An upper level trough combined with increasing mid level moisture and surface instability led to the development of severe thunderstorms across portions of northeast Oregon.
Every event with a place to put it. Tap one for its entry below.
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 trough combined with increasing mid level moisture and surface instability led to the development of severe thunderstorms across portions of northeast Oregon.
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 Aug 5, 3:21 AM PST, 1 hour 29 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
421 AM PDT Mon Aug 5 2024
.SHORT TERM...
Today through Wednesday night...
Latest radar imagery showed isolated to scattered showers and
thunderstorms extending from the Washington Cascade crest
northeastward to the Columbia Basin. Model guidance has been
handling these storms poorly, but the NAM, the one model with
perhaps the best indication of them, does have these storms
dissipating later this morning.
Lightning has been low overall, but persistent. Nevertheless, a
red flag warning has been issued for these areas through the
morning hours.
A second round of thunderstorms is expected later this morning and
into the afternoon, perhaps extending into the evening over
predominantly the eastern Oregon mountains and extending into
southeast Washington. The model guidance has been handling these
thunderstorms well. As a result, a second red flag warning has
been issued for this area through the afternoon hours.
An upper level trough will move on shore tonight into Wednesday.
dry weather is expected with the trough passage though there could
be some locally gusty winds later Tuesday into Wednesday. Wind
gusts look to generally be in the 20 to 25 mph range.
At this time, probabilities of winds >=39 mph are all generally
40% or less, except up toward the Kittitas Valley. Winds will have
to be watched for possible fire weather headlines as we head into
Tuesday night/Wednesday morning but any gusty winds will increase
the potential for fire spread.
Otherwise, once we get past today, a period of more quiet weather
looks to be in store. High temperatures will generally be 5 to 10
degrees above normal through the period, with today being the
warmest of the next 3.
.LONG TERM... Thursday through Monday... The
long-term period is characterized by a trough moving over the
PacNW on Thursday, pushing the ridge eastward. Northwesterly flow
will continue prevailing across the region through Monday.
There are slight chances (15-30%) of showery thunderstorms
developing for Friday night and Saturday late morning into
afternoon. Confidence level is low (<20%) for precip with models
showing limited of moisture due to dry conditions. Though, this
instability will remain posing a threat to any ongoing large fires
within the region. High confidence (>70%)in the soundings still
indicating high lapse rates through the forecast period. Winds will
be around 20 mph or less with the weakened surface pressure
gradients.
Temperatures will remain in the 90s in the lower elevations with
relative humidity above critical levels. Area smoke/haze might stick
around due to nearby wildfires, but low confidence in duration and
extent to impact visibility and air quality. Feaster/97
&&
.AVIATION...
12Z TAFS...VFR conditions will continue throughout this period
with isolated thunderstorms possibly KDLS/KALW/KPSC. As these
isolated storms persist across the valley zones and upper portions
of Columbia Basin, not expecting any other sites to be impacted.
Winds will mostly be less than 12 kts. However, winds gusts will
develop around 25kts at sites KDLS/KRDM/KBDN with sustained winds
at 12-17kts this afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 95 63 91 56 / 20 0 0 0
ALW 99 66 95 61 / 10 0 0 0
PSC 100 68 97 63 / 20 0 0 0
YKM 98 59 95 59 / 20 0 0 0
HRI 101 66 96 61 / 20 0 0 0
ELN 96 62 92 62 / 0 0 0 0
RDM 93 55 90 49 / 0 10 0 0
LGD 98 60 91 54 / 30 10 0 0
GCD 99 59 93 54 / 10 0 0 0
DLS 96 62 91 62 / 20 0 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 10 AM PDT this morning for ORZ639.
Red Flag Warning from 10 AM this morning to 5 PM PDT this
afternoon for ORZ643-645.
WA...Red Flag Warning until 10 AM PDT this morning for WAZ691-694.
Red Flag Warning from 10 AM this morning to 5 PM PDT this
afternoon for WAZ692-693.
&&
SHORT TERM...77
LONG TERM....97
AVIATION...97The Pendleton radar (KPDT), 22 km away, was scanning. The volume nearest the first event began at 12:51 UTC.
3 hail. Local standard time, as filed.
A social media report indicated hail up to the size of 0.88 inches fell in Milton-Freewater between 0600 to 0620 PDT.
A social media report from Cove, Oregon indicated a thunderstorm produced hail stones to the size of 0.75 inches.
A social media report from Lostine, Oregon indicated that hail stones up to 1.25 inches in size fell around 1627 PDT. A trained spotter 1 mile west northwest of Lostine reported hail stones to the size of 1 inch around 1628 PDT.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2024Every state in 2024This day in weather historyWarnings in Oregon, August 2024
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: 1214901, 1214902, 1214904.