A cut off upper level low moved over SoCal on April 29th, bringing showers and thunderstorms to most of the region. 20.
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 SGX wrote it up.
A cut off upper level low moved over SoCal on April 29th, bringing showers and thunderstorms to most of the region. The mountain and valley areas received around 0.50 to 1 of precipitation, while the coastal areas only received around 0.10 to 0.20. Graupel fell in the San Bernardino Mountains.
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 San Diego, CA wrote its last area forecast discussion before the first event at Apr 29, 8:37 AM PST, 1 hour 23 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
937 AM PDT Mon Apr 29 2019
.SYNOPSIS...
A low pressure system will move across southern California today
bringing cooling, scattered showers and a slight chance of
thunderstorms. Winds will become strong along the desert
mountain slopes to portions of the deserts. Light precipitation
may continue at times for tonight into Tuesday morning along and
west of the mountains from a deep marine layer. High pressure
aloft will move towards California bringing dry weather with a
warming trend for Wednesday through Friday. Another low pressure
system will move towards southern California bringing a cooling
trend for Saturday through Monday with a chance of showers for
late Sunday into Monday.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
...Update...
A few light showers are moving onshore the coast this morning
around the east side of an upper low over the California Bight.
This low will move inland over Southern California this
afternoon. HREF shows MUCAPE low throughout the day, but does
increase to about 500 J/KG over northeast areas, so a
thunderstorm will be possible, mainly from the San Bernardinos/San
Jacintos points northeast this afternoon. Precipitation amounts
will continue to be light. West winds will strengthen this
afternoon/early this evening with gusts along the desert slopes
and into parts of the deserts (windiest lower deserts) of 40-50
mph.
...Previous Discussion (Issued at 323 AM PDT Mon Apr 29 2019)...
.SHORT TERM (Today through Wednesday)...
Satellite imagery early this morning shows a closed upper level
low pressure system over the eastern Pacific centered south of
Point Conception and west of San Diego. It will continue to move
slowly eastward today, moving into southwestern California during
the late morning and into northwestern Arizona by early evening.
It will then weaken and move inland more quickly.
Scattered showers and isolated thunderstorms have continued
overnight. There were a number of lightning strikes Sunday
afternoon and evening over the coastal waters with a few
overnight...mostly across the eastern slopes of the Riverside
County mountains and across portions of the Coachella valley.
The sounding from Miramar late Sunday afternoon showed a deep dry
subcloud layer below 700 mb. Most rainfall overnight has been a
trace to a few hundredths of an inch.
The HREF shows the most unstable CAPE values of 250 to 500 J/kg,
that were over the mountains and high desert areas, have mostly
moved off to the north and east. Most unstable CAPE values of a
few hundred J/kg, near the center of the upper low, will move to
near the coast around 12Z (5 AM), then move inland during the
morning and early afternoon. The atmosphere will stabilize from
the west from mid afternoon through early evening as the upper low
moves off to the east. Scattered showers and isolated
thunderstorms should spread inland during the morning, moving off
to the east during the early evening. Scattered mostly light
showers will continue for tonight into Tuesday morning along and
west of the mountains.
Given the showery nature of the precipitation, rainfall will be
highly variable but will generally range from less than one
quarter inch at lower elevations to one quarter to one half inch
in the mountains with locally greater amounts. Snow levels will
mostly be above 7500 to 8000 feet.
With the approach of the upper low, the marine layer has deepened
with coastal low clouds extending inland onto the coastal
mountain slopes. This deep marine layer will continue into
Tuesday, then begin to become shallower for late Tuesday night and
Wednesday.
Stronger onshore flow today with bring gusty west winds to desert
slopes of the mountains into the deserts into this evening with a
wind advisory in effect.
Today is expected to be the coolest day with slow warming on
Tuesday and greater warming on Wednesday, but with high
temperatures still a few degrees below average on Wednesday.
&&
.LONG TERM (Thursday through Sunday)...
Warming will continue for Thursday and Friday as high pressure
aloft moves inland across California. The marine layer will become
shallower with night and morning coastal low clouds and fog not
spreading as far into the valleys.
Temperatures will cool for Saturday through early next week as
another closed low pressure system moves toward southern
California. WPC favors the slower timing of the ECMWF and ECMWF
ensemble mean. The timing differences are mostly on Saturday into
early Sunday with timing much closer beginning late Sunday, though
with some continuing track differences.
Aside from the cooling trend for Saturday through early next week,
the marine layer will deepen with night and morning clouds and fog
spreading farther into the valleys, then onto the coastal mountain
slopes. There is also a chance of showers for late Sunday into
Monday with details dependent on the track and timing of the upper
low.
&&
.AVIATION...
291600Z...Coast/Valleys/Mountain Slopes...Low clouds and -SHRA will
continue into this evening with bases between 1500-3500 feet MSL and
VIS locally 2-5SM in SHRA. Slight chance of -TSRA most likely
between 18-01Z. Brief scatter out is possible this afternoon, likely
near the coast.
Mountains/Deserts...SCT-BKN clouds between 7000-10000 feet msl along
with -SHRA and isolated -TSRA. Areas of west winds 15-25 knots with
gusts to 45 knots on the desert mountain slopes and at times onto
the desert floors, along with moderate UDDFS and local LLWS.
Winds to decrease and clearing expected after 04Z tonight.
&&
.MARINE...
Slight chance of thunderstorms through this evening. A Marine
Weather Statement contains the details. Otherwise, no hazardous
marine conditions are expected through Thursday.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 11 PM PDT this evening for Coachella Valley-
San Diego County Deserts-San Gorgonio Pass Near Banning.
PZ...NONE.
&&
PUBLIC...Gregoria (Update)/17 (Prev Discussion)
AVIATION/MARINE...ConnollyThe national radar mosaic for the moment the first event began.
1 hail, 1 lightning. Local standard time, as filed.
Graupel/hail reported near Onyx Peak in the San Bernardino Mountains around 10 AM PST on April 29th.
Lightning over San Diego County and the waters totaled 69 cloud to ground lightning strikes on April 29th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2019Every state in 2019This day in weather historyWarnings in California, April 2019
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: 819476, 819881.