Severe Thunderstorm Warning 137, NWS Bismarck, ND

Area Forecast Discussion
National Weather Service Bismarck ND
513 PM CDT Sat Jul 4 2020

.UPDATE...

Issued at 511 PM CDT Sat Jul 4 2020

With heavy thunderstorms across my four southeast counties, we
opted to issue a Flash Flood Watch for Logan, McIntosh, LaMoure,
and Dickey counties until midnight.

UPDATE
Issued at 445 PM CDT Sat Jul 4 2020

See mesoscale discussion below for convective details in the short
term.

Severe thunderstorm watch number 328 is in effect now through this
evening for far south central ND and for much of the James River
Valley. Will monitor radar trends for storms southeast now through
early evening and for storms moving in from Montana later this
evening for further product updates late this afternoon and
through this evening. Storms may also cross into far northern ND
this evening so have kept POPs here. Removed POPs for much of
central North Dakota this evening as most likely scenario for
those areas will be overnight showers/storms.

&&

.MESOSCALE DISCUSSION...
Issued at 424 PM CDT Sat Jul 4 2020

Convection has initiated a little earlier than expected along a
remnant outflow boundary from just east of Linton to Edgeley. SPC
Mesoanalysis indicates uncapped SBCAPE around 4500 J/kg, but only
around 30 kts of effective bulk shear at most. Initial storms have
briefly shown supercell characteristics, but the overall trend has
favored pulse-severe, multicell clusters. Very large hail and
damaging winds are expected to be the main threats. At least through
the rest of the afternoon, the tornado threat appears low with only
10 kts 0-1 km bulk shear at most and negligible 0-500 m SRH.
However, outflow boundary interactions may briefly enhance low level
vorticity for stretching potential. An additional threat that will
have to be watched is the potential for training convection leading
to localized flash flooding given slow storm motions and strong low
level moisture transport perpendicular to the remnant outflow
boundary storms have initiated on.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 147 PM CDT Sat Jul 4 2020

There will be two main areas of strong to potentially severe
storms that will impact western and central North Dakota this
evening and tonight. One will likely be ongoing over the James
River Valley, with thoughts generally unchanged from the previous
forecast update.

Another area of storms will be approaching the southwest, ahead of
an advancing cold front around or after 03z, likely in the form
of a forward propagating MCS. Strong instability will be in place
as this area of storms spreads north and east across the state
through the night. Shear will generally be marginal (effective
values 30 to 40 knots), but should be sufficient for a handful of
severe wind and/or hail reports. This activity will likely
diminish as the low level jet relaxes Sunday morning.

The front will move into the eastern third of North Dakota by
Sunday afternoon where strong storms are expected to fire once
again. The best chance of a severe storm will be across the
southern James River Valley, with large hail and damaging wind
gusts being the main threats.

.LONG TERM...(Monday through Saturday)
Issued at 147 PM CDT Sat Jul 4 2020

For the remainder of the period, a mid level trough will set up
across the Pacific northwest, sending multiple shortwaves into the
Northern Plains. Nearly every day will see at least some chances
for showers and thunderstorms. However, at the moment it appears
that the strongest wave will come through Tuesday night through
Wednesday, a period we will have to keep an eye on closely for
severe weather and heavy rain potential. Additionally, 12z CIPS
analogs show a fairly strong signal for severe weather during this
time frame. Plenty of time for things to change with regards to
specific details, but this wave is currently forecast to have a
better CAPE/shear overlap than we have seen in recent events.
Thus, the active stretch continues with above average temperatures.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1204 PM CDT Sat Jul 4 2020

This afternoon will start out mainly dry with showers and
thunderstorms forming mainly in the James River Valley in the late
afternoon or early evening. These storms could become rapidly
severe, most likely impacting KJMS. Large hail and damaging winds
will be the primary threats but a tornado or two is not out of the
question. More storms will enter the west tonight and into Sunday
morning and spread across the central. These storms may also
produce damaging winds and large hail. Any stronger storm may lead
to brief MVFR/IFR conditions, but VFR conditions are expected
outside of any storms or heavier showers.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until midnight CDT tonight for NDZ047-048-050-
051.

