Alert archive / Oregon / Flash Flood Warnings in 2021

Flash Flood Warning 1, NWS Pendleton, OR

July 31, 2021Grant County, Oregon

NWS Pendleton, OR issued this flash flood warning at Jul 31, 2021, 4:44 PM PDT for Grant County, Oregon. It was in force for 108 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 31, 2021, 4:44 PM PDT (23:44 UTC)
Expired
Jul 31, 2021, 6:32 PM PDT
In force
108 min
Issued by
NWS Pendleton, OR
Area
Storm-based polygon
Flood severity
None

County Grant County, OR

The radar

The Pendleton radar (KPDT), 108 km from the middle of the area, began a volume at 23:45 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 12:00Z, 11.7 hours before the alert went out and 217 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, Boise Airport, ID at 12:00Z on 2021-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 172 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Boise Airport, ID at 12:00Z on 2021-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -6 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
172 J/kg
Mixed-layer CIN
-246 J/kg
Mixed-layer LCL
1811 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
-6 m²/s²
0-3 km storm-relative helicity
60 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

853 
WGUS56 KPDT 312344
FFWPDT
ORC023-010145-
/O.NEW.KPDT.FF.W.0001.210731T2344Z-210801T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pendleton OR
444 PM PDT Sat Jul 31 2021

The National Weather Service in Pendleton has issued a

* Flash Flood Warning for...
  Eastern Grant County in central Oregon...

* Until 645 PM PDT.

* At 444 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Additional rainfall amounts of 1 to 2 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  mainly rural areas of Eastern Grant County

Anthony Lakes Mountain Resort

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

&&

LAT...LON 4485 11830 4484 11832 4483 11831 4482 11831
      4481 11830 4480 11830 4478 11829 4477 11828
      4477 11829 4475 11829 4475 11830 4474 11832
      4474 11835 4476 11836 4478 11836 4479 11835
      4480 11835 4482 11835 4483 11836

FLASH FLOOD...RADAR INDICATED

$$

RSC
1 follow-up statement
302 
WGUS76 KPDT 010132
FFSPDT

Flash Flood Statement
National Weather Service Pendleton OR
632 PM PDT Sat Jul 31 2021

ORC023-010142-
/O.CAN.KPDT.FF.W.0001.000000T0000Z-210801T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Grant OR-
632 PM PDT Sat Jul 31 2021

...FLASH FLOOD WARNING IS CANCELLED FOR EASTERN GRANT COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

A Flash Flood Watch remains in effect until 1100 PM PDT Sunday for 
portions of Oregon and southeast Washington.

LAT...LON 4485 11830 4484 11832 4483 11831 4482 11831
      4481 11830 4480 11830 4478 11829 4477 11828
      4477 11829 4475 11829 4475 11830 4474 11832
      4474 11835 4476 11836 4478 11836 4479 11835
      4480 11835 4482 11835 4483 11836

$$

RSC

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 31, 2:49 PM PDTFlash Flood WatchPDTCrook, Deschutes, Gilliam, Grant, Jefferson, Morrow and 5 more30 hr

Nearby

Flash Flood Warnings in Oregon, 2021Every flash flood warning in 2021

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.