Alert archive / California / Flash Flood Warnings in 2018
Flash Flood Warning 34, NWS San Diego, CA
NWS San Diego, CA issued this flash flood warning at Dec 6, 2018, 3:58 PM PST for Riverside County, San Bernardino County, California. It was in force for 2 hr. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Dec 6, 2018, 3:58 PM PST (23:58 UTC)
- Expired
- Dec 6, 2018, 6:14 PM PST
- In force
- 2 hr
- Issued by
- NWS San Diego, CA
- Area
- Storm-based polygon
- Flood severity
- None
The radar
The Santa Ana Mts radar (KSOX), 60 km from the middle of the area, began a volume at 00:04 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
Did it verify
Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.
Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.
The nearest sounding before it
San Diego, CA (KNKX), launched 12:00Z, 12.0 hours before the alert went out and 137 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1084 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 194 m²/s²
- 0-3 km storm-relative helicity
- 207 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
613
WGUS56 KSGX 062358
FFWSGX
CAC065-071-070300-
/O.NEW.KSGX.FF.W.0034.181206T2358Z-181207T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Diego CA
358 PM PST THU DEC 6 2018
The National Weather Service in San Diego has issued a
* Flash Flood Warning for...
San Bernardino County in southern California...
Riverside County in southern California...
* Until 700 PM PST
* At 356 PM PST, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Flash flooding will likely begin
shortly. In addition, excessive rainfall will likely result in
debris flows within and downstream of the Valley Fire burn scar.
The debris flow can consist of rock, mud, vegetation and other
loose materials.
* Rainfall rates will locally exceed one-half inch per hour.
* Some locations that will likely experience flooding include...
Riverside, San Bernardino, Moreno Valley, Redlands, Yucaipa, Forest
Falls, Lake Arrowhead, western Mount San Gorgonio, Hemet and Hwy
243 Between Banning And Idyllwild.
LAT...LON 3414 11684 3394 11682 3367 11708 3397 11734
3431 11729
$$
Maxwell2 follow-up statements
305
WGUS76 KSGX 070047
FFSSGX
Flash Flood Statement
National Weather Service San Diego CA
447 PM PST THU DEC 6 2018
CAC065-071-070300-
/O.CON.KSGX.FF.W.0034.000000T0000Z-181207T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-Riverside CA-
447 PM PST THU DEC 6 2018
...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 700 PM PST FOR SAN
BERNARDINO AND RIVERSIDE COUNTIES...
At 444 PM PST, Doppler radar indicated thunderstorms producing areas
of heavy rain across the warned area. The thunderstorms had weakened
slightly, but debris flow is possible in the Valley Fire burn scar
through around 530 PM as some heavy rains move through that area.
LAT...LON 3414 11684 3394 11682 3367 11708 3397 11734
3431 11729
$$
Maxwell225
WGUS76 KSGX 070214
FFSSGX
Flash Flood Statement
National Weather Service San Diego CA
614 PM PST THU DEC 6 2018
CAC065-071-070223-
/O.CAN.KSGX.FF.W.0034.000000T0000Z-181207T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-Riverside CA-
614 PM PST THU DEC 6 2018
...THE FLASH FLOOD WARNING FOR SAN BERNARDINO AND RIVERSIDE COUNTIES
IS CANCELLED...
Flooding is no longer expected to pose a threat. The rainfall rates
have diminished greatly since 500 PM, including near the Valley Fire
burn area.
LAT...LON 3414 11684 3394 11682 3367 11708 3397 11734
3431 11729
$$
MaxwellWhat forecasters said that day
The local office's own words before this flash flood warning went out, 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 this flash flood warning went out at Dec 6, 2:19 PM PST, 1 hour 39 minutes earlier.
Area forecast discussion, Dec 6, 2:19 PM PST, 1 hour 39 minutes before
Area Forecast Discussion
National Weather Service San Diego CA
219 PM PST Thu Dec 6 2018
.SYNOPSIS...
