Hail and Damaging Winds in Montana, June 9, 2016

Area Forecast Discussion
National Weather Service GLASGOW MT
148 PM MDT THU JUN 9 2016

.SHORT TERM...for northeast Montana...tonight through Friday...

Late this afternoon hot temperatures are apparent over the lower
yellowstone valley where readings in the mid to upper 90s are
fairly widespread. Further north temps are close to 90 with
additional increases possible. Therefore will leave the heat
advisory out until 7 pm.

An initial push of general thunderstorms pushed through portions
of northeast Montana earlier this morning/early afternoon.
Stronger storms are beginning to develop over central Montana, and
will likely be developing over northeast Montana as well. A quasi-
stationary frontal boundary along with an approaching shortwave
trough in a southwest flow aloft will serve as a focus for
thunderstorm development into the evening hours. Dewpoints in the
mid 50s to mid 60s will provide a good moisture source and
subsequent additional potential energy for severe thunderstorms
through the evening hours. With strong to severe thunderstorms
expected, a severe thunderstorm watch is in effect for all of
northeast Montana until 10pm MDT. Late this evening thunderstorm
activity will largely exit the area...with a few scattered showers
left over the region.

Friday will bring a brief respite as weak ridging builds back in.
Temperatures will remain warm, 80s to low 90s, with just an
outside shot of a stray thunderstorm building into the Little
Rockies or Petroleum county. Gilchrist

.LONG TERM...Fri night through Thu... The extended period as
described below remains largely on track. Changes were made only
for collaboration purposes with the focus being severe weather
potential on Saturday. Given the 12z GFS solution coming in a
little to the south decided to extend pops back in that fashion.
Covering a larger area will be sufficient given some uncertainty
on placement. At this point with lots of instability and low level
moisture along with an approaching shortwave, Saturday promises to
be an active day with scattered showers and thunderstorms
expected. Some storms may contain very large hail and/or damaging
wind. Folks across northeast Montana should have an action plan
ready for when watches and/or warnings become issued. Maliawco

Previous long term discussion...

Synoptic Setup: long range begins with a large area of hot high
pressure building that has been suppressed into the Desert
Southwest and Four Corners. A ridge juts out from this airmass
into the central and northern US Plains. A large trough sets over
the Pacific Northwest and British COlumbia. The clash of these two
systems has generated a large area of southwest flow running from
California through Montana which is providing an express lane of
Pacific moisture and jetstreaks with vorticity spikes over in the
flow zone including northeast Montana. Farther west, another large
trough is moving from the Aleutian Islands into the Gulf of
Alaska.

Saturday night through Monday night: Trough to the west will move
northeastward lifting over Alberta and Saskatchewan. This will
bring some slightly cooler air to the region Saturday night with a
weak surface front. However, once the front exits and washes out
Sunday, the lack of a cooler trough airmass, will also allow the
Desert Southwest Airmass to slowly gain greater influence Monday
through Wednesday raising the heat across the region.

Tuesday onward: The larger trough over the Gulf of Alaska will
drop in over the Pacific Northwest and take the place of the
previous one if it does not move farther south. This will
reorient flow aloft over eastern Montana into a very active south
to southwest pattern again with excess heat also flowing in ahead
of the trough. Models are not sure where or when this large trough
is going break through the heat barrier over the Intermountain
West but the first guesses appear to be around Thursday. This
could easily change with future runs.

&&

.AVIATION...
Scattered showers and thunderstorms will continue this afternoon
and evening with isolated severe thunderstorms capable of
damaging winds and large hail. This weather will present the main
impact to any terminals today. Light southeast winds this morning
will become northwest at 10 to 20 kts with a cold frontal passage
this afternoon. Expect gusty and erratic winds in and near any
thunderstorms. Maliawco

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 7 PM MDT this evening for Dawson...Eastern
Roosevelt...Prairie...Richland...Sheridan...Wibaux.

&&

weather.gov/glasgow

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GLASGOW MT
144 PM MDT THU JUN 9 2016

MTZ016>027-059>062-101000-
CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY-
DANIELS-SHERIDAN-WESTERN ROOSEVELT-PETROLEUM-GARFIELD-MCCONE-
RICHLAND-DAWSON-PRAIRIE-WIBAUX-NORTHERN PHILLIPS-
SOUTHWEST PHILLIPS-NORTHERN VALLEY-EASTERN ROOSEVELT-
144 PM MDT THU JUN 9 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST
MONTANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

A HEAT ADVISORY IS IN EFFECT FOR AREAS ALONG THE NORTH DAKOTA
BORDER AND ALONG THE LOWER MISSOURI RIVER VALLEY THROUGH 7 PM
THIS EVENING.

A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR ALL OF NORTHEAST
MONTANA UNTIL 10 PM TONIGHT. LARGE HAIL AND DAMAGING WINDS ARE
THE MAIN THREATS WITH THUNDERSTORMS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED SATURDAY AFTERNOON AND
EVENING. SOME OF THESE STORMS MAY BECOME SEVERE WITH LARGE HAIL
AND DAMAGING WINDS.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.