Special Weather Statement, NWS Great Falls, MT

Area Forecast Discussion
National Weather Service Great Falls MT
550 PM MDT SUN AUG 7 2016

...Update to Aviation...

.DISCUSSION...
Tonight through Tuesday...An unstable southwesterly flow aloft
will reside over the region tonight through Monday. A strong upper
level disturbance will push northeastward through the region this
evening. Numerous thunderstorms will accompany this disturbance
with isolated severe storms. The main threat from any severe storm
will be strong wind gusts...but an isolated large hail report is
also possible. The bulk of the stronger storms will diminish by
9 PM. Another round of thunderstorms will affect portions of the
region on Mon afternoon/evening. This disturbance will not be as
strong as the one day...but an isolated severe thunderstorm can
not be ruled out for tomorrow. On Tuesday an upper level
disturbance will move towards the Glacier Park region...bringing
another chance for widespread thunderstorms across the
region...with North Central MT likely being the most affected area.
Afternoon temperatures for Mon/Tue will not be as hot as they have
been...but still generally average between the mid 70s and mid
80s. Brusda

TUESDAY NIGHT THROUGH SUNDAY...Medium range forecast models continue
to be in good agreement with the solution during this period, and
they are even a bit faster with the exit of the upper level low
pressure trough. The trough is now forecast to move northeast from
the Idaho Panhandle Tuesday evening to southwest Saskatchewan by
early Wednesday evening, which is about 12 hours sooner than last
night's model runs. As a result, the greatest chance for continuing
showers and thunderstorms remains during Tuesday evening, with a
fairly rapidly decreasing chance after that. The northwest flow in
the wake of the trough will keep a slight chance of showers and
thunderstorms over the forecast area mainly through Wednesday night.
As a high pressure ridge builds into the western United States
through Saturday, the only chance for an isolated afternoon/evening
shower or thunderstorm will remain over the mountains. However,
another large upper level trough will dig off the Pacific coast into
Sunday. The resulting southwest flow aloft may bring isolated
showers and thunderstorms to the forecast area, but there is a
chance that the ridge will remain in place, which would keep the
area dry. Regardless, the exit of the trough and the introduction of
the upper ridge will help warm temperatures from 5 to 10 degrees
below normal on Wednesday to a few degrees above normal by Sunday.
Coulston

&&

.AVIATION...
Updated 2350z.
Southwest flow aloft continues overnight and through the day on
Monday. Disturbance currently over central Montana will continue to
generate scattered to numerous showers and thunderstorms through
late evening with light rain showers lingering after midnight.
Monday morning will start off mostly sunny with isolated/scattered
thunderstorms developing over southwest Montana after 20Z. VFR
conditions will prevail except for local IFR visibility in heavy
rain associated with storms. mpj

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  50  82  50  80 /  60  20  20  60
CTB  51  79  48  75 /  70  10  30  60
HLN  51  82  52  80 /  60  40  30  40
BZN  47  84  46  85 /  40  20  10  20
WEY  38  74  40  74 /  20  10  10  10
DLN  45  81  45  80 /  10  20  10  20
HVR  59  82  53  82 /  70  10  30  60
LWT  54  80  53  81 /  70  20  30  40

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.

&&

weather.gov/greatfalls

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
538 PM MDT SUN AUG 07 2016

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

0535 PM     HAIL             1 NW TOWNSEND           46.33N 111.54W
08/07/2016  E0.70 INCH       BROADWATER         MT   TRAINED SPOTTER

            DIME SIZE HAIL FALLING IN THE TOWNSEND AREA.

&&

BRUSDA

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
552 PM MDT SUN AUG 07 2016

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

0547 PM     HAIL             TOWNSEND                46.32N 111.52W
08/07/2016  M1.25 INCH       BROADWATER         MT   PUBLIC

            STILL HAILING AT TIME OF CALL.

&&

MARTIN

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
558 PM MDT SUN AUG 07 2016

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

0555 PM     TSTM WND GST     11 E TOWNSEND           46.33N 111.28W
08/07/2016  M52 MPH          BROADWATER         MT   TRAINED SPOTTER

            SPOTTER REPORTS DIME TO QUARTER SIZED HAIL

0555 PM     HAIL             11 E TOWNSEND           46.33N 111.28W
08/07/2016  M1.00 INCH       BROADWATER         MT   TRAINED SPOTTER

            SPOTTER REPORTS DIME TO QUARTER SIZED HAIL

&&

MPJ

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
608 PM MDT SUN AUG 07 2016

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

0515 PM     TSTM WND GST     8 W TOWNSEND            46.31N 111.70W
08/07/2016  M62 MPH          BROADWATER         MT   MESONET

            62 MPH WIND GUST AT THE ELKHORN RAWS LOCATION. TIME OF
            EVENT IS ESTIMATED.

&&

BRUSDA

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
616 PM MDT SUN AUG 07 2016

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

0600 PM     HAIL             5 SW WINDHAM            47.04N 110.22W
08/07/2016  M1.00 INCH       JUDITH BASIN       MT   TRAINED SPOTTER

            HAIL RANGED FROM PEA SIZED TO LARGER THAN A QUARTER

&&

MPJ

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
625 PM MDT SUN AUG 7 2016

MTZ053-054-080115-
MEAGHER MT-BROADWATER MT-
625 PM MDT SUN AUG 7 2016

...MINOR URBAN FLOODING IN THE TOWNSEND AREA...

HEAVY RAIN HAS CAUSED SOME MINOR URBAN FLOODING IN THE CITY OF
TOWNSEND.

EMERGENCY MANAGERS HAVE REPORTED WATER A FEW INCHES DEEP ON THE MAIN
HIGHWAYS IN TOWNSEND.

THE WATER SHOULD RECEDED IN BY 7 PM AS THE STORMS HAVE EXITED THE
REGION.

REMINDER...DO NOT DRIVE THROUGH ANY FLOOD ROADWAYS. WAIT UNTIL THE
WATER RECEDES OR FIND AN ALTERNATE ROUTE.

LOCATIONS IMPACTED INCLUDE...
TOWNSEND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORRENTIAL RAINFALL HAS OCCURRED WITH THIS STORM...AND HAS LEAD TO
LOCALIZED FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

&&

LAT...LON 4613 11155 4645 11166 4673 11098 4635 11088
TIME...MOT...LOC 0022Z 231DEG 20KT 4632 11149

BRUSDA