Roseau-Lake Of The Woods-
West Marshall-East Marshall-North Beltrami-Pennington-Red Lake-
East Polk-North Clearwater-South Beltrami-Mahnomen-
South Clearwater-Hubbard-West Becker-East Becker-Wilkin-
West Otter Tail-East Otter Tail-Wadena-Pembina-
Eastern Walsh County-Grand Forks-Traill-Cass-
402 PM CDT Wed Jul 17 2019

This hazardous weather outlook is for portions of eastern North
Dakota, west central and northwest Minnesota.

.DAY ONE...This Afternoon and Tonight

Scattered severe thunderstorms will be possible across parts of
northeast North Dakota and northwest Minnesota through this
evening. The main hazards will be large hail up to 1.5 inches and
damaging wind gusts up to 70 mph. Isolated tornadoes are also
possible. Very heavy rainfall is also possible with the storms.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Isolated severe thunderstorms are possible across northwest
Minnesota. The main hazards will be large hail up to quarter size
and damaging wind gusts up to 60 mph. Isolated tornadoes are also
possible.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

Special Weather Statement
National Weather Service Grand Forks ND
331 PM CDT Wed Jul 17 2019

MNZ005-006-009-172130-
North Beltrami MN-Roseau MN-Lake Of The Woods MN-
331 PM CDT Wed Jul 17 2019

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN ROSEAU...
NORTHWESTERN BELTRAMI AND SOUTHWESTERN LAKE OF THE WOODS COUNTIES
UNTIL 430 PM CDT...

At 330 PM CDT, Doppler radar was tracking a strong thunderstorm 8
miles west of Gates Corner, or 32 miles south of Roseau, moving
northeast at 20 mph.

Nickel size hail and winds in excess of 40 mph will be possible with
this storm.

This strong thunderstorm will be near...
  Gates Corner around 355 PM CDT.
  Norris Camp around 430 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Grand Forks.

&&

LAT...LON 4834 9549 4844 9561 4844 9560 4873 9515
      4851 9491
TIME...MOT...LOC 2030Z 234DEG 17KT 4841 9550

CJ