Alert archive / Idaho / Severe Thunderstorm Watches in 1998

Severe Thunderstorm Watch 252

April 23, 19989 counties in Idaho; 6 counties in Montana

The Storm Prediction Center issued this severe thunderstorm watch at Apr 23, 1998, 3:00 PM PDT for 9 counties in Idaho; 6 counties in Montana. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Apr 23, 1998, 3:00 PM PDT (22:00 UTC)
Expired: Apr 23, 1998, 9:00 PM PDT
In force: 6 hr
Issued by: the Storm Prediction Center

Counties Benewah County, ID, Bonner County, ID, Boundary County, ID, Clearwater County, ID, Kootenai County, ID, Latah County, ID, Lewis County, ID, Nez Perce County, ID, Shoshone County, ID, Flathead County, MT, Lake County, MT, Lincoln County, MT, Mineral County, MT, Missoula County, MT, Sanders County, MT

The radar

The Missoula radar (KMSX), 122 km from the middle of the area, began a volume at 22:01 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.

Warnings issued inside it

3 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Apr 23, 4:48 PM PDT	Severe Thunderstorm Warning	OTX	Bonner	47 min
Apr 23, 5:47 PM PDT	Severe Thunderstorm Warning	OTX	Boundary	43 min
Apr 23, 6:28 PM PDT	Severe Thunderstorm Warning	OTX	Boundary	62 min

The nearest sounding before it

Spokane, WA (KOTX), launched 12:00Z, 10.0 hours before the alert went out and 109 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: 1 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1569 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 27 m²/s²
0-3 km storm-relative helicity: 91 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

474 
WWUS9 KMKC 232131
SEL2  
MKC WW 232131
MTZ000-IDZ000-240400-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 252
STORM PREDICTION CENTER NORMAN OK
331 PM MDT THU APR 23 1998

THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

   NORTHWEST MONTANA                            
   NORTHERN IDAHO                              

EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 400 PM UNTIL
1000 PM MDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 80 STATUTE MILES
EAST AND WEST OF A LINE FROM 75 MILES NORTHWEST OF KALISPELL
MONTANA TO 75 MILES SOUTHWEST OF MISSOULA MONTANA.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. 
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

OTHER WATCH INFORMATION...  CONTINUE...WW 250...WW 251...

DISCUSSION...THUNDERSTORMS OVER SE WA/NE ORE SHOULD SPREAD INTO NRN
ID/NW MT DURING THE NEXT FEW HOURS. DAMAGING WINDS AND HAIL ARE
POSSIBLE GIVEN STEEP LAPSE RATES AND HIGH DEWPOINT DEPRESSIONS NEAR
THE SURFACE.


AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450.  MEAN STORM
MOTION VECTOR 24030.


...VESCIO

490,1133 460,1133 460,1165 490,1171

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 23, 11:30 AM PDT	Severe Thunderstorm Watch	SPC	Kootenai, Latah, Nez Perce, Payette, Washington	6 hr
Apr 23, 1:00 PM PDT	Severe Thunderstorm Watch	SPC	Ada, Adams, Blaine, Boise, Camas, Canyon and 13 more	6 hr

Nearby

Severe Thunderstorm Watches in Idaho, 1998 Severe Thunderstorm Watches in Montana, 1998 Every severe thunderstorm watch in 1998

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.