Flash Flood Warning 42, NWS San Diego, CA

184 
WGUS76 KSGX 292056
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
156 PM PDT THU AUG 29 2013

CAC073-292300-
/O.CON.KSGX.FF.W.0042.000000T0000Z-130829T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN DIEGO CA-
156 PM PDT THU AUG 29 2013

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 PM PDT FOR
SOUTHEASTERN SAN DIEGO COUNTY...

AT 148 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE HEAVY RAIN PRODUCING FLASH FLOODING OVER THE WARNED AREA. 
ONE HOUR RAINFALL RATES IN WITH THESE THUNDERSTORMS ARE RANGING 
BETWEEN 1 AND 1.5 INCHES.  STATE ROUTE 2 AS WELL AS INTERSTATE 8 MAY 
BE IMPACTED BY FLASH FLOODING OR DEBRIS FLOWS.  THE EASTERN PORTION 
OF THE CHARITY BURN SCAR IS ALSO INCLUDED IN THE WARNED AREA...SO 
DEBRIS FLOWS ARE POSSIBLE AS WELL.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO AGUA CALIENTE
SPRINGS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THE WATERSHEDS BURNED THIS FALL ARE PARTICULARLY SUSCEPTIBLE TO FLASH
FLOODS AND DEBRIS FLOWS DURING RAINSTORMS. A SHORT PERIOD OF EVEN
MODERATE RAINFALL ON A BURNED WATERSHED CAN LEAD TO DEBRIS FLOWS.
RAINFALL THAT IS NORMALLY ABSORBED INTO HILLSLOPE SOILS CAN RUN OFF
ALMOST INSTANTLY AFTER VEGETATION HAS BEEN REMOVED BY WILDFIRE. THIS
CAUSES MUCH GREATER AND MORE RAPID RUNOFF THAN IS NORMAL FROM CREEKS
AND DRAINAGE AREAS. THE HIGHLY ERODIBLE SOILS IN A BURN SCAR ALLOW
FLOOD WATERS TO ENTRAIN LARGE AMOUNTS OF ASH, MUD...BOULDERS...AND
UNBURNED VEGETATION. WITHIN THE BURNED AREA AND DOWNSTREAM...THE
FORCE OF RUSHING WATER...SOIL AND ROCK CAN DESTROY CULVERTS...
BRIDGES...ROADWAYS AND BUILDINGS...POTENTIALLY CAUSING INJURY OR
DEATH.

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

&&

LAT...LON 3302 11649 3310 11608 3308 11607 3307 11609
      3262 11610 3260 11631

$$

PALMER

340 
WGUS76 KSGX 292208
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
308 PM PDT THU AUG 29 2013

CAC073-292300-
/O.CON.KSGX.FF.W.0042.000000T0000Z-130829T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN DIEGO CA-
308 PM PDT THU AUG 29 2013

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 PM PDT FOR
SOUTHEASTERN SAN DIEGO COUNTY...

AT 400 PM PST...DOPPLER RADAR CONTINUES TO INDICATE LIGHT TO 
MODERATE SHOWERS OVER THE WARNED AREA.  ALTHOUGH THE HEAVY RAIN HAS 
ENDED...ADDITIONAL FLASH FLOODING MAY BE POSSIBLE ON THE DESERT 
SLOPES AND DESERT FLOOR AS THE RUNOFF CONTINUES OVER THE NEXT FEW 
HOURS.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO MOUNT LAGUNA

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

&&

LAT...LON 3302 11649 3310 11608 3308 11607 3307 11609
      3262 11610 3260 11631

$$

PALMER

465 
WGUS76 KSGX 292254
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
354 PM PDT THU AUG 29 2013

CAC073-292303-
/O.EXP.KSGX.FF.W.0042.000000T0000Z-130829T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN DIEGO CA-
354 PM PDT THU AUG 29 2013

...THE FLASH FLOOD WARNING WILL EXPIRE AT 400 PM PDT FOR SOUTHEASTERN
SAN DIEGO COUNTY...

SHOWERS AND THUNDERSTORMS OVER THE WARNED AREA HAVE DISSIPATED.  
ALTHOUGH ADDITIONAL RUNOFF MAY BE POSSIBLE ALONG THE DESERT 
FLOOR...THE FLASH FLOOD WARNING WILL BE ALLOWED TO EXPIRE AT 4 PM.  


