Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Great Falls, MT

June 10, 2021Cascade County, Montana

NWS Great Falls, MT issued this special weather statement at Jun 10, 2021, 5:33 PM MDT for Cascade County, Montana. It was in force for 27 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
Jun 10, 2021, 5:33 PM MDT (23:33 UTC)
Expired
Jun 10, 2021, 6:00 PM MDT
In force
27 min
Issued by
NWS Great Falls, MT

County Cascade County, MT

The radar

The Great Falls radar (KTFX), 31 km from the middle of the area, began a volume at 23:34 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, 11.6 hours before the alert went out and 28 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-pSkew-T log-p diagram, Great_falls, MT at 12:00Z on 2021-06-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great_falls, MT at 12:00Z on 2021-06-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 166 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1207 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
166 m²/s²
0-3 km storm-relative helicity
685 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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 Jun 10, 1:14 PM MDT, 4 hours 19 minutes earlier.

Area forecast discussion, Jun 10, 1:14 PM MDT, 4 hours 19 minutes before
Area Forecast Discussion
National Weather Service Great Falls MT
114 PM MDT Thu Jun 10 2021

.SYNOPSIS...

Scattered showers and thunderstorms this afternoon will move
away to the east overnight. Temperatures remain cool on Friday
before a significant warming trend begins this weekend. Expect
widespread 90s at least next Monday and Tuesday.

&&

.DISCUSSION...

A potent upper level trough and its attendant surface front is
crossing the Continental Divide this afternoon. Observations
reveal a line of showers and thunderstorms developing over
Southwest Montana. This activity will continue to spread further
east through the evening as the trough lifts from Southwest toward
Northeast. A cool and stable airmass remains in place over North-
central Montana. Only scattered light rain showers would be
expected here until the front passes through and increasing
westerly downslope winds develop. Isolated stronger thunderstorms
are possible further east, where stability and shear profiles are
more favorable for possibly severe convection. The main concern
from any severe thunderstorms (eastern Fergus and Blaine counties)
will be gusty winds and large hail. The passing cold front will
lower snow levels to around 6000 feet, so some light snow
accumulation may be possible where precipitation lingers
overnight. Furthermore, frost is likely tonight for some of the
higher elevation Southwest valleys. Skies clear out on Friday to
start the beginning of a warming trend. PN

Saturday through next Thursday...A broad ridge of high pressure
builds across the area this weekend into at least early next week,
bringing dry conditions and significant warming. Widespread 80s
are expected by Sunday, with a few 90s possible. The peak of the
next heat wave looks to occur Monday and Tuesday Tuesday, with
afternoon temperatures in the 90s for much of the CWA, and a few
100s can't be ruled out. There is fairly good agreement that on
Wednesday a Pacific cool front will move through the region,
resulting in increased winds developing. Between the anticipated
dry nature of this front and the antecedent hot and dry weather,
fire weather concerns would be on the rise. This 'cool' front may
bring some relief from the heat for Wednesday and next Thursday,
but the degree of any cool-off remains uncertain as there is
disagreement among the deterministic models and increasing spread
in ensemble probabilities. -Kredensor

&&

.AVIATION...
1130 AM MDT Thursday Jun 10 2021 (10/18Z TAF period)

Low stratus remains over KHVR/KLWT producing IFR/MVFR conditions.
These clouds are expected to thin and mix out through late
afternoon. A cold front advancing across the Continental Divide is
helping to generate a line of thundershowers. Expect increasing
coverage of thunderstorms, likely impacting KHLN/KBZN/KEKS/KWYS
(southwest Montana terminals) around 00-03Z. Skies gradually clear
overnight, with prevailing VFR conditions on Friday.

