Flash Flood Warning 9, NWS San Diego, CA

EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
230 PM PDT SUN JUL 11 1999

                          ...SYNOPSIS...

MOISTURE IN EASTERLY FLOW ALOFT WILL CONTINUE TO CAUSE SCATTERED
AFTERNOON AND EVENING SHOWERS OR THUNDERSTORMS IN THE MOUNTAINS AND
DESERTS. SOME SHOWERS COULD DRIFT OFF THE MOUNTAINS OVER THE INLAND
VALLEYS AND COASTAL AREAS. OTHERWISE...HIGH PRESSURE ALOFT WILL
KEEP THE WEATHER FAIR. CONTINUED HOT INLAND.

                         ...DISCUSSION...

MAINLY DEBRIS CLOUDS OVER MUCH OF SW SBD COUNTY AND A FEW OVER W
RIV AND SNA MOUNTAIN THIS AM. THUNDERSTORMS FORMED OVER NRN
MOUNTAINS AND SPREAD S THIS AFTERNOON. PATCHY STRATUS NEAR S COAST
THIS AM...OTHERWISE CLEAR SKIES. 12Z NKX SOUNDING REMAINS FAIRLY
UNSTABLE AND MOIST NEAR 700 MB. WEAK ELY FLOW AT MID LEVELS AND
STRONGER SSE FLOW ALOFT. WEAK OFFSHORE GRADIENTS FROM N AND WEAK
ONSHORE TO E WITH LESS THAN 3 MB SAN-IPL.

12Z MODELS ONCE AGAIN DIFFER ON DETAILS...AS USUAL. TO SOME DEGREE
OR ANOTHER...ALL MODELS INDICATE AN ELY WAVE MOVING PAST TO N THIS
AFTERNOON/EVE. THIS SHOULD HELP FOCUS CONVECTIVE ACTIVITY INTO NRN
ZONES. CANNOT RULE OUT SOME STORMS DRIFTING INTO THE INLAND EMPIRE
THIS AFTERNOON AND OTHER INLAND VALLEYS MON/TUE AFTERNOON. STILL
PLENTY OF PRECIPITABLE WATER AND SLOW MOVING THUNDERSTORMS COULD
CAUSE SOME LOCALIZED FLOODING...ESPECIALLY E SLOPES AND RIDGES OF
NRN MOUNTAINS. NOT READY FOR FLASH FLOOD WATCH YET BUT WILL HAVE TO
MONITOR CLOSELY. THERMAL LOW MOVES CLOSER TO COAST MON WITH WEAKER
ONSHORE OR EVEN WEAK OFFSHORE GRADIENTS. THIS WILL LIMIT ANY EARLY
MORNING COASTAL STRATUS TO PATCHY AT BEST. MAX TEMPS WILL BE HIGHLY
DEPENDENT ON RH/CLOUDS COVER IN MOUNTAINS AND DESERTS AND COULD GET
SLIGHT COOLING NEXT COUPLE DAYS...ESPECIALLY IN DESERTS. SHOULD
HAVE SOME WARMING W OF MOUNTAINS. HOWEVER...WILL STILL GET SEA
BREEZE TO THERMAL LOW INLAND EACH AFTERNOON THAT WILL HELP MODERATE
COASTAL TEMPS. SOME INDICATIONS OF STRONGER ELY FLOW AT MID AND HI
LEVELS WITH INCREASING RH LATE MON INTO TUE. SO EXPECT CONTINUED
MOUNTAIN/DESERTS THUNDERSTORMS AND POSSIBILITY OF SOME GETTING W OF
MOUNTAINS...EVEN TO COAST.

LONGER RANGE PROGS CONTINUE TO INDICATE TROF MOVING PAST TO N WITH
DRIER SW FLOW ALOFT TOWARD THE SECOND HALF OF WEEK.

SAN 0000

.SAN...NONE.

ATKIN

CAZ042-043-048>050-055>058-060>062-121100-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
1100 AM PDT SUN JUL 11 1999

...VERY WARM AND HUMID CONDITIONS FOR EXTREME SOUTHWESTERN
CALIFORNIA INTO TUESDAY...

...MONSOONAL MOISTURE WILL CONTINUE TO CAUSE THUNDERSTORMS IN THE
MOUNTAINS AND DESERTS...

A VERY WARM AND HUMID AIR MASS WILL LINGER ACROSS EXTREME
SOUTHWESTERN CALIFORNIA INTO TUESDAY.  THIS WILL CONTINUE TO BRING
AFTERNOON AND EVENING THUNDERSTORMS TO THE MOUNTAINS AND DESERTS.

HIGH TEMPERATURES WILL BE IN THE 80S NEAR THE COAST AND IN THE
MOUNTAINS...90S TO NEAR 105 IN THE INLAND VALLEYS...AND 103 TO 108
IN THE DESERTS. OVERNIGHT LOWS WILL REMAIN BALMY...WITH MINIMUM
READINGS GENERALLY BETWEEN 65 AND 70 DEGREES ACROSS COASTAL AND
VALLEY AREAS. THE COMBINATION OF HEAT AND FAIRLY HIGH HUMIDITY WILL
MAKE DAYTIME ACTIVITIES MORE STRESSFUL.

SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS
AND DESERTS EACH DAY. A FEW SHOWERS COULD EVEN DRIFT WEST OVER THE
INLAND VALLEYS. DUE TO THE SLOW MOVEMENT OF THE THUNDERSTORMS AND
MOIST ATMOSPHERE...THE MAIN THREAT FROM THESE STORMS WILL BE THE
POTENTIAL FOR FLASH FLOODING IN THE MOUNTAINS AND DESERTS. PEOPLE
IN THESE AREAS SHOULD STAY INFORMED ON CURRENT WEATHER CONDITIONS
IN CASE A FLASH FLOOD WATCH OR WARNING IS ISSUED.

ATKIN