The environment across southeast California on August 25th was primed for strong to severe thunderstorms with very moist and unstable conditions in place. The synoptic pattern featured a subtropical ridge of high pressure centered over northern New Mexico, while a Pacific trough to the west promoted upper level divergence over the region.
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 PSR wrote it up.
The environment across southeast California on August 25th was primed for strong to severe thunderstorms with very moist and unstable conditions in place. The synoptic pattern featured a subtropical ridge of high pressure centered over northern New Mexico, while a Pacific trough to the west promoted upper level divergence over the region. These synoptic features also allowed for southerly moisture advection with PWATs climbing upwards of 1.8-2.0 inches. The broad ascent over the region combined with abundant moisture, MLCAPE values in excess of 1,000 to 2,000 J/kg, and DCAPE values in excess of 1,000 J/kg provided an environment conducive to strong to severe thunderstorms capable of producing damaging winds and flash flooding. Daytime heating allowed for continued destabilization with thunderstorms initiating midday across portions of Imperial County near the international border. These thunderstorms became strong to severe through the afternoon, producing numerous instances of wind damage as well as flash flooding, primarily across the Imperial Valley. The most significant flash flooding occurred along Highway 86 near Highway 78 when approximately 200 motorists became stranded in floodwaters. After being hit by damaging thunderstorms on both August 24th and 25th, the Imperial Irrigation District (IID) reported 311 downed power poles with damage estimates for the utility company upwards of 9 to 12 million dollars. Several schools across the Imperial Valley were closed on the 26th after sustaining damage from this event. No fatalities were reported during this event.
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 Phoenix, AZ wrote its last area forecast discussion before the first event at Aug 25, 9:17 AM PST, 2 hours 33 minutes earlier. Its key messages:
Area Forecast Discussion
National Weather Service Phoenix AZ
1017 AM MST Mon Aug 25 2025
.UPDATE...Updated 18z Aviation Discussion.
&&
.KEY MESSAGES...
- A Flood Watch has been issued for much of southwest Arizona and
southeast California for this afternoon and evening. Widespread
showers and thunderstorms will be capable of producing heavy
rainfall localized flooding.
- Showers and thunderstorms are likely over much of the area today
and possibly again on Tuesday. Gusty winds, blowing dust, heavy
rainfall, and localized flooding will all be possible,
especially through this evening.
- Temperatures will cool off over the next couple of days,
dropping to below normal starting Tuesday.
&&
.SHORT TERM /TODAY THROUGH TUESDAY/...
The main forecast concern over the next day or two will be the
potential for heavy rainfall and localized flash flooding given
the strong moisture advection which continues over much of the
region and increased forcing from a Pacific trough coming in from
the west. In addition to the heavy rainfall potential, guidance is
suggesting we may see a few strong to severe wind gusts along
with the potential for strong outflow winds and blowing dust
focused across south-central and southern Arizona.
The synoptic picture over the past couple of days has slowly
changed with the subtropical high centered just to our northeast
weakening while an upper level trough is starting to dig along and
just off the California coast. This is leading to increased
southeasterly flow into the region pulling up good moisture,
pushing PWATs currently to between 1.3-1.6" across the lower
deserts. Over the next 12 hours or so, moisture advection will
continue bumping PWATs more into a 1.5-1.8" range while mixing
ratios rise to a respectable 10-12 g/kg.
Isolated showers and thunderstorms are already developing over
portions of the area, specifically Phoenix and southern Yuma
County. As moisture continues to improve and difluence aloft
increases from the incoming trough by this afternoon, we are
likely to see clusters of showers and thunderstorms to form. Hi-
res CAMs seem to be all over the place as far as placement of
convection later today, but there at least seems to be an overlap
across southeast California and southwest Arizona. This area
should also have the highest moisture and instability, along with
the potential for some training of convective cells. Given the
good moisture and expected instability, it seems fairly likely
some areas will see heavy rainfall and the potential for localized
flooding focused more across southeast California and southwest
Arizona. We have lofted a Flood Watch for a good portion of this
area from early afternoon through mid evening with rainfall
amounts of 1-2" possible within this area.
