FXUS66 KHNX 272148
AFDFAT

INTERIOR CENTRAL CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
245 PM PDT SUN JUL 27 2003

INTERESTING PATTERN SHAPING UP BY MIDWEEK. FOR AT LEAST
THE NEXT 24 HOURS...HOWEVER...LITTLE CHANGES ARE EXPECTED
WITH GREAT BASIN HIGH ALOFT MAINTAINING A STRONG HOLD ON
OUR WEATHER. IN FACT...BETWEEN NOW AND MONDAY AFTERNOON...
THE UPPER LEVEL RIDGE WILL BUILD WESTWARD INTO CENTRAL CA
THUS STRENGTHENING THE INVERSION CAP AND MINIMIZING THE
CONVECTIVE POTENTIAL ACROSS THE CWA. AS A RESULT...LATE
AFTN TSTORMS WILL BE FEW AND FAR BETWEEN AND GENERALLY
CONFINED TO THE HIGHEST ELEVATIONS. HENCE...THE HIGHLIGHT
OF OUR WEATHER PATTERN THROUGH MONDAY WILL CONTINUE TO BE 
THE HEAT. AS UNRELENTING AS IT HAS BEEN DURING THE PAST
SEVERAL DAYS...TRIPLE DIGIT HEAT IN THE SJ VLY IS LIKELY
TO COME TO AN END BY MIDWEEK...UNFORTUNATELY BY VIRTUE OF
CLOUDS CAUSED BY A NORTHWARD INFLUX OF MONSOONAL MOISTURE
AND NOT BY ANY CLEANSING MARINE PUSHES FROM THE COAST.

FOR THE NEXT 24 TO 36 HRS...THIS STRONG RIDGE OF HIGH PRESSURE
ALOFT WILL BLOCK TROPICAL MOISTURE FROM MOVING NORTHWARD OUT OF 
BAJA. ONE EASTERLY WAVE IS FORECAST TO MOVE ACROSS SOUTHERN CA
MONDAY AFTERNOON AND NIGHT. IN THE MEANTIME...ALL OF THE MODELS
DEVELOP AN UPPER LEVEL LOW OFF THE BAJA COAST. AS IT BECOMES
MORE ORGANIZED TUESDAY...IT WILL BEGIN TO ADVECT SOME MID AND
HIGH LEVEL MOISTURE NORTHWARD FROM BAJA. AS IT ADVANCES
NORTHWARD TUESDAY...THIS MONSOONAL MOISTURE WILL PROBABLY 
INCREASE THE RISK OF CONVECTION ACROSS AT LEAST THE SOUTHERN 
PORTION OF OUR CWA. FROM TUESDAY NIGHT THROUGH WEDNESDAY...
THE UPPER LEVEL LOW WILL BE POSITIONED OFF THE SOUTHERN CA
COAST WHILE THE CENTER OF THE HIGH PRESSURE RIDGE ALOFT SITS
OVER THE GREAT BASIN. THIS WILL BE AN IDEAL SETUP TO CHANNEL A
VERY RICH SUPPLY OF MONSOONAL MOISTURE RIGHT INTO CENTRAL CA. 
DURING THIS TIME...T-STORM ACTIVITY IS LIKELY TO INCREASE
OVER THE HIGHER ELEVATIONS...AND NOT NECESSARILY BE CONFINED
TO JUST THE AFTERNOON AND EVENING HOURS. ADDITIONALLY...A SE FLOW
MAY ALSO BRING ISOLD TSTORMS INTO THE SJ VLY...ANYWHERE AND AT
ANYTIME FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. ONCE THIS
MONSOONAL MOISTURE ARRIVES...WE WILL ALL NOTICE A HUMID CHANGE
IN THE WEATHER. THE ONLY CONSOLATION WILL BE A RETURN TO MORE
SEASONABLE AFTN TEMPS BY WEDNESDAY.  DURFEE
    
FOR THE EXTENDED FORECAST PERIOD...THURSDAY THROUGH SUNDAY...
MAJORITY OF THE EXTENDED PROGS SUGGEST CENTRAL CA REMAINS 
IN A MOIST SOUTHEAST FLOW BETWEEN A HIGH AMPLITUDE RIDGE EXTENDING 
INTO THE NORTHERN ROCKIES AND AN UPPER LOW OFFSHORE NEAR 140W. THIS 
WILL KEEP ISOLATED TO SCATTERED THUNDERSTORMS GOING ACROSS THE 
ENTIRE CWFA THURSDAY AS MID/UPPER MOISTURE STREAMS INTO THE AREA 
WITH FAVORABLE 700-300 MB Q VECTOR CONVERGENCE AND MID LEVEL OMEGAS 
EXPECTED TO PREVAIL. THE PATTERN IS SLOWLY EXPECTED TO CHANGE FRIDAY 
AS AN UPPER TROUGH PUSHES INTO BC AND WEAKENS THE GREAT BASIN HIGH. 
THIS WILL TURN THE UPPER FLOW PATTERN OVER CENTRAL CA TO THE SOUTH 
WHICH WOULD KEEP THUNDERSTORMS CONFINED TO THE MOUNTAINS AND KERN 
DESERTS AND THAT ISOLATED IN COVERAGE AT THE MOST. LOW CONFIDENCE IN 
THE UPPER FLOW ACTUALLY TURNING SOUTHWEST OVER THE WEEKEND AS THIS 
DID NOT VERIFY ON THE LAST TWO OCCASIONS THAT THE PROGS EXPECTED TO 
IT OCCUR. IF THIS DOES ACTUALLY HAPPEN THEN WE SHOULD HAVE LESS 
CLOUD COVER THAN ANTICIPATED. THE ABUNDANT CLOUD COVER EXPECTED ON 
THURSDAY SHOULD KEEP MAXIMUM TEMPERATURES BELOW NORMAL AFTER A WARM 
AND MUGGY MORNING. A SLOW DRYING TREND IS EXPECTED FRIDAY THROUGH 
SUNDAY BOTH MINIMUM AND MAXIMUM TEMPERATURES SHOULD SLOWLY TREND 
TOWARD AVERAGE FOR EARLY AUGUST.  DS

.HNX...NONE.

$$