Flash Flood Warning 8, NWS Great Falls, MT

886 
WGUS75 KTFX 092351
FFSTFX

Flash Flood Statement
National Weather Service Great Falls MT
551 PM MDT Fri Jun 9 2023

MTC041-051-101-100130-
/O.CON.KTFX.FF.W.0008.000000T0000Z-230610T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hill MT-Liberty MT-Toole MT-
551 PM MDT Fri Jun 9 2023

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM MDT THIS 
EVENING FOR WEST CENTRAL HILL, NORTHERN LIBERTY AND EASTERN TOOLE 
COUNTIES...

At 551 PM MDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Up to 2 inches of rain have fallen. 
Flash flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Whitlash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4896 11133 4897 11117 4896 11106 4890 11078
      4887 11075 4881 11068 4868 11071 4865 11089
      4865 11109 4872 11136

FLASH FLOOD...RADAR INDICATED

$$

AM

547 
WGUS75 KTFX 100120
FFSTFX

Flash Flood Statement
National Weather Service Great Falls MT
720 PM MDT Fri Jun 9 2023

MTC041-051-101-100130-
/O.EXP.KTFX.FF.W.0008.000000T0000Z-230610T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hill MT-Liberty MT-Toole MT-
720 PM MDT Fri Jun 9 2023

...FLASH FLOOD WARNING WILL EXPIRE AT 730 PM MDT THIS EVENING FOR 
WEST CENTRAL HILL, NORTHERN LIBERTY AND EASTERN TOOLE COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

A Flood Watch remains in effect until 600 AM MDT Saturday for 
portions of central and north central Montana.

LAT...LON 4896 11133 4897 11117 4896 11106 4890 11078
      4887 11075 4881 11068 4868 11071 4865 11089
      4865 11109 4872 11136

$$

AM

Area Forecast Discussion
National Weather Service Great Falls MT
201 PM MDT Fri Jun 9 2023

.SYNOPSIS...

Daily rounds of scattered showers and thunderstorms are expected
through the weekend into early next week. The flooding threat is
expected to diminish by the second half of the weekend; however,
Some of the stronger storms will be still capable of producing
localized heavy rainfall. Seasonably mild temperatures are
generally expected for the foreseeable future.

&&

.DISCUSSION...

Showers and some embedded thunderstorms over Central/North-
central MT will continue to lift northward along and north of the
axis of anomalously high PWATS (1 to 1.2 inches) this afternoon
into tonight. The greatest potential for flooding will continue
over the northern/eastern portions of the CWA. So far, impacts
from flooding have been relatively minor and are mostly
concentrated over an area extending from Judith Gap to Lewistown
this afternoon. Flood Advisories have been issued to highlight the
impacts from moderate to heavy rain over saturated soils. The
southwestern portion of the Flood Watch has been trimmed to match
the drier air moving in from the southwest. Great Falls, White
Sulphur Springs, and the Big Belt/Little Belt Mountains are no
longer in the watch. Areas along the Rocky Mountain Front and the
northern portions of North-central MT were left in the watch, but
may be dropped if convection fails to develop this afternoon and
evening.

Another impulse will bring more showers and some thunderstorms
again on Saturday, but there are no plans to extend the Flood
Advisory beyond the 6 am Saturday expiration with the 24 hour
probability for 1 inch or more of rain falling well below 20% for
the remainder of the weekend. However, a moist and unstable air
mass will remain over Central and Southwest Montana through early
next week, resulting in more daily rounds of showers and
thunderstorms.

Deterministic and ensemble guidance continues to bring an upper
level trof through the Northern Rockies Wednesday into Thursday.
This would result in an increased chance for higher surface winds,
a chance for thunderstorms and slightly cooler temperatures. -
RCG

&&

.AVIATION...
1110 AM MDT Fri Jun 9 2023 (09/18Z TAF Period)

Showers persist along the Hi-Line and portions of eastern Central
Montana, mainly impacting the KCTB, KHVR, and KLWT terminals through
the early afternoon. Showers will continue to propagate
southeastward across North-central and Central Montana throughout
the afternoon hours, reducing visibility and cloud ceilings to MVFR
conditions at times. Some IFR conditions are possible for a time in
areas of heavier rainfall. Lowered cloud ceilings will aid in some
mountain obscuration, especially along the Rocky Mountain Front and
Little Belt mountains after 6z Saturday and toward the latter end of
the TAF period. - Pierce

Refer to weather.gov/zlc for more detailed regional aviation weather
and hazard information.

&&

.HYDROLOGY...

A moderate risk (> 40%) for rainfall exceeding flash flood
guidance continues through tonight for the eastern portions of
North Central MT and a slight risk (> 15 %) for locations farther
west. Showers and embedded thunderstorms will be capable of
producing rainfall rates exceeding a half inch per hour at times
in these areas. This rainfall, combined with previous heavy rains,
could result in the potential for flash flood conditions.

The threat for at least marginal flash flood conditions is likely
to continue daily over portions of the CWA through at Tuesday as
periods of scattered showers and thunderstorms continue.

In terms of river flooding, the larger rivers seem to be handling
most of the precipitation, with some rises. There is a small chance
a larger river could go above flood stage for a short time, and
we will continue to monitor this closely.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  57  71  54  75 /  50  70  30  60
CTB  54  70  52  75 /  80  70  20  60
HLN  58  75  56  78 /  50  70  40  80
BZN  50  74  50  75 /  20  60  30  70
WYS  39  70  39  69 /  20  60  20  80
DLN  47  73  50  72 /  10  40  30  70
HVR  58  76  53  80 /  70  50  10  20
LWT  54  66  51  71 /  80  90  30  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late tonight for Bears Paw Mountains and
Southern Blaine-East Glacier Park Region-Eastern Glacier,
Western Toole, and Central Pondera-Eastern Pondera and Eastern
Teton-Eastern Toole and Liberty-Fergus County below 4500ft-Hill
County-Judith Basin County and Judith Gap-Northern Blaine County-
Northern High Plains-Snowy and Judith Mountains-Southern High
Plains-Southern Rocky Mountain Front-Western and Central
Chouteau County.

&&

http://www.weather.gov/greatfalls

Special Weather Statement
National Weather Service Great Falls MT
346 PM MDT Fri Jun 9 2023

MTZ304-305-092215-
Hill County MT-Eastern Toole and Liberty MT-
346 PM MDT Fri Jun 9 2023

...A strong thunderstorm will impact portions of northeastern Liberty
and west central Hill Counties through 415 PM MDT...

At 345 PM MDT, Doppler radar was tracking a strong thunderstorm 13
miles north of Inverness, or 23 miles northeast of Chester, moving
northwest at 40 mph.

HAZARD...Half inch hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to outdoor objects is possible.

This storm will remain over mainly rural areas of northeastern
Liberty and west central Hill Counties.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4875 11047 4865 11057 4882 11119 4900 11103
      4900 11089
TIME...MOT...LOC 2145Z 121DEG 33KT 4875 11061

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...<30 MPH

AM