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  40  70  45  78 /  30   0   0   0
CTB  39  66  41  70 /  30   0   0   0
HLN  40  73  48  82 /  40   0   0   0
BZN  35  71  43  83 /  70   0   0   0
WYS  27  61  33  75 /  70   0   0   0
DLN  32  67  43  80 /  50   0   0   0
HVR  44  72  46  80 /  30   0   0   0
LWT  39  69  44  79 /  50   0   0   0

&&

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

http://www.weather.gov/greatfalls

In the hours before

Special weather statement, Jun 10, 4:56 PM MDT, 37 minutes before
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Local storm report, Jun 10, 5:19 PM MDT, 14 minutes before
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Local storm report, Jun 10, 5:20 PM MDT, 13 minutes before
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Local storm report, Jun 10, 5:21 PM MDT, 12 minutes before
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Local storm report, Jun 10, 5:22 PM MDT, 11 minutes before
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Special weather statement, Jun 10, 5:33 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.

IssuedProductOfficeCountiesLasted
Jun 9, 6:18 PM MDTSevere Thunderstorm WarningTFXBlaine42 min
Jun 9, 6:55 PM MDTSevere Thunderstorm WarningTFXBlaine35 min
Jun 9, 7:08 PM MDTSpecial Weather StatementTFXFergus22 min
Jun 9, 7:19 PM MDTSpecial Weather StatementTFXTeton56 min
Jun 9, 7:26 PM MDTSpecial Weather StatementTFXFergus34 min
Jun 9, 7:28 PM MDTSpecial Weather StatementTFXJudith Basin32 min
Jun 9, 7:36 PM MDTSpecial Weather StatementTFXFergus24 min
Jun 9, 7:53 PM MDTSevere Thunderstorm WarningTFXChouteau, Fergus37 min
Jun 9, 7:57 PM MDTSpecial Weather StatementTFXHill33 min
Jun 9, 8:04 PM MDTSpecial Weather StatementTFXJudith Basin26 min
Jun 9, 8:19 PM MDTSpecial Weather StatementTFXTeton26 min
Jun 9, 8:28 PM MDTSevere Thunderstorm WarningTFXChouteau, Judith Basin32 min
Jun 9, 8:31 PM MDTSpecial Weather StatementTFXChouteau29 min
Jun 9, 8:42 PM MDTSevere Thunderstorm WarningTFXBlaine, Fergus33 min
Jun 9, 8:45 PM MDTSpecial Weather StatementTFXPetroleum30 min
Jun 9, 8:48 PM MDTSpecial Weather StatementTFXHill27 min
Jun 9, 8:57 PM MDTSpecial Weather StatementTFXBlaine18 min
Jun 9, 9:04 PM MDTSevere Thunderstorm WarningTFXChouteau, Hill26 min
Jun 9, 9:09 PM MDTSevere Thunderstorm WarningTFXBlaine, Fergus21 min
Jun 9, 9:18 PM MDTSpecial Weather StatementTFXToole42 min
Jun 9, 9:26 PM MDTSpecial Weather StatementTFXBlaine49 min
Jun 9, 9:30 PM MDTSevere Thunderstorm WarningTFXBlaine45 min
Jun 9, 9:37 PM MDTSpecial Weather StatementTFXBlaine23 min
Jun 9, 9:38 PM MDTSpecial Weather StatementTFXFergus37 min
Jun 9, 9:38 PM MDTSevere Thunderstorm WarningTFXBlaine40 min
Jun 9, 9:51 PM MDTSpecial Weather StatementTFXBlaine24 min
Jun 9, 10:17 PM MDTSpecial Weather StatementTFXBlaine28 min
Jun 9, 10:32 PM MDTSpecial Weather StatementTFXFergus43 min
Jun 9, 10:48 PM MDTSevere Thunderstorm WarningTFXBlaine42 min
Jun 9, 11:34 PM MDTSpecial Weather StatementTFXBlaine, Fergus, Hill116 min
Jun 10, 2:11 AM MDTSpecial Weather StatementTFXBlaine34 min
Jun 10, 2:53 PM MDTSpecial Weather StatementTFXFergus37 min
Jun 10, 3:08 PM MDTSevere Thunderstorm WarningTFXFergus52 min
Jun 10, 3:53 PM MDTSpecial Weather StatementTFXFergus37 min
Jun 10, 4:22 PM MDTSpecial Weather StatementTFXCascade23 min
Jun 10, 4:56 PM MDTSpecial Weather StatementTFXCascade34 min

Nearby

Special Weather Statements in Montana, 2021Every 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.