From Phoenix and areas to the east of Phoenix, moisture will be a
bit more limited, but still fairly good considering what we have
had lately. Instability should also be lower than the western
deserts, but DCAPEs should be higher promoting better chances for
strong outflows. CAMs have been quite uncertain with the potential
shower and thunderstorm coverage, but trends have mostly agreed
on some sort of complex of showers and storms coming out of Tucson
reaching the Phoenix area late in the afternoon and early
evening. This will likely promote some blowing dust across south-
central Arizona, particularly to the south of Phoenix. We also
can't rule out some localized heavy rainfall and minor flooding,
but the chances seem to be too low to include in the Flood Watch.
By late this evening into tonight, guidance generally agrees on a
diminishing threat for shower and thunderstorm activity. Forecast
uncertainty increases further for Tuesday as we are likely to be
under a scenario where we have worked over the atmosphere a good
deal today leaving less instability for Tuesday. There is also
differences in the amount of moisture available for Tuesday with
the GEFS indicating some drying already occurring while the EPS
keeps the 1.5-1.7" PWATs in place. NBM PoPs also seem way out of
whack for Tuesday providing higher chances on Tuesday versus
today. We have lowered PoPs Tuesday to mostly show 30-50% chances
across the lower deserts to 50-70% over the eastern Arizona higher
terrain. Tuesday may end up playing out well for those areas that
do not receive much convection today, specifically from Phoenix
and areas to the east of Phoenix. We also can't rule out a threat
for heavy rainfall and localized flooding on Tuesday focused more
over the eastern portion of the region.
Temperatures today will drop from what we saw over the weekend,
but daytime highs today are likely to still reach to within a
degree or two of normals. The increased moisture and rain cooled
air should bring down temperatures further for Tuesday with highs
anywhere from the mid 90s to around 100 degrees.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
By Wednesday, the influences of the subtropical high will be much
less as it shifts its center over the Southern Plains. At the same
time, the Pacific trough will nudge into at least western
portions of our region leading to lower heights and turning our
flow out of the southwest. This will bring in a good amount of
drier air Wednesday into Thursday, eventually scouring out much of
our low level moisture by Friday. However, the lingering moisture
on Wednesday should still be enough to allow for some isolated
shower and thunderstorm activity likely focused over higher
terrain areas. As the dry air really settles in by Thursday, we
should expect only very minimal rain chances across the eastern
Arizona high terrain. This westerly flow dry pattern is likely to
continue through the upcoming weekend keeping much if not all of
our area dry.
Temperatures should continue to run slightly below normal for
Wednesday and Thursday before some gradual warming pushes highs
back into the normal range of 102-105 degrees by Friday.
Additional warming is favored over the weekend as the subtropical
high somewhat nudges back into our region. The NBM suggests
daytime highs warming back to between 104-108 degree range for
the weekend.
&&
.AVIATION...Updated at 1720Z.
South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Confidence continues to increase for impacts from thunderstorms
later this afternoon into the evening at valley terminals. A
complex of thunderstorms are expected to develop across southern
AZ this afternoon and lift north across the valley by early
evening. These storms will push out a strong outflow from the
south with a general timing of the intial gusty wind shift
expected between 23z-01z. Blowing dust is anticipated with this
outflow due to the favorable SSE direction reducing surface and
slatwise visibilities. This entire complex of storms will likely
(40-60%) shift into the valley. Have added tempo group for
thunderstorms at all terminals, generally in the 01z-05z
timeframe. Some showers will linger into overnight with lingering
sct/bkn cloud cover.
Southeast California/Southwest Arizona including KIPL and KBLH:
SHRA/TSRA with gusty winds will be the primary hazard to
operations through tonight under periods of mid/high cigs above 8K
ft AGL. Confidence is fair that another round of TSRA similar to
yesterday will develop this afternoon south and west of KIPL.
Gusty winds with blowing dust and locally heavy rainfall are
possible before lifting away from the area in the evening, mainly
in the 22-01z timeframe.
&&
.FIRE WEATHER...
