Alert archive / Montana / Flood Watches in 2018

Flood Watch 8, NWS Missoula, MT

May 23, 20185 counties in Montana

NWS Missoula, MT issued this flood watch at May 23, 2018, 9:34 AM MDT for 5 counties in Montana. It was in force for 4 days.

The area

The counties it named.

The facts

Issued
May 23, 2018, 9:34 AM MDT (15:34 UTC)
Expired
May 27, 2018, 11:04 AM MDT
In force
4 days
Issued by
NWS Missoula, MT
Area
Storm-based polygon
Flood severity
None

Counties Flathead County, MT, Lake County, MT, Missoula County, MT, Ravalli County, MT, Sanders County, MT

The radar

The Missoula radar (KMSX), 40 km from the middle of the area, began a volume at 15:38 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

Spokane, WA (KOTX), launched 12:00Z, 3.6 hours before the alert went out and 165 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, Spokane, WA at 12:00Z on 2018-05-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 78 joules per kilogram.LCLLFCEL10008507005003002001001 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, Spokane, WA at 12:00Z on 2018-05-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 43 square meters per square second.193958Sfc1 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
78 J/kg
Mixed-layer CIN
-165 J/kg
Mixed-layer LCL
1873 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
43 m²/s²
0-3 km storm-relative helicity
71 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Missoula, MT wrote its last area forecast discussion before this flood watch went out at May 23, 4:17 AM MDT, 5 hours 17 minutes earlier.

Area forecast discussion, May 23, 4:17 AM MDT, 5 hours 17 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
May 23, 9:26 AM MDTAreal Flood WarningMSOSanders8 days
May 23, 9:45 AM MDTAreal Flood WarningMSOMineral, Missoula5 days
May 23, 4:29 PM MDTSpecial Weather StatementMSORavalli31 min
May 22, 6:23 PM MDTSpecial Weather StatementMSOIdaho37 min
May 23, 4:27 PM MDTSpecial Weather StatementMSOLewis18 min

Nearby

Flood Watches in Montana, 2018Every flood watch in 2018

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.