Severe Thunderstorm Warning 112, NWS Grand Forks, ND

Area Forecast Discussion
National Weather Service Grand Forks ND
1143 PM CDT Wed Jul 26 2023

.UPDATE...
Issued at 1140 PM CDT Wed Jul 26 2023

500 mb short wave trough moving thru the RRV. Strongest piece
moving thru eastern Manitoba with a weaker piece into eastern SD
attm. Unstable airmass remains just above the surface and just
enough to generate elevated t-storms. Every so often getting a few
pulse severe storms with hail threat. Had one earlier east of
Bismarck and have some newer storms along an outflow intensfying
near Crookston. Whole area moving east with individual storm
motion 35 kts.

UPDATE Issued at 657 PM CDT Wed Jul 26 2023

A few storms formed in area south of Bismarck earlier in area
where sfc temps reached just over 100F. Most of the storms
remained elevated and not severe, exception is one left moving one
which got supercell characteristics with strong tilt and some
rotation. SPC meso page does have a little area where left moving
supercells were favored in this zone. Otherwise MLCAPE is
considerbly less as it moves north of Jamestown. So uncertain how
long it will maintain supercell characteristics with hail and 60
mph wind threat. Otherwise other activity along the SD border is
quite weak but should move into SE ND along the border into our
cwa 02z or so. Not anticipating much intensification.

&&

.SHORT TERM...(This afternoon through Thursday)
Issued at 311 PM CDT Wed Jul 26 2023

-Heat index values near 100F are occuring ahead of an approaching
front. These are brief/localized in nature so an advisory is not
being considered at this time.

-Isolated severe thunderstorms are possible this evening, possibly
into the early overnight period. Early in the event supercells may
support large hail around golf ball size or larger, along with
strong winds 60 mph. The tendency though will be for less organized
clusters and more common severe impacts in the 1"/60 mph range.

A surface trough axis (possible dry line) is moving towards our
forecast area this afternoon with a 10F spread in Td values on
either side of this boundary. Convergence is relative weak, so to
break the strong cap in place it will likely take help from the mid
level waves approaching the region. One wave of interest is in
western SD where a shallow CU field is starting to develop upstream.
As this wave moves east towards the SD border additional height PVA
occurs as a stronger wave/jet streak moves into southern Manitoba
(this evening-overnight). The main cold front arrive later tonight
into Thursday morning. Between these features it is possible we have
just enough support to break the CAP before sunset. Any activity
then becomes elevated as the main wave tracks east after sunset and
forcing increases with the main frontal passage. This scenarios is
most favored toward the southern PV area on WV as shown by RAP to
track towards SE ND. HRRR/WRF had been consistent in showing a
cluster forming towards our south and tracking east, but once the
CAP breaks I would rule out additional clusters forming due to
outflow/cold pool interactions.

Very unstable air mass (MLCAPE 3000+ J/KG) is in place along the
moist Td axis in the RRV. Combined with effective values 35kt, we
may initially see supercells, but with weaker low level shear and
higher bases where development occurs this would mainly result in
larger hail (1.75"+) and 60mph+ wind potential (particularly with
higher DCAPE in our south). As thunderstorms cluster up or
eventually become elevated, the threats should transition to 1"
hail/60 mph winds for the remainder of the event.

.LONG TERM...(Friday through Wednesday)
Issued at 311 PM CDT Wed Jul 26 2023

-There should be a trend towards seasonal temperatures Friday
through much of next week.

-Progressive waves keep shower and thunderstorm chances in the
forecast through the middle of next week, however there is higher
variability in coverage/impacts due to the nature of these waves.
There is a lower probability (less than 5%) for severe potential
Monday and Tuesday.

There is strong consensus and clustering regarding the evolution of
the larger scale pattern through the long range periods, with the
southern CONUS ridge "flattening" and quasi-zonal flow developing
across the Northern Plains/Upper Midwest. This pattern keeps higher
heights and stronger southerly flow south and tends to favor
seasonal temperatures (within 5F of averages). This pattern also
supports progressive shortwave passages that are much more variable
in nature between ensemble members/systems. This keeps near daily
potential for showers/storms, but lowers confidence on details. GEFS
based machine learning does show a 5% severe potential Monday and
Tuesday next week, however NBM CWASP which reflects a combination of
ensemble systems does not highly any specific period for severe
potential which makes sense considering the larger spread between
details in these fast moving waves.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1140 PM CDT Wed Jul 26 2023

Outside of individual t-storms, VFR thru the pd with area of mid
and high clouds.

&&

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

UPDATE...Riddle
SHORT TERM...DJR
LONG TERM...DJR
AVIATION...Riddle

Hazardous Weather Outlook
National Weather Service Grand Forks ND
822 AM CDT Wed Jul 26 2023

MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024-
026>030-038-039-049-052>054-271330-
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-Grant-Towner-Cavalier-
Pembina-Benson-Ramsey-Eastern Walsh-Eddy-Nelson-Grand Forks-
Griggs-Steele-Traill-Barnes-Cass-Ransom-Sargent-Richland-
Western Walsh-
822 AM CDT Wed Jul 26 2023

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

.DAY ONE...Today and Tonight

Isolated severe thunderstorms are possible across much the region
this afternoon and evening. The main hazards associated with the
strongest storms will be large hail up to half dollar and
damaging wind gusts up to 60 mph.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Isolated severe thunderstorms are possible across portions of the
region on Thursday, primarily along and south of I 94. The main
hazards will be hail up to 1 inch and wind gusts to 60 mph.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

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Special Weather Statement
National Weather Service Grand Forks ND
1150 PM CDT Wed Jul 26 2023

MNZ006-008-009-013-014-016-270530-
East Marshall MN-Red Lake MN-North Beltrami MN-Pennington MN-
North Clearwater MN-Lake Of The Woods MN-
1150 PM CDT Wed Jul 26 2023

...Strong thunderstorms will impact portions of southeastern
Marshall, northeastern Red Lake, northwestern Beltrami, eastern
Pennington, southeastern Lake of the Woods and northwestern
Clearwater Counties through 1230 AM CDT...

At 1150 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Gates Corner to near High Landing.
Movement was east at 40 mph.

HAZARD...Winds in excess of 40 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Plummer, Grygla, Goodridge, Thorhult, Carmel, Malcolm and High
Landing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4856 9458 4801 9501 4790 9610 4844 9555
TIME...MOT...LOC 0450Z 263DEG 36KT 4840 9535 4800 9589

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH

Lynch

Preliminary Local Storm Report
National Weather Service Grand Forks ND
1227 AM CDT Thu Jul 27 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1207 AM     Hail             2.5 SSW Mentor          47.66N 96.17W
07/27/2023  M1.00 inch       Polk               MN   Cocorahs

            Report of 1 inch hail, duration about 5
            minutes. Time estimated using radar.

&&