LAT...LON 3302 11649 3310 11608 3308 11607 3307 11609
      3262 11610 3260 11631

$$

PALMER

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
922 AM PDT THU AUG 29 2013

.SYNOPSIS...
A BROAD SUBTROPICAL HIGH OVER THE CENTRAL PART OF THE COUNTRY WILL
STEER MONSOONAL MOISTURE ACROSS SOUTHERN CALIFORNIA THROUGH THE
WEEKEND BRINGING WARM AND HUMID CONDITIONS. SHOWERS AND
THUNDERSTORMS WILL REDEVELOP OVER THE MOUNTAINS AND DESERTS TODAY
WITH A FEW DRIFTING WEST INTO THE VALLEYS. LOCALLY HEAVY RAIN AND
FLASH FLOODING IS POSSIBLE. CLOUDS WILL INCREASE ON FRIDAY...THEN
GRADUALLY THIN SATURDAY AS A WEAK TROPICAL WAVE PASSES. SOME DRYING
AND REESTABLISHMENT OF A MARINE LAYER IS LIKELY NEXT WEEK WITH
SLIGHTLY BETTER ONSHORE FLOW BUT HIGH PRESSURE ALOFT WILL KEEP THE
WEATHER WARM.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

THE MARINE LAYER AND ASSOCIATED STRATUS WAS WELL OUT TO SEA THIS
MORNING...BUT MONSOONAL MOISTURE INCREASING FROM THE SE WAS BRINGING
MID AND HIGHER CLOUDS INTO THE AREA FROM THE LOWER DESERTS. THE NKX
SOUNDING SHOWED AN INCREASE TO 1.67 INCHES...AND DEWPOINTS AND PW
HAVE SURGED ACROSS THE LOWER DESERTS. SFC PRESSURE GRADIENTS WERE
WEAK AND SLIGHTLY OFFSHORE. WINDS HAVE BACKED AROUND TO EASTERLY AT
5-15 KT IN THE MID LEVELS.

LOOKS LIKE A WARM AND INCREASINGLY HUMID DAY WEST OF THE MOUNTAINS
WITH PERIODS OF MID-HIGH CLOUDS AND EVEN A FEW THUNDERSTORMS
POSSIBLE BY AFTERNOON. WITHOUT THE MARINE LAYER...TEMPERATURES WILL
RISE QUICKLY INTO THE 80S ALL THE WAY TO THE COAST...AND WELL INTO
THE 90S A FEW MILES INLAND...PROVIDED CLOUDS PERMIT ENOUGH SUN.

THE VERY HIGH PW OVER THE DESERTS SUPPORTS VERY HEAVY RAINFALL RATES
IN THUNDERSTORMS THAT DEVELOP THERE AND OVER THE MOUNTAINS AS OUR
ATMOSPHERE BECOMES MORE TROPICAL. ANOTHER CONCERN WILL BE GUSTY
OUTFLOW WINDS OVER THE DESERTS AND ADJACENT MOUNTAIN SLOPES. THE
ONLY LIMITING FACTOR FOR CONVECTION AT THIS POINT LOOKS TO BE THE
ABUNDANCE OF HIGHER CLOUDS APPROACHING FROM THE LOWER COLORADO RIVER
VALLEY. HOWEVER...WITH CONVECTION ALREADY ACTIVE OVER NORTHERN
BAJA...EVEN LIMITED SUN IN THESE AREAS SHOULD FIRE OFF INTENSE
CONVECTION. SO A FLASH FLOOD WATCH IS IN EFFECT THROUGH THIS EVENING.

MODELS ARE TRACKING AND WATER VAPOR IMAGERY CONFIRMS A WEAK TROPICAL
WAVE OVER NW MEXICO THAT WILL MOVE NW AROUND THE PERIPHERY OF THE
MASSIVE SUBTROPICAL HIGH. AS THIS FEATURE APPROACHES TONIGHT AND
MOVES OVER THE REGION ON FRI...CLOUDS WILL INCREASE AND BECOME MORE
PERSISTENT. THERE WILL BE A CHANCE OF SHWRS/TSTMS ACCOMPANYING THIS
FEATURE OVERNIGHT AND ON FRI...BUT INTENSE CONVECTION IS LIKELY TO
BE SUBDUED FRI DUE TO THE LACK OF DAYTIME HEATING AND WEAK
SUBSIDENCE IN THE WAKE OF THE WAVE AXIS. CONTINUED WARM OVER THE
WEEKEND WITH DECREASING CHANCES OF PRECIP INTO LABOR DAY.

THE WELL DEVELOPED SUBTROPICAL HIGH CENTERED OVER THE MIDSECTION OF
THE COUNTRY WILL BE IN CONTROL OF OUR WEATHER THROUGH NEXT WEEK AS
IT MIGRATES SLOWLY WEST...AND THEN BACK TO THE EAST LATER IN THE
WEEK. HEIGHTS/THICKNESS WILL REMAIN ELEVATED...AND VARYING DEGREES
OF MONSOONAL MOISTURE WILL KEEP A CHANCE OF THUNDERSTORMS...MAINLY
IN THE MOUNTAINS AND DESERTS. ALONG THE COAST...SOME REDEVELOPMENT
OF THE MARINE LAYER SHOULD ALLOW AT LEAST AREAS OF MARINE STRATUS TO
BECOME REESTABLISHED OVER COASTAL AREAS...BUT WITH HIGH PRESSURE
ALOFT...LIMITED INLAND PENETRATION.

