EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
AFDSAN 915 PM PST TUE MAR 5 2002
.SYNOPSIS...A PACIFIC SYSTEM WILL MOVE THROUGH THE AREA WEDNESDAY
NIGHT THROUGH EARLY FRIDAY AND BRING SHOWERS. MOST PRECIPITATION
AMOUNTS BE BETWEEN 1/4 AND 1/2 INCH...BUT SOME AREAS WILL RECEIVE
MORE...ESPECIALLY IN THE FOOTHILLS. A FEW INCHES OF SNOW ARE
POSSIBLE OVER THE HIGHER MOUNTAINS. OCCASIONAL GUSTY WINDS WILL
OCCUR OVER THE MOUNTAINS AND DESERTS THROUGH FRIDAY. ANOTHER SYSTEM
WILL BRING A CHANCE OF RAIN MONDAY.
.DISCUSSION...WE FINALLY HAVE A JET AROUND 30 DEG W OVER THE E
PACIFIC...SO THAT CERTAINLY LOOKS FAVORABLE FOR PRECIP WITH THIS
COMING SYSTEM. THIS SYSTEM IS SORT OF A DUEL-VORT-MAX SYSTEM NOW
EXTENDING FROM ABOUT 34N/137W BACK TO 38N/150W. 00Z MSO HAS THE
FRONT VORT MAX FAIRLY-WELL INITIALIZED...AND 00Z AVN IS OK WITH THE
BACK VORT MAX...THOUGH MSO IS PREFERRED OVERALL DUE TO ITS BETTER
RESOLUTION...AND THE BACK VORT MAX IS IN ITS DOMAIN FOR A LARGE PART
OF ITS TRACK TO OUR AREA. ANYWAY...THE FIRST VORT MAX SHOULD NOT
PRODUCE MUCH RAINFALL FOR OUR AREA AS THE DYNAMICS WILL BE WELL TO
OUR NORTH. THUS...JUST SOME LIGHT SHOWERS WILL OCCUR WEDNESDAY
NIGHT...POSSIBLY STARTING VERY LATE WED AFTERNOON NW. THE MAIN
PRECIP WILL OCCUR THU INTO THU NIGHT AS THE 2ND AND STRONGER VORT
MAX APPROACHES. THIS WILL BE SOMEWHAT ELONGATED NE-SW...AND MOISTURE
WILL BE SUFFICIENT IN THE LOW LAYERS. WITH THE COLDER AIR MOVING IN
BEHIND THAT 1ST VORT MAX...WE MAY EVEN BE HELPED BY SOME
INSTABILITY. EVEN THE MSO...WHICH HAS BEEN THE DRIER MODEL...IS
INDICATING A STORM-TOTAL PRECIP OF GENERALLY 1/4-1/2 INCH WEST OF
THE MTNS...WITH AROUND AN INCH OVER SOME FOOTHILLS UP NORTH.
THUS...IN THE UPDATE...I WILL RAISE THE POPS FOR THU/THU NIGHT.
IN THE MEANTIME...ACARS INDICATES THE INVERSION IS SOMEWHERE AROUND
1000-1200 FEET WITH ANOTHER INVERSION POSSIBLY TRYING TO FORM AROUND
3000 FEET. WE COULD GET SOME FOG EARLY...BUT THE MARINE LAYER SHOULD
DEEPEN RAPIDLY OVERNIGHT SO THAT MOSTLY JUST LOW CLOUDS WOULD BE
EXPECTED LATE.
MRF/ECM BOTH HAVE ANOTHER SYSTEM FOR SUN NIGHT/MON FOR ANOTHER
CHANCE OF PRECIP. WE SEEM TO BE GETTING INTO MORE OF A PROGRESSIVE
W-E PATTERN...AND IF THE JET STAYS FAR ENOUGH SOUTH...WE COULD SEE
MORE CHANCES OF PRECIP IN THE COMING WEEK OR TWO AFTER THAT.
A ZONE UPDATE WILL BE ISSUED SHORTLY.
.SAN...NONE.
MAXWELL