Abundant moisture and periods of showers and thunderstorms are
expected early this week. The best rainfall chances today are
likely to be focused across the western districts before shifting
over the eastern districts on Tuesday. Strong gusty winds, heavy
rainfall and localized flooding will be possible, especially
today. Elevated humidities will lead to MinRHs between 25-40%
today and Tuesday before gradually lowering beginning Wednesday.
Temperatures will drop into the normal range today and to below
normal starting Tuesday. Drying conditions later this week should
mostly end rain chances by Thursday with MinRHs dropping back into
the teens.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Flood Watch until 9 PM MST this evening for AZZ530>533-535-536-
539-559.
Blowing Dust Advisory from 2 PM this afternoon to 6 PM MST this
evening for AZZ539-551-553-554-559.
CA...Flood Watch until 9 PM PDT this evening for CAZ562>567-569-570.
&&
SHORT TERM...Kuhlman
LONG TERM...Kuhlman
AVIATION...Frieders
FIRE WEATHER...KuhlmanThe Yuma radar (KYUX), 37 km away, was scanning. The volume nearest the first event began at 19:49 UTC.
11 thunderstorm wind, 5 flash flood. Local standard time, as filed.
Caltrans reported downed power lines blocking both directions of I-8 near the Gordons Well Road exit. No injuries were reported. Time estimated by radar.
Power poles were reported down across SR-115, blocking both directions of the roadway. No injuries were reported. Time estimated from radar.
Multiple down power poles and power lines were reported near I-8 and Bonds Corner Road. This included downed high voltage transmission lines. Multiple motorists and nearby residents were reported to be trapped in the Holtville area due to all the downed power poles and power lines. No injuries were reported. Time estimated from radar.
Five power poles were reported down along SR-115 near Evan Hewes Highway. Additionally, the Imperial Irrigation District reported approximately 50 power poles were down west of Holtville. In Holtville, two homes were reported to be damaged after trees were blown over onto the structures. The tree at one of the homes also destroyed a vehicle. No injuries were reported.
Video showed multiple downed power poles across a railroad track at Neckel Road east of Highway 86. The Imperial Irrigation District reported multiple downed power poles across the railroad tracks between Brawley and Imperial. No injuries were reported.
The El Centro Naval Air Facility (KNJK) recorded a gust of 59 mph.
Multiple power poles and power lines were reported down across the roadway near Highway 86 and Harris Road. No injuries were reported.
Brockman Road and Lyons Road was closed due to downed power lines. No injuries were reported. Time estimated from radar.
Multiple power poles and power lines were reported down along Highway 78, going across the lanes of the roadway. No injuries were reported.
A semi truck was blown over along Highway 86, injuring the truck driver. A power pole and power lines were also reported down in the area.
Four semi trucks were reported to be flipped over with power lines over the trucks. Images also showed multiple power poles down in the area. No injuries were reported. Time estimated from radar.
Video showed flooding along Highway 98 near Drew Road. Highway 98 was closed from Imperial Highway to Brockman Road due to the flooding. Timing estimated from radar.
Significant flash flooding occurred along Highway 86 near Highway 78, leaving numerous motorists stranded on the flooded roadway. According to reports, up to 200 motorists were left stranded along Highway 86, with videos showing floodwaters that appeared to be around 3 to 5 feet deep over the roadway. Videos and images showed vehicles floating on the roadway with several vehicles almost completely submerged by the floodwaters. Multiple motorists were left stranded on top of their vehicles before being rescued. Portions of the roadway were also washed out by the flooding. No injuries or fatalities were reported.
Ogilby Road between I-8 and Highway 78 was closed due to flooding. Timing estimated from radar.
A portion of Split Mountain Road at Fish Creek Wash was washed out due to flooding. Time estimated based on radar.
Flash flooding was reported along Park Boulevard near the north entrance of Joshua Tree National Park. Flooding across the roadway resulted in boulders around 1 to 2 feet in diameter being swept into the roadway.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2025Every state in 2025This day in weather historyWarnings in California, August 2025
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: 1293083, 1293084, 1293085, 1293087, 1293146, 1293097, 1293086, 1293126, 1293088, 1293107, 1293096, 1292955, 1292960, 1292956, 1292957, 1293123.