&&

UPDATE...NH
SHORT TERM...ZH
LONG TERM...ZH
AVIATION...ZH

Hazardous Weather Outlook
National Weather Service Bismarck ND
514 PM CDT Sat Jul 4 2020

NDZ036-037-046>048-050-051-052215-
Kidder-Stutsman-Emmons-Logan-La Moure-McIntosh-Dickey-
514 PM CDT Sat Jul 4 2020

This Hazardous Weather Outlook is for portions of south central
North Dakota and southeast North Dakota.

.DAY ONE...Tonight

Thunderstorms will develop across the James River Valley late this
afternoon and into the evening.

The stronger storms will have ping pong ball size hail and winds
gusting to 60 mph. A tornado or two will also be possible.

Flash flood watch in effect through this evening for Logan,
McIntosh, LaMoure, and Dickey counties for several rounds of heavy
thunderstorms.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Numerous thunderstorms are forecast across western and central
North Dakota Sunday. Heavy rain is possible with any storm,
especially across the east central. Severe weather is also
possible.

Daily chances for thunderstorms continue mainly Tuesday through
Thursday. Some storms may be severe.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report severe weather to law
enforcement or the National Weather Service in Bismarck.

NDZ001>005-009>013-017>023-025-031>035-040>045-052215-
Divide-Burke-Renville-Bottineau-Rolette-Williams-Mountrail-Ward-
McHenry-Pierce-McKenzie-Dunn-Mercer-Oliver-McLean-Sheridan-Wells-
Foster-Golden Valley-Billings-Stark-Morton-Burleigh-Slope-
Hettinger-Grant-Bowman-Adams-Sioux-
514 PM CDT Sat Jul 4 2020 /414 PM MDT Sat Jul 4 2020/

This Hazardous Weather Outlook is for portions of north central
North Dakota, northwest North Dakota, south central North Dakota,
southeast North Dakota, and southwest North Dakota.

.DAY ONE...Tonight

Thunderstorms will once again develop in western North Dakota
this evening and move east overnight.

The stronger storms will have ping pong ball size hail and winds
gusting to 60 mph tonight.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Numerous thunderstorms are forecast across western and central
North Dakota Sunday. Heavy rain is possible with any storm,
especially across the east central. Severe weather is also
possible.

Daily chances for thunderstorms continue mainly Tuesday through
Thursday. Some storms may be severe.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report severe weather to law
enforcement or the National Weather Service in Bismarck.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BISMARCK ND
456 PM CDT SAT JUL 4 2020

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

0358 PM     HAIL             4 NNE KULM              46.35N 98.92W
07/04/2020  M1.00 INCH       LAMOURE            ND   TRAINED SPOTTER

&&

MH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BISMARCK ND
457 PM CDT SAT JUL 4 2020

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

0449 PM     HAIL             3 SW FREDONIA           46.30N 99.14W
07/04/2020  E1.25 INCH       LOGAN              ND   PUBLIC

            REPORT RECEIVED VIA SOCIAL MEDIA.

&&

JNS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BISMARCK ND
538 PM CDT SAT JUL 4 2020

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

0530 PM     HAIL             1 N KULM                46.32N 98.95W
07/04/2020  E1.50 INCH       LAMOURE            ND   LAW ENFORCEMENT

            REPORT RELAYED BY EMERGENCY MANAGEMENT.

&&

MH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BISMARCK ND
539 PM CDT SAT JUL 4 2020

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

0538 PM     HAIL             ASHLEY                  46.03N 99.38W
07/04/2020  M0.88 INCH       MCINTOSH           ND   LAW ENFORCEMENT

&&

NJH

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