Alert archive / Oregon / Flash Flood Warnings in 1998

Flash Flood Warning 3, NWS Pendleton, OR

May 6, 1998Grant County, Umatilla County, Oregon

NWS Pendleton, OR issued this flash flood warning at May 6, 1998, 5:30 PM PDT for Grant County, Umatilla County, Oregon. It was in force for 65 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 6, 1998, 5:30 PM PDT (00:30 UTC)
Expired: May 6, 1998, 6:35 PM PDT
In force: 65 min
Issued by: NWS Pendleton, OR
Area: Whole counties

Counties Grant County, OR, Umatilla County, OR

The radar

The Pendleton radar (KPDT), 72 km from the middle of the area, began a volume at 00:34 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

Boise Airport, ID (KBOI), launched 00:00Z, 0.5 hours before the alert went out and 268 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: 620 J/kg
Mixed-layer CIN: -27 J/kg
Mixed-layer LCL: 1764 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: -22 m²/s²
0-3 km storm-relative helicity: 24 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.

000 
TTAA00 KPDT 070031
FFWPDT
ORC023-059-070120-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PENDLETON OR
530 PM PDT WED MAY 6 1998

THE NATIONAL WEATHER SERVICE IN PENDLETON HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHERN UMATILLA COUNTY IN NORTHEASTERN OREGON
  NORTHERN GRANT COUNTY IN EAST CENTRAL OREGON
  
* UNTIL 635 PM PDT

* AT 515 PM PDT... NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
A THUNDERSTORM WITH VERY HEAVY RAIN OVER CREEKS FEEDING INTO THE
UPPER REACHES OF THE NORTH FORK OF THE JOHN DAY RIVER.

* A THUNDERSTORM BETWEEN 300 PM AND 430 PM PRODUCED HEAVY RAIN ALONG
  THE NORTH FORK OF THE JOHN DAY RIVER. RUNOFF FROM THAT STORM AND
  FROM OTHER THUNDERSTORMS MOVING OVER THE UPPER REACHES OF THE
  NORTH FORK OF THE JOHN DAY RIVER WILL KEEP FLASH FLOOD CONDITIONS
  ALONG THE RIVER.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY.  THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YO>UR CAR TO
CROSS SAFELY.  VEHICLES CAUGHT IN RISING WATER SHOULD BE
ABANDONED QUICKLY.  MOVE TO HIGHER GROUND.

What forecasters said that day

The local office's own words before this flash flood 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 flash flood warning went out at May 6, 2:30 PM PDT, 3 hours earlier.

Area forecast discussion, May 6, 2:30 PM PDT, 3 hours before

NORTHEAST OREGON/SOUTHEAST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
230 PM PDT WED MAY 06 1998 ...corrected ykm pop for 4th period

TSTMS HAVE DEVELOPED OVR MTNS IN MOISTURE THAT HAS FLOWED OVER AND
AROUND THE RIDGE DOMINATING THE NORTHWEST. STORMS APPEAR TO BE
GARDEN VARIETY...HOWEVER THEY ARE MOVING SLOWLY AND WILL HAVE TO
WATCH FOR PROBLEMS WITH LOCALLY HEAVY RAIN.

AS RIDGE CONTINUES TO BUILD INTO OREGON BELIEVE TSTMS LESS LIKELY
OVR MTNS TMRW. CONSENSUS IN COORD CALL WAS THAT AVN WAS TOO FAST
WITH NEXT SYSTEM...AND ETA LOOKED MORE REASONABLE. EXTRAPOLATING
THE ETA OUT PAST 48 HRS...TROF MOVES INTO ZFA FRIDAY NIGHT OR SAT
BRINGING BREEZY CONDITIONS AND A C|HANCE OF SHOWERS FOR THE WEEKEND.
STONESIFER

PDT 0001  ALW 0001  PSC 0001  YKM 0000

.KPDT-88D...VCP21/CSR21.

.KPDT...SEE PDXFLSPDT STATEMENT NO. 20

Nearby

Flash Flood Warnings in Oregon, 1998 Every flash flood 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.