Severe Thunderstorm Warning 21, NWS Glasgow, MT

625 
WWUS55 KGGW 292203
SVSGGW

Severe Weather Statement
National Weather Service Glasgow MT
403 PM MDT Mon Jun 29 2020

MTC021-109-292230-
/O.CON.KGGW.SV.W.0021.000000T0000Z-200629T2230Z/
Wibaux MT-Dawson MT-
403 PM MDT Mon Jun 29 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM MDT
FOR CENTRAL WIBAUX AND SOUTHEASTERN DAWSON COUNTIES...

At 403 PM MDT, a severe thunderstorm was located 8 miles southeast of
Intake, or 13 miles east of Glendive, moving north at 45 mph.

HAZARD...Two inch hail and 70 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect 
         considerable tree damage. Wind damage is also likely to 
         mobile homes, roofs, and outbuildings.

Locations impacted include...
Glendive, Intake, Hodges and Stipek. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until midnight MDT for northeastern
Montana.

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4697 10426 4701 10468 4716 10468 4732 10464
      4721 10415 4700 10424
TIME...MOT...LOC 2203Z 185DEG 41KT 4718 10444 

HAIL...2.00IN
WIND...70MPH
 
$$

NWS Glasgow

Area Forecast Discussion
National Weather Service Glasgow MT
324 PM MDT Mon Jun 29 2020

.DISCUSSION...
The upper level low currently over Idaho will begin to open up and
move northward through the area, then re-close over southern
Alberta on Wednesday. Meanwhile, an upper low over northern
British Columbia will drop south into Washington by Wednesday,
being absorbed by the low in Alberta. This low will drift
northward into northern Alberta late in the week, allowing a ridge
to build from the Desert Southwest to the Upper Mississippi
Valley. This in turn will lead to a southwest flow aloft late in
the week, with the peak of the ridging over our area being Friday
through Sunday: when the warmest temperatures are expected.

Short term (tonight through Tuesday night)...
The two main issues in this time frame are the potential for
severe weather and heavy rainfall in the eastern parts of the CWA.
The SPC has a slight risk roughly east of a Navajo to Terry line,
with a marginal risk east of a Glentana to Rock Springs line. The
slight risk area looks reasonable given forecast soundings and the
fact that the sun is currently (as of 3 pm MDT) out over the SPC's
slight risk area, helping to destabilize the atmosphere there. Any
storms that do develop will also have the potential to produce
heavy downpours, given the high values of precipitable water all
across the area and especially there. Gave thought to issuing a
flash flood watch in the far eastern zones, but after some
internal discussion we opted against it due to the fact that the
ground is dry there (but not so dry as to enhance runoff) due to
the D0/D1 drought conditions. Flash flood guidance is in the range
of about an inch per hour and higher to get flash flooding, which
could be hit by an isolated storm but not widespread enough to
warrant a watch.

Shower/storm chances will begin to decrease from west to east
across the area tomorrow, while the east stays wet.

Medium/long term (Wednesday through the weekend)...
As mentioned above, the upper low will move out and we'll be
semi-ridged allowing temperatures to go back up. There will still
be disturbances in the flow that help to trigger some showers and
storms, but they shouldn't be as widespread as what we're
experiencing today.

97

&&

.AVIATION...
FLIGHT CONDITION: VFR/MVFR with occasional IFR.

WINDS: NE-N 10-15 kts today, becoming variable this evening and W
5-10 kts overnight tonight. W-SW winds 5-15 kts expected Tuesday.

SYNOPSIS: Showers and a few thunderstorms will impact the TAF
sites today. Some storms with strong winds and hail are possible
at KSDY & KGDV late this afternoon and this evening, tapering off
to showers during the late evening and overnight hours. Rain will
lower visibilities and ceilings at times to MVFR and occasionally
to IFR through tonight.

97

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

weather.gov/glasgow