Alert archive / Idaho / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 2, NWS Missoula, MT
NWS Missoula, MT issued this severe thunderstorm warning at May 20, 1998, 3:56 PM PDT for Idaho County, Idaho. It was in force for 44 min. 1 report came from inside the area while it was in force.
The area
The counties it named, with what was reported inside it.
The facts
- Issued
- May 20, 1998, 3:56 PM PDT (22:56 UTC)
- Expired
- May 20, 1998, 4:40 PM PDT
- In force
- 44 min
- Issued by
- NWS Missoula, MT
- Area
- Whole counties
County Idaho County, ID
The radar
The Missoula radar (KMSX), 175 km from the middle of the area, began a volume at 22:56 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 20, 4:15 PM PDT | Hail 0.75 | Fenn, ID | Hail to 3/4 inch was reported by severe weather spotter in Fenn. |
NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.
The nearest sounding before it
Spokane, WA (KOTX), launched 12:00Z, 10.9 hours before the alert went out and 218 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1760 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km storm-relative helicity
- 36 m²/s²
- 0-3 km storm-relative helicity
- 67 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KMSO 202301 RRA SVRMSO IDC049-202340- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE MISSOULA MT 356 PM PDT (456 PM MDT) WED MAY 20 1998 THE NATIONAL WEATHER SERVICE HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... NORTHWESTERN IDAHO COUNTY IN CENTRAL IDAHO * UNTIL 440 PM PDT (540 PM MDT) * 345 PM PDT SEVERE THUNDERSTORM INDICATED A SEVERE THUNDERSTORMS 5 MILES WEST AND ALSO 15 MILES NORTHWEST OF GRANGEVILLE...BY NATIONAL WEATHER SERVICE DOPPLER RADAR... MOVING NORTH-NORTHWEST AT 20 MPH. * SEVERE THUNDERSTORM WILL BE NEAR... NEAR FERDINAND AT 530 PDT SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55 MPH... DESTRUCTIVE HAIL...DEADLY LIGHTVNING...AND VERY HEAVY RAIN. FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO AREAS WHERE WATER COVERS THE ROAD.
What forecasters said that day
The local office's own words before this severe thunderstorm warning 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 severe thunderstorm warning went out at May 20, 12:45 PM PDT, 3 hours 11 minutes earlier.
Area forecast discussion, May 20, 12:45 PM PDT, 3 hours 11 minutes before
WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION NATIONAL WEATHER SERVICE MISSOULA MT 145 PM MDT WED MAY 20 1998 ETA SEEMS TO HAVE GOOD HANDLE ON SHORTWAVE ROTATING AROUND CUTOFF LOW OVER SW OREGON. NOT MUCH DYNAMICS FOR CWA TODAY BUT AIRMASS IS FAIRLY UNSTABLE AND SOME CONVECTION ALREADY DEVELOPING OVER SOUTHERN EDGE OF DISTRICT. MOISTURE MOVING NORTH FROM 4 CORNERS AREA COMES TOGETHER WITH SHORTWAVE MOVING NORTH AS CUTOFF PROGRESSES EASTWARD DURING THE DAY THURSDAY FOR LIKELY POPS THURSDAY CONTINUING INTO THURSDAY NIGHT. ETA BEGINS DRYING THINGS OUT BY 12Z FRIDAY AND EXPECT THIS TREND TO CONTINUE SO LOWER POPS FRIDAY. TEMPS WILL SHOW COOLING TREND AS LOW APPROACHES LOWERING HEIGHTS/THICKNESS. HOADLEY ...FORECASTS BELOW ARE PRELIMINARY AND SUBJECT TO CHANGE... LIB .. 049/069 051/066 ... 405675 FCA WW 047/068 049/065 045 405675 POL .. 052/069 053/066 ... 405665 MSO WW 047/067 049/064 045 404665 HMM .. 048/068 050/065 ... 404665 BTM .. 041/065 039/062 ... 403765 S80 .. 044/067 042/064 ... 404664 P69 .. 049/065 047/062 ... 404664 SMN .. 043/068 041/065 ... 404654
Nearby
Severe Thunderstorm Warnings in Idaho, 1998Every severe thunderstorm warning 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.