Alert archive / California / Flash Flood Warnings in 2011

Flash Flood Warning 3, NWS San Francisco Bay Area, CA

March 24, 2011Santa Cruz County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Mar 24, 2011, 4:04 PM PDT for Santa Cruz County, California. It was in force for 56 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Mar 24, 2011, 4:04 PM PDT (23:04 UTC)
Expired
Mar 24, 2011, 5:00 PM PDT
In force
56 min
Issued by
NWS San Francisco Bay Area, CA
Area
Storm-based polygon
Flood severity
None

County Santa Cruz County, CA

The radar

The San Francisco radar (KMUX), 17 km from the middle of the area, began a volume at 23:06 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

Oakland, CA (KOAK), launched 12:00Z, 11.1 hours before the alert went out and 84 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.

Skew-T log-pSkew-T log-p diagram, Oakland, CA at 12:00Z on 2011-03-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 152 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Oakland, CA at 12:00Z on 2011-03-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 121 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
152 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
587 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
121 m²/s²
0-3 km storm-relative helicity
154 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

620 
WGUS56 KMTR 242304
FFWMTR
CAC087-250000-
/O.NEW.KMTR.FF.W.0003.110324T2304Z-110325T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
404 PM PDT THU MAR 24 2011

THE NATIONAL WEATHER SERVICE IN THE SAN FRANCISCO BAY AREA HAS
ISSUED A

* FLASH FLOOD WARNING FOR...
  THE SOQUEL CREEK IN SANTA CRUZ COUNTY IN WESTERN CALIFORNIA...

* UNTIL 500 PM PDT.

* AT 355 PM PDT...NWS DOPPLER RADAR AND AUTOMATED RAIN GAGES         
  INDICATED HEAVY RAINFALL MOVING THROUGH THE AREA OVER THE LAST     
  TWO HOURS. THE SOQUEL CREEK AT SOQUEL IS NOW AT JUST UNDER         
  FLOOD STAGE OF 14.5 FEET AND IS EXPECTED TO REACH OR EXCEED FLOOD  
  STAGE WITHIN THE NEXT HOUR. RAINFALL IS EXPECTED TO TAPER OFF      
  WITHIN THE NEXT 30 MINUTES...BUT THE CREEK WILL CONTINUE TO RISE   
  EVEN AFTER RAIN RATES DECREASE.

* LOCATIONS IN THE WARNING INCLUDE COMMUNITIES AND INTERESTS ALONG   
  THE SOQUEL CREEK.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS
IMMINENT.

RUNOFF FROM HEAVY RAINFALL WILL CAUSE LOCALIZED FLOODING OF SMALL
CREEKS AND STREAMS AS WELL AS ROADWAYS...UNDERPASSES AND OTHER LOW
LYING SPOTS. DO NOT ATTEMPT TO CROSS SWIFTLY FLOWING WATER OR WATER
OF UNKNOWN DEPTH. TURN AROUND...DONT DROWN.

IT IS IMPORTANT FOR CAMPERS AND HIKERS TO KNOW WHERE THEY ARE
RELATIVE TO CREEKS...STREAMS...OR RIVERS WHICH CAN BECOME DANGEROUS
IN HEAVY RAINS. BE PARTICULARLY AWARE IN HILLY TERRAIN WHERE MANY LOW
WATER CROSSINGS CAN QUICKLY BECOME KILLERS.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE.

LAT...LON 3713 12201 3708 12186 3695 12188 3695 12190
      3697 12192 3697 12194 3695 12196 3695 12199
      3695 12200

$$

DYKEMA
1 follow-up statement
355 
WGUS76 KMTR 250007
FFSMTR

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
507 PM PDT THU MAR 24 2011

CAC087-250012-
/O.EXP.KMTR.FF.W.0003.000000T0000Z-110325T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SANTA CRUZ CA-
507 PM PDT THU MAR 24 2011

...THE FLASH FLOOD WARNING HAS EXPIRED FOR THE SOQUEL CREEK IN SANTA 
CRUZ COUNTY...

THE SOQUEL CREEK AT SOQUEL CRESTED ABOUT A HALF FOOT BELOW FLOOD 
STAGE AT 4:30 PM PDT THIS AFTERNOON. THE CREEK HAS BEEN RECEDING 
SINCE THAT TIME. THEREFORE...THE FLASH FLOOD WARNING FOR THE SOQUEL 
CREEK IN SANTA CRUZ COUNTY HAS BEEN ALLOWED TO EXPIRE. SHOWERS WILL 
CONTINUE ACROSS THE CREEK BASIN THROUGH THE EVENING HOURS...AND 
BRIEF HEAVY DOWNPOURS ARE POSSIBLE. HOWEVER...FLOODING IS NO LONGER 
EXPECTED ALONG THE SOQUEL CREEK.

LAT...LON 3713 12201 3708 12186 3695 12188 3695 12190
      3697 12192 3697 12194 3695 12196 3695 12199
      3695 12200

$$

DYKEMA

The office that day

Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 23, 10:27 PM PDTAreal Flood AdvisoryMTRMonterey, San Benito, Santa Clara, Santa Cruz19 hr
Mar 24, 3:45 AM PDTHigh Surf AdvisoryMTRMarin, Monterey, City and County of San Francisco, San Mateo, Santa Cruz, Sonoma20 hr
Mar 24, 12:06 PM PDTSpecial Weather StatementMTRSan Mateo39 min
Mar 24, 2:55 PM PDTHigh Surf WarningMTRMarin, Monterey, City and County of San Francisco, San Mateo, Santa Cruz, Sonoma24 hr
Mar 24, 3:05 PM PDTSmall Craft AdvisoryMTR42 hr
Mar 24, 3:08 PM PDTFlash Flood WarningMTRSanta Cruz3 hr

Nearby

Flash Flood Warnings in California, 2011Every flash flood warning in 2011

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.