Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Great Falls, MT

July 9, 2021Lewis and Clark County, Montana

NWS Great Falls, MT issued this special weather statement at Jul 9, 2021, 12:22 PM MDT for Lewis and Clark County, Montana. It was in force for 23 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 9, 2021, 12:22 PM MDT (18:22 UTC)
Expired: Jul 9, 2021, 12:45 PM MDT
In force: 23 min
Issued by: NWS Great Falls, MT

County Lewis and Clark County, MT

The radar

The Great Falls radar (KTFX), 83 km from the middle of the area, began a volume at 18:22 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 6.4 hours before the alert went out and 137 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 34 J/kg
Mixed-layer CIN: -410 J/kg
Mixed-layer LCL: 1971 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: -47 m²/s²
0-3 km storm-relative helicity: -52 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.1

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Great Falls, MT wrote its last area forecast discussion before this special weather statement went out at Jul 9, 7:29 AM MDT, 4 hours 53 minutes earlier.

Area forecast discussion, Jul 9, 7:29 AM MDT, 4 hours 53 minutes before

Area Forecast Discussion
National Weather Service Great Falls MT
729 AM MDT Fri Jul 9 2021

.UPDATE...

Updated PoPs to help make them a little less precise to make sure
all areas that could see a shower or thunderstorm actually
reflects that in the grids and point-and-click forecasts given the
15 percent threshold needed to trigger the mention of such. Also
raised winds for Sunday across the region, which may require
evaluation as to whether a Fire Weather Watch is needed for some
fire districts.

&&

.SYNOPSIS...
A weather disturbance will move from west to east across the
region today, resulting in a few thunderstorms. Some of the storms
could be strong once again in the Lewistown area. Otherwise, warm
afternoon temperatures are expected today, however expect hot
temperatures over the weekend, along with mostly dry conditions.

&&

.AVIATION...
400 AM MDT Fri Jul 9 2021 (09/12Z TAF period)

VFR conditions currently over the region will give way to some MVFR
conditions in/near thunderstorms by late this morning and during
the afternoon hours today. The thunderstorms will generally move
from west to east through the region today. Any storms should be
short at the terminals, generally lasting less than 30 minutes.
Also, expect a surface wind shift to the north for a few hours.
Otherwise, VFR conditions return across the region this evening.
Mountains passes could be obscured at times by storms. Also, smoke
could reduce distant visibility at times for locations along the
divide, mostly this morning. Brusda

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

&&

.PREV DISCUSSION...
/ISSUED 359 AM MDT Fri Jul 9 2021/
Today thru Sunday...The main concern today is an upper level
disturbance moving from west to east across the region.
Thunderstorms could develop this morning over North Central MT,
with a chance for a few strong storms, mostly east/south of
Lewistown this afternoon. There is a low probability that a
stronger storm could develop in the Havre area. The storms exit
the area early this evening, with mostly dry/hot temperatures
expected over the region this weekend. Additionally, areas of
smoke could affect locations near the divide this morning.

Monday thru Friday...Overall, expect summer like temperatures for
all of next week. The main concern is the potential for an upper
level disturbance to move through the region on Tuesday. The GFS
has higher probabilities for wetter conditions over Central MT.
This solution seems to have fairly low probability, thus rather a
scattered shower seems more likely. Thus pops are only slight
chance to chance for now. As we move towards next weekend, an
upper level ridge will try to rebuild over the area, resulting in
the warm/hot temperatures along with little/no precipitation.
Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  85  52  97  54 /  30   0   0   0
CTB  83  51  93  53 /  40   0   0   0
HLN  89  56  98  60 /  40   0   0   0
BZN  88  49  94  53 /  30  10   0   0
WYS  83  37  86  41 /   0   0   0   0
DLN  87  49  92  53 /   0   0   0   0
HVR  86  56  94  59 /  30  20   0   0
LWT  80  52  90  58 /  60  20   0   0

&&

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

http://www.weather.gov/greatfalls

In the hours before

Local storm report, Jul 9, 7:29 AM MDT, 4 hours 53 minutes before

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Local storm report, Jul 9, 7:37 AM MDT, 4 hours 45 minutes before

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Special weather statement, Jul 9, 8:19 AM MDT, 4 hours 3 minutes before

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Special weather statement, Jul 9, 8:41 AM MDT, 3 hours 41 minutes before

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Special weather statement, Jul 9, 8:53 AM MDT, 3 hours 29 minutes before

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Special weather statement, Jul 9, 12:22 PM MDT, 0 minutes before

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The office that day

Everything else NWS Great Falls, MT issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 9, 8:19 AM MDT	Special Weather Statement	TFX	Teton	41 min
Jul 9, 8:41 AM MDT	Special Weather Statement	TFX	Teton	49 min
Jul 9, 8:53 AM MDT	Special Weather Statement	TFX	Teton	52 min
Jul 9, 12:34 PM MDT	Special Weather Statement	TFX	Lewis and Clark	41 min
Jul 9, 12:52 PM MDT	Special Weather Statement	TFX	Lewis and Clark	23 min
Jul 9, 1:03 PM MDT	Special Weather Statement	TFX	Meagher	27 min
Jul 9, 1:12 PM MDT	Special Weather Statement	TFX	Lewis and Clark	33 min
Jul 9, 1:31 PM MDT	Special Weather Statement	TFX	Blaine	29 min
Jul 9, 1:42 PM MDT	Special Weather Statement	TFX	Broadwater	33 min
Jul 9, 1:55 PM MDT	Special Weather Statement	TFX	Blaine	35 min
Jul 9, 1:59 PM MDT	Special Weather Statement	TFX	Cascade	31 min
Jul 9, 2:05 PM MDT	Special Weather Statement	TFX	Glacier	25 min
Jul 9, 2:16 PM MDT	Special Weather Statement	TFX	Pondera	29 min
Jul 9, 2:21 PM MDT	Special Weather Statement	TFX	Broadwater	24 min
Jul 9, 2:28 PM MDT	Special Weather Statement	TFX	Blaine	32 min
Jul 9, 2:44 PM MDT	Special Weather Statement	TFX	Pondera	31 min
Jul 9, 2:46 PM MDT	Special Weather Statement	TFX	Blaine	29 min
Jul 9, 2:51 PM MDT	Special Weather Statement	TFX	Glacier	24 min
Jul 9, 3:11 PM MDT	Special Weather Statement	TFX	Blaine, Hill	34 min
Jul 9, 3:17 PM MDT	Special Weather Statement	TFX	Pondera	28 min
Jul 9, 3:18 PM MDT	Special Weather Statement	TFX	Glacier	27 min
Jul 9, 3:40 PM MDT	Special Weather Statement	TFX	Cascade	35 min
Jul 9, 3:48 PM MDT	Special Weather Statement	TFX	Pondera	27 min
Jul 9, 3:52 PM MDT	Special Weather Statement	TFX	Blaine, Hill	38 min
Jul 9, 4:14 PM MDT	Special Weather Statement	TFX	Pondera	31 min
Jul 9, 4:20 PM MDT	Special Weather Statement	TFX	Blaine, Hill	40 min
Jul 9, 4:59 PM MDT	Special Weather Statement	TFX	Chouteau	46 min
Jul 9, 5:43 PM MDT	Special Weather Statement	TFX		32 min

Nearby

Special Weather Statements in Montana, 2021 Every special weather statement in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.