EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
AFDSAN 840 PM PDT WED MAY 10 2000
...SYNOPSIS...
A TROUGH OF LOW PRESSURE ALONG THE WEST COAST WILL MOVE INLAND
THURSDAY WITH ANOTHER APPROACHING FROM THE PACIFIC ON SUNDAY AND
MONDAY. WINDS WILL DECREASE IN THE MOUNTAINS AND DESERTS WITH A SLOW
WARMING TREND THROUGH SATURDAY.
...DISCUSSION...
EARLY EVENING ACARS SOUNDINGS SHOW THE MARINE INVERSION CONTINUING
TO ERODE FM THE NW IN RESPONSE TO LWR LVL COLD ADVECTION. THE MARINE
INVERSION IS NOW GONE AT BUR...BUT REMAINS NR 3000 FT FM LGB S.
COAMPS AND MM5 BOTH SHOW A SMALL CSTL EDDY DEVELOPING OVERNIGHT OFF
THE S CST...THEN DISSIPATING QUICKLY THU MORNING AS NW FLOW DEVELOPS
ACROSS ALL OF THE SRN CA CSTL WTRS. COAMPS TIME-HEIGHT CROSS
SECTIONS FOR NFG AND NZY SHOW THE MARINE LYR ALG THE S CST DEEPENING
OVERNIGHT WITH CD ADVECTION FINALLY ERODING ALL OF THE MARINE
INVERSION AT NFG BY 12Z AND AT NZY (SAN) BY 15Z. THUS...WL KP LOW
CLOUDS OVERNIGHT OVR SRN CSTL SXNS...REMOVE FOG WORDING DUE TO THE
DEPTH OF THE MARINE LYR...AND CLR ANY REMAIN CSTL LOW CLOUDS QUICKLY
THU MORNING. OTHERWISE NO CHANGES TO THE CURRENT PACKAGE.
IN THE DESERTS...WINDS AT PSP HAVE GUSTED TO 44 MPH AND TO AROUND 40
MPH AT THERMAL DURG THE LATE AFTERNOON AND EARLY EVENING HOURS. FLOW
NORMAL TO THE SAN JACINTO MTNS AND AN INVERSION NR RDG TOP LVL AS
SHOWN IN AN ACARS SOUNDING FM PSP AT 0230Z ARE BOTH FAVORABLE FOR
MTN WAVE CONDITIONS IN THE COACHELLA VLY AS HAS BEEN EXPERIENCED THE
PAST FEW HOURS. WINDS SHOULD GRADUALLY DECR AND BECOME MORE
LOCALIZED IN THE COACHELLA VLY OVERNIGHT.
EXTENDED...THE NEW (12Z) ECMWF IS NRLY IDENTICAL TO THE 12Z AVN IN
THE PLACEMENT OF THE UPR LOW OFF THE W CST AT 12Z SAT WITH BOTH W OF
THE POSITION OF THE PREVIOUS RUN OF THE AVN/MRF AT THAT TIME. THE
ECWMF MOVES THE CTNR OF THE CLOSED LOW TO A POSITION OFF THE NRN CA
CST 12Z MON...JUST W OF SFO 12Z TUE...AND NR POINT CONCEPTION 12Z
WED. THE CURRENT EXTENDED FORECAST LOOKS REASONABLE...BUT MIGHT BE A
LTL FAST IN DEEPENING THE MARINE LYR SUN IF THE SLOWER ECMWF IS
CORRECT.
SAN 0000
.SAN...NONE.
MARTIN