Severe Thunderstorm Warning 28, NWS Glasgow, MT

Area Forecast Discussion
National Weather Service GLASGOW MT
251 PM MDT FRI JUN 10 2016

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

...A threat for severe storms exists tonight across portions of
northeast Montana. A more widespread severe weather potential may
unfold for Saturday afternoon and evening...

A continued threat for severe thunderstorms exist for portions of
northeast montana this evening and tonight with the primary
threats being large hail and damaging winds.

A large upper trough across the Pacific Northwest continues to
drive diffluent southwest flow aloft across Montana. Meanwhile,
surface high pressure south of the region is helping to maintain
light southeast flow. Over time, this will increase low level
moisture. Already dew points are climbing into the 50s in areas
south of the Missouri River. SSEO maximum updrafts look to track
along or to the south of the Missouri River. Though anyone in
northeast Montana has some risk of a severe storm tonight, the
better potential will be here. This will be similar in nature, if
a little north, that what just occurred on Thursday.

Saturday will feature much more in the way of instability and low
level moisture, all while a cold front approaches from the west.
CAPE may exceed 4000 J/KG in some locations with 40-50 kts of 0-6
km bulk vertical shear, which may increase further at night.
Storms will be much more widespread by Saturday afternoon and
capable of very large hail, damaging winds, and brief heavy
rainfall. Initial supercells may organize into linear features as
they progress late in the evening and as shear profiles increase
even further with strengthening LLJ. Anyone with plans or
interests in the area, in particular near the North Dakota Border,
should pay close attention to later forecasts as well as for any
watches and warnings that may be issued. Remember, when thunder
roars, go indoors! Now is the time to have a plan of action in
place for when severe weather strikes.

Cooler and drier weather is expected on Sunday with high pressure
moving into the region. Maliawco

.LONG TERM...Sun night through Fri...

Only minor adjustments made to the going forecast for next week.
Overall pattern with southwest flow aloft is favorable for
thunderstorms although models are somewhat dry for the period.
Question mark will be forcing with shortwaves lifting through the
flow and persistence of a closed low over the upper Midwest may
push their track into western Montana. Kept the focus for pops
over the northwestern zones for most of the period. Ebert

Previous long term discussion...The extended period begins Sunday
night with west to southwest flow aloft for the region. The
pattern evolves into pure southwest flow for the remainder of the
extended term. This is being caused by an upper low dropping into
the Northeastern Pacific off Vancouver Island and remains there
from Tuesday lasting into Saturday. The main problem will be
timing different shortwave through the flow to adjust thunderstorm
chances for the region.

The main impact periods look to be Monday and Tuesday for now with
general thunderstorms possible each day and night within this type
of upper pattern. Monday and Tuesday pose enough instability to be
monitored for enhanced convective wording in future forecast
updates as we near those periods. Otherwise the general slight
chance to chance thunderstorms mainly in the afternoon and evening
hours looks to be a good bet.

The guidance is fairly agreeable on the upper low forcing the area
into pure southwest flow aloft and do differ some on features with
timing and placement. Confidence is fairly good for the period of
mid June will isolated to scattered Thunderstorms and seasonal
temperatures.

Proton

&&

.AVIATION...
VFR conditions will prevail this evening, however, scattered showers
and thunderstorms may bring temporary MVFR CIGS and VSBYS. Some of
the storms may be severe with damaging winds and large hail. Light
southeast winds will continue this evening, though winds will be
gusty and erratic in and near storms. Maliawco

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory from midnight tonight to 4 PM MDT Saturday
For Fort Peck Lake for Central and Southern Valley...Garfield...
McCone.

&&

weather.gov/glasgow

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GLASGOW MT
329 AM MDT FRI JUN 10 2016

MTZ016>027-059>062-110930-
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-
329 AM MDT FRI JUN 10 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST
MONTANA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS ARE POSSIBLE TONIGHT ACROSS NORTHEAST MONTANA. SOME
STORMS MAY BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS.

A LAKE WIND ADVISORY IS IN EFFECT FOR THE EAST HALF OF FORT PECK
LAKE TONIGHT AND SATURDAY FOR EAST WINDS 15 TO 25 MPH.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED SATURDAY AFTERNOON AND
EVENING. SOME OF THESE STORMS WILL BECOME SEVERE WITH LARGE HAIL
AND DAMAGING WINDS. LOCALLY HEAVY RAIN IS ALSO POSSIBLE.

.SPOTTER INFORMATION STATEMENT...

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