Alert archive / California / Flash Flood Watches in 2021
Flash Flood Watch 4, NWS San Diego, CA
NWS San Diego, CA issued this flash flood watch at Jul 18, 2021, 8:07 AM PDT for Riverside County, San Diego County, California. It took effect at Jul 18, 2021, 12:00 PM PDT. It was in force for 7 hr.
The area
The counties it named.
The facts
- Issued
- Jul 18, 2021, 8:07 AM PDT (15:07 UTC)
- In effect from
- Jul 18, 2021, 12:00 PM PDT
- Expired
- Jul 18, 2021, 7:00 PM PDT
- In force
- 7 hr
- Issued by
- NWS San Diego, CA
- Flood severity
- None
Counties Riverside County, CA, San Diego County, CA
The radar
The San Diego radar (KNKX), 80 km from the middle of the area, began a volume at 15:07 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.
The nearest sounding before it
San Diego, CA (KNKX), launched 12:00Z, 3.1 hours before the alert went out and 100 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
- 1406 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- -12 m²/s²
- 0-3 km storm-relative helicity
- 82 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.0
The text
As transmitted.
583 WGUS66 KSGX 181507 FFASGX URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch National Weather Service San Diego CA 807 AM PDT Sun Jul 18 2021 CAZ056-058-182315- /O.NEW.KSGX.FF.A.0004.210718T1900Z-210719T0200Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Riverside County Mountains-San Diego County Mountains- Including the cities of Julian, Pine Valley, and Idyllwild-Pine Cove 807 AM PDT Sun Jul 18 2021 ...FLASH FLOOD WATCH IN EFFECT FROM NOON TODAY TO 7 PM PDT THIS EVENING... The National Weather Service in San Diego has issued a * Flash Flood Watch for a portion of southwest California, including the following areas, Riverside County Mountains and San Diego County Mountains. * From Noon today to 7 PM PDT this evening * Monsoonal moisture and daytime heating are expected to result in strong thunderstorms over the mountains this afternoon. Heavy downpours may lead to local flash flooding of small steams and normally dry washes along the desert foothills. * Recently burned areas will be particularly susceptible to flash flooding and debris flows. PRECAUTIONARY/PREPAREDNESS ACTIONS... Stay away or be swept away. River banks and culverts can become unstable and unsafe. Do not enter water of unknown depth. Turn around, don't drown. && $$ 10
2 follow-up statements
647 WGUS66 KSGX 181954 FFASGX Flood Watch National Weather Service San Diego CA 1254 PM PDT Sun Jul 18 2021 CAZ056-058-190200- /O.CON.KSGX.FF.A.0004.000000T0000Z-210719T0200Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Riverside County Mountains-San Diego County Mountains- Including the cities of Julian, Pine Valley, and Idyllwild-Pine Cove 1254 PM PDT Sun Jul 18 2021 ...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 7 PM PDT THIS EVENING... The Flash Flood Watch continues for * A portion of southwest California, including the following areas, Riverside County Mountains and San Diego County Mountains. * Until 7 PM PDT this evening * Monsoonal moisture and daytime heating are expected to result in strong thunderstorms over the mountains this afternoon. Heavy downpours may lead to local flash flooding of small steams and normally dry washes along the desert foothills. * Recently burned areas will be particularly susceptible to flash flooding and debris flows. PRECAUTIONARY/PREPAREDNESS ACTIONS... Stay away or be swept away. River banks and culverts can become unstable and unsafe. Do not enter water of unknown depth. Turn around, don't drown. && $$ 10
097 WGUS66 KSGX 190157 FFASGX Flood Watch National Weather Service San Diego CA 657 PM PDT Sun Jul 18 2021 CAZ056-058-190300- /O.EXP.KSGX.FF.A.0004.000000T0000Z-210719T0200Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Riverside County Mountains-San Diego County Mountains- Including the cities of Julian, Pine Valley, and Idyllwild-Pine Cove 657 PM PDT Sun Jul 18 2021 ...FLASH FLOOD WATCH WILL EXPIRE AT 7 PM PDT THIS EVENING... The Flash Flood Watch for a portion of southwest California, including the following areas, Riverside County Mountains and San Diego County Mountains will expire AT 7 PM PDT this evening. The threat of flooding continues to decrease. Please continue to heed remaining road closures. $$ PG
The office that day
Everything else NWS San Diego, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 18, 1:31 PM PDT | Special Weather Statement | SGX | San Diego | 44 min |
| Jul 18, 2:05 PM PDT | Areal Flood Advisory | SGX | San Diego | 58 min |
Nearby
Flash Flood Watches in California, 2021Every flash flood watch in 2021
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.