Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 201034
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
334 AM PDT WED AUG 20 2014

.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE THROUGH SOUTHERN CALIFORNIA
THROUGH THURSDAY AND BRING CHANCES FOR SHOWERS AND THUNDERSTORMS
TO MUCH OF THE REGION. TEMPERATURES WILL BE BELOW NORMAL WITH
NIGHT AND MORNING LOW CLOUDS IN COASTAL AND VALLEY AREAS. FAIR
AND WARMER WEATHER WILL RETURN FRIDAY AS THE LOW PRESSURE EXITS
TO THE EAST...WITH FEWER LOW CLOUDS AND ONLY MINOR DAY TO DAY
FLUCTUATIONS IN TEMPERATURES OVER THE WEEKEND. FURTHER WARMING IS
POSSIBLE EARLY NEXT WEEK TO NEAR NORMAL LEVELS.

&&

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

THE UPPER LOW PRESSURE IS CENTERED NEAR THE CHANNEL ISLANDS EARLY
THIS MORNING. THIS FEATURE WILL BRIEFLY CUTOFF THROUGH THURSDAY
EVENING BEFORE BEING EJECTED EAST TOWARDS THE 4 CORNERS FRIDAY AND
OPENING UP. HI-RES MODELS IN GOOD AGREEMENT WITH THE UPPER LOW
FEATURE WITH A NARROW TAP OF SUBTROPICAL MOISTURE CONTINUING
THROUGH THURSDAY MORNING AND GENERATING SCATTERED CONVECTION AT
TIMES. THE THREAT OF CONVECTION WILL CONTINUE THIS MORNING ACROSS
THE COASTAL SECTOR AND THROUGH THE INLAND EMPIRE. WE EXPECT THE
AREA OF CONVECTION FOCUS TO TRANSITION TO THE INLAND MOUNTAINS AND
DESERTS LATER THIS AFTERNOON AND EVENING WITH DIURNAL HEATING
ALTHOUGH AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT THROUGH
THURSDAY MORNING ACROSS THE COASTAL REGION TOO.

THE CONVECTION THIS MORNING HAS BEEN PERSISTENT SINCE ABOUT
MIDNIGHT AND ALONG A TRAINING BAND FROM THE NEARSHORE WATERS NEAR
SAN CLEMENTE ISLAND TO NEAR OCEANSIDE HARBOR...AND INLAND TO NEAR
ONYX PEAK. HI-RES CONVECTIVE PARAMETERS INDICATE SURFACE BASED
INSTABILITY WILL BE FAIRLY IMPRESSIVE ACROSS THE INLAND MOUNTAINS
THIS AFTERNOON WITH CAPE VALUES REACHING 1000+ J/KG. RESIDUAL
MOISTURE PRIMARILY FOR INLAND AREAS WILL CONTINUE THE THREAT OF
CONVECTION THROUGH THURSDAY MORNING BEFORE OUR REGION IS PLACED ON
THE BACKSIDE OF THE UPPER LOW.

ONSHORE FLOW...ALBEIT NOT AS STRONG...WILL CONTINUE THROUGH THE
WEEKEND. THIS WILL CONTINUE TO BRING SLIGHTLY BELOW NORMAL
TEMPERATURES ALONG THE COAST AND ACROSS THE COASTAL VALLEYS TOO.
THE HIGH PRESSURE ZONE WILL BUILD WEST FROM THE DESERT SOUTHWEST
AND BRING A MINOR WARMUP EARLY NEXT WEEK. TEMPERATURES WILL WARM
UP BUT ARE NOT EXPECTED TO EXCEED LATE AUGUST NORMALS THROUGH
EARLY NEXT WEEK.

&&

.AVIATION...
201000Z...PATCHY STRATUS...WITH BASES FROM 2100-2500 FT MSL AND TOPS
TO 3100 FT MSL...WILL CONTINUE ALONG PORTIONS OF THE COAST AND
COASTAL VALLEYS THIS MORNING. SCATTERED THUNDERSTORMS MOVING
NORTHEAST...STRETCHING FROM THE COASTAL WATERS NEAR KCRQ INLAND TO
THE MOUNTAINS NEAR KRIV...WILL CONTINUE SLOWLY SOUTHWARD THIS
MORNING. LIGHTNING...SMALL HAIL AND GUSTY WINDS WILL BE POSSIBLE
NEAR STORMS. THUNDERSTORMS CHANCES WILL CONTINUE THROUGH THURSDAY
MORNING ACROSS THE REGION. PATCHY STRATUS WILL CLEAR TOWARDS THE
COAST LATE THIS MORNING...THEN REDEVELOP ALONG THE COAST TONIGHT
WITH SLIGHTLY LOWER TOPS AND BASES.

&&

.MARINE...
300 AM...SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO MOVE
NORTHEAST ACROSS THE COASTAL WATERS THROUGH LATE THIS MORNING.
CLOUD-TO-WATER LIGHTNING...GUSTY WINDS...SMALL HAIL...ROUGH SEAS AND
ISOLATED WATERSPOUTS MAY ACCOMPANY STORMS. THE POSSIBILITY OF
SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THURSDAY MORNING. A
MARINE WEATHER STATEMENT REMAINS IN EFFECT FOR THUNDERSTORMS OVER
THE COASTAL WATERS THROUGH THURSDAY MORNING.


&&

.SKYWARN...
SKYWARN ACTIVATION MAY BE REQUESTED LATER TODAY DUE TO
THUNDERSTORMS. WEATHER SPOTTERS ARE ENCOURAGED TO REPORT ANY
OBSERVED SIGNIFICANT WEATHER CONDITIONS.


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...BROTHERTON
AVIATION/MARINE...JJT






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