Alert archive / Oregon / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 13, NWS Pendleton, OR

May 4, 1998Umatilla County, Oregon

NWS Pendleton, OR issued this severe thunderstorm warning at May 4, 1998, 7:06 PM PDT for Umatilla County, Oregon. It was in force for 44 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
May 4, 1998, 7:06 PM PDT (02:06 UTC)
Expired
May 4, 1998, 7:50 PM PDT
In force
44 min
Issued by
NWS Pendleton, OR
Area
Whole counties

County Umatilla County, OR

The radar

The Pendleton radar (KPDT), 14 km from the middle of the area, began a volume at 02:10 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 00:00Z, 2.1 hours before the alert went out and 295 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 00:00Z on 1998-05-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 51 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 00:00Z on 1998-05-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 27 square meters per square second.1939Sfc1 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
51 J/kg
Mixed-layer CIN
-64 J/kg
Mixed-layer LCL
2177 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
27 m²/s²
0-3 km storm-relative helicity
38 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.

484 
WUUS1 KPDT 050207 RRA
SVRPDT
ORC059-050250-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PENDLETON OR
706 PM PDT MON MAY 4 1998

THE NATIONAL WEATHER SERVICE IN PENDLETON HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EASTERN UMATILLA COUNTY IN NORTHEASTERN OREGON

* UNTIL 750 PM PDT

* AT 700 PM PDT... DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 29
  MILES EAST OF PENDLETON OR 9 MILES EAST OF MEACHAM MOVING
  NORTHWEST AT 15 MPH.  THE SEVERE THUNDERSTORM WARNING FOR WESTERN
  UNION COUNTY HAS EXPIRED.

* THIS STORM CAN BE EXPECTED IN THE VICINITY OF...
MEACHAM                      AROUND 715 PM PDT


SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55
MPH...DESTRUCTIVE HAIL...DEADLY LIGHTNING...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
DONT DRIVE INTO AREAS WHERE WATER COVERS THE ROAD.

SMITH

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 Pendleton, OR wrote its last area forecast discussion before this severe thunderstorm warning went out at May 4, 2:00 PM PDT, 5 hours 6 minutes earlier.

Area forecast discussion, May 4, 2:00 PM PDT, 5 hours 6 minutes before
NORTHEAST OREGON/SOUTHEAST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
200 PM PDT MON MAY 04 1998

KPDT RADAR AND VISIBLE LOOPS SHOW BUILDUPS FORMING ALONG THE
SOUTHERN BLUE MOUNTAINS.  ALTHOUGH NO LIGHTNING STRIKES OBSERVED AT
THIS HOUR IN NE OREGON...BELIEVE CONVECTIVE SHOWERS AND
THUNDERSTORMS WILL SOON TAKE PLACE.  QUESTION REMAINS IS HOW FAR
NORTH TO EXPECT THE CONVECTIVE ACTIVITY.  HIGH PRESSURE AND AN
EASTERLY FLOW ALOFT WILL KEEP THE WASHINGTON PORTION OF OUR COUNTY
WARNING AREA DRY AND STABLE.  EASTERLY FLOW ALOFT WILL ALSO KEEP
THE SHORTWAVE AND MOISTURE MAINLY OVER SOUTHERN OREGON.  YET...WILL
NOT RULE OUT THUNDERSTORMS ALONG THE FOOTHILLS OF BLUE MTNS
TONIGHT.  WILL MENTION SLIGHT CHANCE FOR WALLA WALLA.

THE PERSISTANT CUTOFF LOW WILL FINALLY SHIFT EASTWARD AND FILL OVER
THE NEXT SEVERAL DAYS.  AN UPPER LEVEL TROF OFF THE ALEUTIAN
ISLANDS WILL DROP SOUTHEASTWARD AND KICK THE CUTOFF LOW INLAND.
MORE WRAP-AROUND MOISTURE WILL PROVIDE SHOWERS AND THUNDERSTORMS
TUESDAY YET SHOULD TAPER OFF BY WEDNESDAY.  MRF AND NOGAPS SHOW
SPLIT FLOW OFF THE EASTERN PACIFIC WITH THE NEXT SHORTWAVE AT END
OF EXTENDED PERIOD.   SMITH

PDT 3221  ALW 2110  PSC 0000  YKM 0000

.KPDT-88D...VCP31/CSR21.

.KPDT...SEE PDXFLSPDT STATEMENT NO. 10

The office that day

Everything else NWS Pendleton, OR issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 4, 5:31 PM PDTSevere Thunderstorm WarningPDTCrook, Deschutes49 min
May 4, 6:15 PM PDTSevere Thunderstorm WarningPDTUmatilla, Union50 min

Nearby

Severe Thunderstorm Warnings in Oregon, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.