A slow moving low pressure system will continue to bring periods
of heavy showers and isolated thunderstorms through this evening,
ending by daybreak Friday. Flooding will be possible through this
evening area wide with heavy snow in the San Bernardino Mountains.
Dry with a warming trend trough the weekend with high pressure
aloft and with weak offshore flow bringing gusty northeast winds
near the coastal mountain slopes. A low pressure system from the
northwest will bring cooler weather and chance for showers on
Tuesday, followed by dry weather with a warming trend for
Wednesday and Thursday.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Bands of very heavy showers continue to stream onshore with a band
of embedded thunderstorms to the south moving east towards the San
Diego County coast with enhanced area instability noted in the
vicinity of strong shortwave rotating onto the coast. Precip
rates up to 1" per hour have been common with the heaviest
showers and have prompted reports of flash flooding in Orange
County. Main concern for additional flash flooding in urbanized
areas and near wildfire burn scars and the flash flood watch was
expanded to include the entire area. Small stream flooding likely
in poor drainage areas. Holy and Canyon Complex burn scars most
susceptible to debris flows this afternoon but cannot rule out
debris flow near other recent scars including Cranston.
Snow levels will continue to fluctuate between 6000-7000 feet in
the San Bernardino Mountains. Some colder air in noted just to the
NW and should wrap into the San Bernardino Mountains later this
afternoon providing lower snow levels as the upper low drops south
and allows some colder air to advect from the north. In addition
heavier convection and evaporative cooling will prompt lower snow
levels at times possibly as low as 5000 feet through this evening.
Winter storm warning remains in effect for locations 6000 feet
and higher in San Bernardino County with additional accumulations
of 3 to 6 inches between 6000 to 7000 feet, and 6 to 12 inches
with isolated higher amounts up to 18 inches above 7000 feet. Snow
levels higher in Riverside County so only the high peaks there
will receive accumulating snow including Mount San Jacinto and
Toro Peak.
Precipitation will taper off from NW to SE after midnight and
taper off by daybreak Friday.
High pressure aloft will move across the West Coast this weekend
bringing dry weather with a warming trend for Friday through the
weekend. There will also be weak offshore flow this weekend with
gusty northeast winds near the coastal slopes of the mountains.
Monday will be slightly cooler as high pressure aloft begins to
weaken and onshore flow returns. For Tuesday, a trough from the
northwest will bring cooler conditions with gusty west to
northwest winds, and a chance for mainly light precipitation.
Dry with a warming trend Wednesday and Thursday with a period of
weak offshore flow possible around Wednesday.
&&
.AVIATION...
062000Z...A band of very heavy rain over Orange County and the
coastal waters will slowly drift east through 06Z. Scattered showers
ahead of this trough. CIGS 025-035 with vis 2-4 miles in showers,
lowering to CIGS of 010 and vis less than 1 mile in the heavy
downpours. A slight chance of TS. Intermittent terrain obscurations
in the mountains. East and southeast winds 15-25 kt in the mountains
and foothills. Showers decreasing late tonight.
&&
.MARINE...
Hazardous boating conditions through this evening with bands of
heavy rain and isolated thunderstorms. South winds of 10-20 kt
gusting to 25 kt. A Marine Weather Statement is in effect through
this evening.
&&
.BEACHES...
Bands of heavy rain and isolated thunderstorms over the coastal
waters will move over the beaches this afternoon and evening. A
building long-period swell through Friday will bring surf as high as
6 feet tonight into Saturday, particularly to southern San Diego
County. Strong rip currents are likely. For details, check the Surf
Zone Forecast.
&&
.SKYWARN...
Skywarn activation is requested for all areas. Weather spotters
are encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Flash Flood Watch until midnight PST tonight for Apple and
Lucerne Valleys-Coachella Valley-Orange County Coastal
Areas-Orange County Inland Areas-Riverside County Mountains-
San Bernardino County Mountains-San Bernardino and
Riverside County Valleys-The Inland Empire-San Diego County
Coastal Areas-San Diego County Deserts-San Diego County
Mountains-San Diego County Valleys-San Gorgonio Pass Near
Banning-Santa Ana Mountains and Foothills.
