Alert archive / Idaho / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 21, NWS Missoula, MT

August 7, 1999Clearwater County, Idaho

NWS Missoula, MT issued this severe thunderstorm warning at Aug 7, 1999, 3:32 PM PDT for Clearwater County, Idaho. It was in force for 58 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued
Aug 7, 1999, 3:32 PM PDT (22:32 UTC)
Expired
Aug 7, 1999, 4:30 PM PDT
In force
58 min
Issued by
NWS Missoula, MT
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Clearwater County, ID

The radar

The Missoula radar (KMSX), 117 km from the middle of the area, began a volume at 22:32 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 7, 1:00 PM PDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Spokane, WA (KOTX), launched 12:00Z, 10.5 hours before the alert went out and 131 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 1999-08-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 207 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 1999-08-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 102 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
207 J/kg
Mixed-layer CIN
-109 J/kg
Mixed-layer LCL
1178 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
102 m²/s²
0-3 km storm-relative helicity
196 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.7

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KMSO 072234 RRA
SVRMSO
IDC035-072330-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MISSOULA MT
332 PM PDT SAT AUG 7 1999

THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EASTERN CLEARWATER COUNTY IN NORTHERN IDAHO

* UNTIL 430 PM PDT

* AT 332 PM PDT...RADAR INDICATED A SEVERE THUNDERSTORM 9 MILES EAST
  OF PIERCE...OR 31 MILES EAST OF OROFINO...MOVING NORTHEAST AT 25
  MPH.

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND AND HAIL ALONG WITH
FREQUENT LIGHTNING AND VERY HEAVY RAIN. FOR YOUR PROTECTION...STAY
INDOORS AWAY FROM WINDOWS.

IF YOU ARE CAUGHT OUTSIDE...MOVE TO A STURDY SHELTER OR WELL
PROTECTED AREA.


LAT...LON 4654 11573 4645 11551 4691 11502 4711 11527

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 7, 2:36 PM PDTSevere Thunderstorm WarningMSOIdaho54 min

Nearby

Severe Thunderstorm Warnings in Idaho, 1999Every severe thunderstorm warning in 1999

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.