Area Forecast Discussion
Issued by NWS San Diego, CA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
000
FXUS66 KSGX 030406
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
906 PM PDT MON MAY 2 2016

.SYNOPSIS...
DRY AND SLIGHTLY WARMER ON TUESDAY UNDER WEAK HIGH PRESSURE ALOFT.
COOLER ON WEDNESDAY WITH A DEEPENING MARINE LAYER AS A STORM SYSTEM
DEVELOPS AND APPROACHES THE NORTHERN CALIFORNIA COAST. THE STORM
WILL DROP SOUTHEAST OVER SOCAL ON FRIDAY...THEN MOVE SLOWLY OFF TO
THE NORTHEAST. GUSTY WESTERLY WINDS WILL DEVELOP OVER THE MOUNTAINS
AND DESERTS ON THURSDAY WITH SCATTERED SHOWERS AND POSSIBLE
THUNDERSTORMS BREAKING OUT. THE UNSETTLED CONDITIONS WILL CONTINUE
THROUGH SATURDAY...FOLLOWED BY WARMER AND DRIER WEATHER NEXT WEEK.

&&

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

CONVECTIVE CLOUDS EARLIER IN THE DAY HAD MOSTLY DISSIPATED BY 9 PM
PDT...BUT IR SATELLITE IMAGERY SHOWED SOME AREAS OF LOW CLOUDS ALONG
THE COAST. THE 00Z MIRAMAR SOUNDING HAD A 5 DEGREE C INVERSION BASED
NEAR 1850 FT. WEST WINDS AROUND 10 KT BELOW THE INVERSION BECAME
EASTERLY AROUND 10 KT ABOVE TO 10K FT. SURFACE PRESSURE GRADIENTS
WERE 2-3 MBS OFFSHORE FROM NV...AND 3-5 MBS ONSHORE TO THE LOWER
DESERTS RESULTING IN MOSTLY LIGHT WINDS.

THERE WAS A CONSIDERABLE AMOUNT OF HAZE THIS EVENING AND DEWPOINTS
HAVE CLIMBED INTO THE MID 50S ALONG THE COASTAL STRIP...SO SOME FOG
WILL LIKELY DEVELOP INLAND BEFORE MARINE CLOUDS BECOME MORE
EXTENSIVE. WEAK EASTERLY FLOW IN THE MID-LEVELS SHOULD HELP
THICKNESS CLIMB TOMORROW UNDER FAIR SKIES. SO AWAY FROM THE
IMMEDIATE COAST...IT WILL BE WARMER.

TUESDAY WILL BE THE WARMEST DAY INLAND...THEN A COOLING TREND SETS
IN AS ONSHORE FLOW STRENGTHENS AND THE MARINE LAYER BUILDS WEDNESDAY
INTO THURSDAY. THERE IS HIGH CONFIDENCE FOR THE DEVELOPMENT OF A
LARGE CUT-OFF LOW PRESSURE CENTER OFF THE NOCAL COAST WED NIGHT...
WITH A TRACK SE...OVER SOCAL BY FRI. AS CYCLONIC FLOW INCREASES OVER
THE REGION AND SURFACE PRESSURE FALLS OVER THE INTERIOR...THE
WESTERLY WINDS WILL BEGIN TO HOWL ONCE AGAIN OVER THE MTS/DESERTS.
THE PATTERN SUGGESTS AT LEAST ADVISORY STRENGTH WINDS IN MANY AREAS.

SINCE THIS STORM IS COMING FROM THE NORTH...MOISTURE WILL BE A BIT
MORE LIMITED (PW 0.65-0.80 INCH)...SO WIDESPREAD HEAVY PRECIP IS NOT
EXPECTED. HOWEVER...IT WILL BE SUFFICIENT FOR ISOLATED HEAVY
RAINFALL EVENTS STARTING SOMETIME ON THU. THE ACTIVITY SHOULD BE
SCATTERED AND DRIVEN BY IMPULSES OF ENERGY SWIRLING AROUND THE LARGE
AREA OF LOW PRESSURE ALOFT. THUNDERSTORMS ARE EXPECTED AT TIMES DUE
TO THE INSTABILITY AND COLD AIR ALOFT THROUGH SATURDAY. THE SNOW
LEVEL WILL START OUT AROUND 7000 FEET..THEN DROP CLOSER TO 6000
FEET...AND BRIEFLY LOWER IN THUNDERSTORMS. THIS UNSETTLED SPRINGTIME
PATTERN SUGGESTS WATERSPOUTS WILL BE POSSIBLE AS WELL.

TEMPERATURES WILL DROP THROUGH FRIDAY...THE COLDEST DAY OF THE WEEK
WHEN TEMPERATURES WILL NOT REACH THE 70S...EXCEPT IN THE LOWER
DESERTS. DRY WITH GRADUAL WARMING SUNDAY THROUGH TUESDAY AS THE
STORM LOSES ITS GRIP ON THE REGION.

&&

.AVIATION...

030320Z...PATCHY STRATUS WITH BASES 1000-1500 FT MSL WILL CONTINUE
TO DEVELOP ALONG THE COAST AND SPREAD AND SPREAD 20-25 MI INLAND BY
12Z. LOW CONFIDENCE IN TIMING OF ONSET AT KSAN AND KSNA. LOCAL VIS
OF 3-5SM POSSIBLE WHERE STRATUS NEARS HIGHER TERRAIN IN THE VALLEYS.
STRATUS CLEARING 17-19Z...RETURNING TO THE COASTAL AIRPORTS AFTER
04/02Z WITH BASES NEAR 1500 FT MSL.

MOUNTAINS/DESERTS...MOSTLY CLEAR WITH UNRESTRICTED VIS THROUGH TUE
EVENING.

&&

.MARINE...
830 PM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH WEDNESDAY.
A STORM SYSTEM WILL BRING WIND GUSTS AROUND 25 KT AND CHOPPY SEAS
THURSDAY NIGHT INTO FRIDAY...AS WELL AS SHOWERS AND POSSIBLE
THUNDERSTORMS ON FRIDAY.

&&

.SKYWARN...
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.

&&

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

$$

PUBLIC...JAD
AVIATION/MARINE...SS



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.