Winter Storm Warning until midnight PST tonight for San
Bernardino County Mountains.
PZ...NONE.
&&
PUBLIC...Brotherton
AVIATION/MARINE...MoedeIn the hours before
Local storm report, Dec 6, 3:26 PM PST, 32 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN DIEGO CA
326 PM PST THU DEC 6 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0311 PM DEBRIS FLOW 9 WNW LAKE ELSINORE 33.73N 117.45W
12/06/2018 RIVERSIDE CA LAW ENFORCEMENT
LAKE ELSINORE POLICE REPORTED THAT WATER AND
MUD BREACHED A K-RAIL IN A NEIGHBORHOOD.
&&
SCLocal storm report, Dec 6, 3:30 PM PST, 28 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN DIEGO CA
330 PM PST THU DEC 6 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0326 PM DEBRIS FLOW 6 WSW LAKE ELSINORE 33.64N 117.42W
12/06/2018 RIVERSIDE CA LAW ENFORCEMENT
LAW ENFORCEMENT REPORTS LONG CANYON ROAD AT
SR 74 COMPLETELY WASHED OUT.
&&
SCLocal storm report, Dec 6, 3:40 PM PST, 18 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN DIEGO CA
340 PM PST THU DEC 6 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0339 PM FLOOD 2 E OCEANSIDE 33.20N 117.35W
12/06/2018 SAN DIEGO CA TRAINED SPOTTER
FLOODED STREET, LOTS OF DEBRIS (E.G. TREE
BRANCHES).
&&
COLocal storm report, Dec 6, 3:42 PM PST, 16 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN DIEGO CA
342 PM PST THU DEC 6 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0340 PM SNOW BIG BEAR LAKE 34.24N 116.93W
12/06/2018 E2.0 INCH SAN BERNARDINO CA TRAINED SPOTTER
SPOTTER IN BIG BEAR REPORTED UP TO 2 INCHES
OF SNOW PER HOUR IN THE BIG BEAR AREA.
&&
SCLocal storm report, Dec 6, 3:44 PM PST, 14 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN DIEGO CA
344 PM PST THU DEC 6 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0330 PM DEBRIS FLOW 5 W LAKE ELSINORE 33.68N 117.40W
12/06/2018 RIVERSIDE CA FIRE DEPT/RESCUE
FLASH FLOODING AND DEBRIS FLOW. 20 RESIDENTS
REQUIRING RESCUE ON COBBLESTONE LN IN LAKE
ELSINORE.
&&
MOEDELocal storm report, Dec 6, 3:45 PM PST, 13 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN DIEGO CA
345 PM PST THU DEC 6 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0344 PM LIGHTNING 1 SSW BONITA 32.66N 117.02W
12/06/2018 SAN DIEGO CA TRAINED SPOTTER
LIGHTNING WITHIN 5 MI. OF THIS LOCATION.
&&
COThe office that day
Everything else NWS San Diego, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 6, 9:11 AM PST | Flash Flood Watch | SGX | Orange, Riverside, San Bernardino, San Diego | 15 hr |
| Dec 6, 9:29 AM PST | Areal Flood Advisory | SGX | Orange, Riverside, San Bernardino | 3 hr |
| Dec 6, 10:10 AM PST | Winter Storm Warning | SGX | San Bernardino | 14 hr |
| Dec 6, 11:19 AM PST | Flash Flood Warning | SGX | Orange | 3 hr |
| Dec 6, 12:29 PM PST | Areal Flood Advisory | SGX | Orange, Riverside, San Bernardino | 3 hr |
| Dec 6, 1:05 PM PST | Flash Flood Warning | SGX | Orange, Riverside | 3 hr |
| Dec 6, 2:08 PM PST | Flash Flood Warning | SGX | San Bernardino | 3 hr |
| Dec 6, 3:17 PM PST | Areal Flood Advisory | SGX | Orange, Riverside, San Bernardino, San Diego | 3 hr |
Nearby
Flash Flood Warnings in California, 2018Every flash flood warning in 2018
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.