An upper level ridge provided very hot conditions across the region, while in the mid-levels moisture was able to skirt the boundary of the ridge from central OR to central WA. The increased uplift from hot temperatures and the moisture resulted in a very slow moving thunderstorm that developed over Klickitat county and produced large hail and heavy downpours.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS PDT wrote it up.
An upper level ridge provided very hot conditions across the region, while in the mid-levels moisture was able to skirt the boundary of the ridge from central OR to central WA. The increased uplift from hot temperatures and the moisture resulted in a very slow moving thunderstorm that developed over Klickitat county and produced large hail and heavy downpours.
The local office's own words before the first event, 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 the first event at Jul 28, 2:52 PM PST, 1 hour 54 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
352 PM PDT Thu Jul 28 2022
.Updated aviation discussion
.SHORT TERM...Tonight through Saturday...The short term remains
characterized by very hot and dry conditions, with a few isolated
storms for Central Oregon through the start of the weekend.
Temperatures are expected to remain fairly similar over the next
few days, with widespread highs in the 100-110 range for most
lower elevation locations, and highs of 90-100 for the mountains
with high confidence (90%). High pressure ridging is not expected
to begin deteriorate until later Sunday as a low approaches the
PacNW coastline. Overnight lows of 60's to 70's will be warm for
this time of year, continuing the increased HeatRisk for all areas
of the CWA.
Plumes of mid level moisture will continue to swing along the
periphery of the ridge, creating a daily risk of isolated
thunderstorms that will mostly manifest in Central Oregon. A few
small storms are currently noted in the region, with incredibly
limited lightning activity and little to no precipitation expected
to make it to the ground as it evaporates through the mid and
lower levels. This should mostly preclude a widespread lightning
risk.
Sensible fire weather concerns should also be mostly limited for
the region over the next few days. Relative humidities will be
critical, but overall flow is not expected to be strong enough to
present winds that will create a Red Flag threat. A few breezes
may be possible daily across the Kittitas Valley that will
coincide with the lowest RH's, but this region should be
incredibly limited in both scope and timing as RH's begin to climb
just after winds begin to breeze and allow for enough recovery to
occur. Still, this will present at least an elevated concern that
should be watched. Goatley/87
.LONG TERM...Sunday through Thursday... The long term period will
see the persistent ridge of high pressure responsible for the nearly
week of abnormally hot temperatures finally come to an end. However,
the transition out of the ridge brings a chance for more active
weather for the early part of the week, likely in the form of
afternoon thunderstorms for central Oregon and parts of the Oregon
Cascades through the eastern Mountains. Excessive heat highlights
remain in place through Sunday before temperatures finally trend
cooler Monday onward, albeit with increasing uncertainty in the
overall pattern.
Models are in fairly good agreement regarding the upper-level
pattern to start the extended period on Sunday, depicting a cut-off
low off the southern Oregon Coast and a ridge of high pressure
firmly planted overhead. The persistent ridge likely facilitates one
more day of widespread triple digit temperatures and accompanying
high to very high heat risk values, especially around the Columbia
Basin. Both latest GEFS and ECMWF ensembles support higher
temperatures compared to previous runs as well with the vast
majority of members holding onto 28-32 degree 850mb temperatures
over the CWA. Beyond just the heat, a wave of monsoonal moisture
situated above 700mb will work its way into the region Sunday as
well, likely due to the increasing influence of the cut-off low
offshore. Daytime heating and the resulting instability in
combination with the aforementioned mid-level moisture may spark
thunderstorm development during the afternoon and evening hours from
central Oregon into the central Blue Mtns. That said, there are some
discrepancies as to the exact coverage and timing of convection due
to variations in the moisture field aloft. Regardless, it is
appearing more likely parts of the region will see some convective
activity late Sunday into Sunday evening.
Monday into the middle of the week models appear split as to the
exact progression of the cut-off low situated off the southern
Oregon Coast, having ramification on thunderstorm chances, gap
winds, and fire weather concerns. Cluster analysis reveals two
primary scenarios. The deterministic GFS and GEFS ensemble favor a
significantly more progressive solution, bringing the area of low
pressure through the Pacific Northwest on Monday in response to a
passing wave to our north followed by weak troughing and modest
westerly flow the rest of the week. This would keep the thunderstorm
chances limited to mainly Sunday/Monday over the mountains but
produce breezy conditions Monday onward which may increase fire
concerns briefly before humidity recovers. Temperatures stay cooler
in this scenario as well. On the other hand the deterministic ECMWF,
ECMWF ensemble, and to some extent the CMC keep the cut-off low
churning offshore into the middle of the week before finally moving
it inland Thursday. The resulting persistent south to southwest flow
would greatly increase the chance for afternoon thunderstorms over
the mountain areas Monday through Wednesday. With all of this in
mind expect a transition to an active pattern but confidence
regarding the duration and timing of impactful conditions remain low
at this time beyond Sunday evening. 99
&&
.AVIATION...00Z TAFs...VFR conditions will prevail during the next
24 hours with just a few mid and/or high clouds. Winds may be
locally breezy at times this evening at KDLS, KPDT, KRDM, and KBDN,
otherwise winds will be light and under 10 Kts. 88
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 68 108 68 107 / 0 0 0 0
ALW 72 109 72 108 / 0 0 0 0
PSC 72 110 70 110 / 0 0 0 0
YKM 69 110 66 108 / 10 0 0 0
HRI 71 111 70 111 / 0 0 0 0
ELN 68 107 66 106 / 0 0 0 0
RDM 61 106 63 106 / 10 0 0 0
LGD 64 102 63 103 / 0 0 0 0
GCD 64 103 65 104 / 10 0 0 0
DLS 74 110 73 110 / 0 0 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Excessive Heat Warning until 11 PM PDT Sunday for ORZ041-044-505-
507-508-510-511.
Heat Advisory until 11 PM PDT Sunday for ORZ049-050-502-503-506-
509.
WA...Excessive Heat Warning until 11 PM PDT Sunday for WAZ024-026>029-
521.
Heat Advisory until 11 PM PDT Sunday for WAZ030.
Excessive Heat Warning until 11 PM PDT Saturday for WAZ520.
&&
SHORT TERM...87
LONG TERM....99
AVIATION...88The Pendleton radar (KPDT), 123 km away, was scanning. The volume nearest the first event began at 00:45 UTC.
1 hail. Local standard time, as filed.
A member of the public reported quarter to golf ball size hail stones from a thunderstorm that was nearly stationary over the Bickleton area.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2022Every state in 2022This day in weather historyWarnings in Washington, July 2022
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1049373.