&&

.AVIATION...
281610Z...BKN MERGG LAYERS BETWEEN 10000-20000 FT MSL SPREADING
WEST-NORTHWEST ACROSS THE REGION. BETWEEN 2000-30/0100 UTC MTNS
OBSCD ABOVE 6000 FT MSL...NUMEROUS  4-6SHRA SCT 2SM +SHRA...ISOLD
EMBED TSTM WITH TOPS FL350...ALSO MOVING WEST ACROSS INLAND VALLEYS.

AFTER 30/0100 UTC...SHRA/TSTM ENDING OVER LAND AREAS BUT CONTG OVER
WATER...OTRW SCT CLDS BELOW 10000 FT MSL AND BKN-SCT CLDS BETWEEN
10000 AND 25000 FT MSL.

&&

.MARINE...
TWO SIGNIFICANT MARINE WEATHER CHANGES TODAY THROUGH SUNDAY...
FIRST CHANGE IS THE INCREASE IN SOUTH SWELL AND THE ARRIVAL OF THE
FIRST WNW SWELL OF THE LATE SUMMER. COMBINED SEAS FROM BOTH WILL BE
AROUND 5 FEET...WHICH NORMALLY IS NOT NOTEWORTHY EXCEPT FOR THE
FACT IT THAT THIS IS ABOUT TWICE AS HIGH AS WHAT SEAS HAVE BEEN FOR
THE PAST MONTH.

SECOND CHANGE IS THE THREAT OF NOCTURNAL THUNDERSTORMS TONIGHT/
FRIDAY MORNING AS THE EASTERLY WAVE MOVES ACROSS THE AREA. THE
PROBABILITY OF THESE OCCURRING IS HIGHER THAN THE MONSOON SURGE
EVENT OF LAST WEEKEND/EARLIER THIS WEEK. WITH THAT EVENT THERE WERE
THUNDERSTORMS OVER THE MEXICAN COASTAL WATERS WEST AND SOUTH OF
ENSENADA...BUT NOT FURTHER NORTH DUE TO THE TRANSPORT WINDS
REMAINING FROM SOUTHWEST OVER THE SOUTHERN CALIFORNIA COASTAL
WATERS. WITH THE FORECAST SYNOPTIC PATTERN FOR THIS EVENT...THE
TRANSPORT WINDS WOULD REMAIN OUT OF THE EAST/SOUTHEAST THROUGH
FRIDAY....AMPLE TIME FOR THE MOISTURE AND INSTABILITY TO MOVE ACROSS
THE COASTAL WATERS. ALL THAT WOULD THEN BE NEEDED IS A TRIGGER
MECHANISM. THIS COULD COME FROM AN OUTFLOW BOUNDARY MOVING FROM LAND
TOWARDS THE COAST AND COLLIDING WITH THE WANING SEA BREEZE DURING
THE EARLY EVENING HOURS...AND/OR FROM THE INTERACTION BETWEEN ANY
SUBSEQUENT OUTFLOW BOUNDARIES AND THE PREVAILING SOUTHEAST FLOW
OVERNIGHT. THIS WOULD BE A SCENARIO FOR CONTINUING THUNDERSTORM
DEVELOPMENT THROUGH THE NIGHT. PLAN TO ISSUE A MARINE WEATHER
STATEMENT BEFORE NOON WITH SIMILAR WORDING USED IN THE STATEMENT
ISSUED ON MONDAY.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...FLASH FLOOD WATCH THIS AFTERNOON
AND EVENING FOR MOUNTAINS AND DESERTS...SEE LAXFFASGX.

&&

PUBLIC...JAD
AVIATION...BALFOUR

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN DIEGO CA
1230 PM PDT THU AUG 29 2013

CAZ048-050-055-056-058-060>062-300200-
SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN
DIEGO COUNTY VALLEYS-SAN BERNARDINO COUNTY MOUNTAINS-RIVERSIDE
COUNTY MOUNTAINS-SAN DIEGO COUNTY MOUNTAINS-APPLE AND LUCERNE
VALLEYS-COACHELLA VALLEY-SAN DIEGO COUNTY DESERTS-
1230 PM PDT THU AUG 29 2013

...FLASH FLOOD WATCH IN EFFECT FROM NOON PDT TODAY THROUGH THIS
EVENING...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EXTREME
SOUTHWESTERN CALIFORNIA.

.DAY ONE...TODAY AND TONIGHT

SHOWERS AND THUNDERSTORMS WITH LOCALLY HEAVY RAIN AND FLASH FLOODING
POSSIBLE. A FLASH FLOOD WATCH IS IN EFFECT.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

SCATTERED SHOWERS AND THUNDERSTORMS FRIDAY. SMALLER CHANCE OF
AFTERNOON THUNDERSTORMS SATURDAY AND AGAIN TUESDAY AND WEDNESDAY.

.SPOTTER INFORMATION STATEMENT...

SKYWARN WEATHER ACTIVATION IS REQUESTED FOR THIS AREA.

JAD