A passing upper level trough produced northwesterly breezy conditions and gusts up to 60 mph across Washington during the afternoon of May 1, 2021.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. 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.
A passing upper level trough produced northwesterly breezy conditions and gusts up to 60 mph across Washington during the afternoon of May 1, 2021.
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 May 1, 9:54 AM PST, 3 hours 6 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
1054 AM PDT Sat May 1 2021
Updated aviation discussion below...
.MORNING UPDATE...
Current satellite and radar trends depict a broad band of mainly
light showers extending from Central Oregon northeast into the
mountains of northeast Oregon and far southeast Washington.
Occasional moderate shower activity has been observed from time
within modest convective elements. This activity is expected to
continue to drift south and east in association with a weak upper
wave. In addition, modest instability in a narrow corridor ahead
of ongoing shower activity may lead to a stray thunderstorm mainly
across far southern Grant county, however, no strong or severe
thunderstorm activity is expected. Thereafter, breezy to locally
windy conditions expected to develop across parts of the area.
This is well supported by recent high resolution ensemble forecast
system runs depicting wind gusts of 35 to 50 mph across the
Columbia Basin, eastern gorge, and the Kittitas Valley.
The existing forecast is largely on track, but made some minor
modifications to PoPs and added in slight chance thunder. Also
made some minor changes to winds and gusts to better time peak
winds this afternoon. Otherwise, the forecast is in good shape.
79/Austin
&&
AVIATION...18Z TAFs...A band of showers continues from portions of
Central Oregon into eastern Oregon. This is resulting in MVFR/IFR
ceilings at KRDM/KBDN and KPDT/KALW. This will improve later this
afternoon as this activity shift east. Breezy west winds 15 to 25
knots expected to develop from 20z to 03z, with gusts of 35 t0 45
knots possible. Strongest winds will be in the Kittitas Valley and
Columbia Gorge, mainly affecting KDLS. Winds to decrease after 06z
with increasing cloudiness overnight. Low ceilings may affect
KRDM/KBDN overnight, but confidence is too low to mention in TAFs at
this time.
&&
.PREV DISCUSSION... /issued 442 AM PDT Sat May 1 2021/
SHORT TERM...
Today through Monday night...Latest radar imagery showed an area
of rain extending from southwest to northeast from southwestern
Oregon across the Cascades into Central Oregon and into portions
of the Columbia Basin. Model guidance initially did not handle
this precipitation well, but has since been doing better with its
forecast. The guidance has the precipitation moving southeast with
time over the course of the morning and into the afternoon hours
and that it will have mostly exited the region to the east by
evening. Overall QPF amounts will be light, but there could be
amounts around 0.25 inches in the Ochocos.
The rain is associated with a weak upper level trough that is
moving onshore, a very decent area of shortwave energy and a
surface frontal boundary. As the trough moves through, winds will
increase, mainly this afternoon. Winds will become gusty and wind
advisories have been issued for the Kittitas Valley and Eastern
Gorge. Outside of these areas, most locations will see 25 to 35
mph wind gusts.
The trough will move to the east tonight and allow for an upper
ridge to build back into the Pacific Northwest. The ridge will be
over the area through Monday and dry weather is expected. Some
rain associated with an upper level disturbance will move onshore
of the Washington coast Monday afternoon. Some showers for the
Cascades are possible during this time. As the shortwave moves
south into Oregon, additional showers, mainly over the Blues and
Wallowas are possible by Monday night, with little, if any
precipitation expected elsewhere.
High temperatures today will be a bit cooler than on Friday, with
most locations in the mid to upper 60s, although the Basin will
still be in the mid 70s. Sunday will be a few degrees cooler, with
low to mid 60s and the Basin near 70. Highs on Monday will be
similar to Sunday. Overnight lows will be in the 30s and 40s
tonight and mainly in the 30s Sunday night.
LONG TERM...
Tuesday through Saturday...Deterministic and ensemble
members in good agreement through the middle of next week and the
weekend, however, guidance diverges on timing of weather system
Thursday. Overall, there will a period dry weather in the midweek,
which will give way to unsettled weather Thursday into the
weekend.
Tuesday, shortwave trough providing lingering showers over Wallowa
county will push east as an upper level ridge of high pressure
builds into the region. The forecast area will see a return to dry
conditions while temperatures will warm into the upper 70s and mid
80s by Thursday afternoon. Locally breezy conditions will develop
Tuesday and Wednesday afternoon, however, winds will turn easterly
Wednesday as lower sets up west of the Cascades. Meanwhile, models
are consistent in showing a deep low dropping south then east out
of the Gulf of Alaska through Wednesday. By Thursday, the upper
level ridge will push east out of the region as the deep low
approaches the PacNW, placing the region in a southwest flow
aloft. Overall, deterministic and ensemble members are in good
agreement with progression of synoptic pattern into the weekend,
however, there are timing differences in the arrival and passage
of a leading surface cold front Thursday. In general, ensemble
mean members quickly move the cold front over the Cascades and
into the forecast area Thursday morning. That said, investigating
the ensemble cluster analysis indicates that there is disagreement
within the individual members of the ensembles. As for the
deterministic members and the NBM, the frontal passage does not
occur until later Thursday. For now, have gone with the late
Thursday time frame of the frontal passage. Ahead of and behind
frontal passage, breezy westerly winds will develop across the
forecast area while showers are expected mainly in the mountain
zones. Friday and Saturday, upper low will move into and across
the PacNW with showers mainly in the mountains and central OR
while breezy westerly winds continue. Cooler temperatures will
also return Friday and into the weekend as the upper low pushes a
cooler airmass into the region. Lawhorn/82
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 69 42 64 38 / 60 0 0 0
ALW 72 46 67 44 / 50 0 0 0
PSC 76 43 71 41 / 0 0 0 0
YKM 73 38 71 41 / 0 0 0 0
HRI 75 43 70 40 / 30 0 0 0
ELN 63 39 66 40 / 0 0 0 0
RDM 65 35 61 28 / 80 0 0 0
LGD 66 41 60 35 / 60 0 0 0
GCD 64 41 58 35 / 80 0 0 0
DLS 69 45 69 44 / 0 0 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from noon today to 9 PM PDT this evening for
ORZ041.
WA...Wind Advisory from noon today to 9 PM PDT this evening for
WAZ024-026.
&&
SHORT TERM...79
LONG TERM....82
AVIATION...82The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
A non-thunderstorm wind gust of 60mph was measured by the ASOS KELN in Ellensburg, WA at 2:01 pm PDT.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2021Every state in 2021This day in weather historyWarnings in Washington, May 2021
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: 968094.