Severe Thunderstorm Warning 20, NWS Sacramento, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
915 AM PDT TUE JUL 22 2003

ANOTHER HOT DAY IN STORE FOR NORCAL. SAC SHOULD SEE ITS 7TH STRAIGHT
DAY OF 100+. MORNING RAOB AND ARB SOUNDING SHOW LITTLE CHANGE TO
SLIGHTLY WARMER WHERE IT COUNTS. ONSHORE PGRADS ARE SLIGHTLY
STRONGER BUT PULL UP THE VALLEY AND INLAND IS NIL. H85 TEMPS OF 27
TO 30C FROM SOUTHWEST TO NORTHEAST ARE A TAD HIGHER THAN YESTERDAY.
TEMPS NEAR 112F AT REDDING POSSIBLE...WHILE SLIGHTLY LOWER H85 TEMPS
AND WEAK ONGOING ONSHORE (12KT FAIRFIELD). CURRENTLY MARINE LAYER
STANDS AT NEAR 1200 FEET FROM KOAK TO MONTEREY. DEPTH SHOULD LOWER A
LITTLE WITH THE BUILDING UPPER RIDGE OVERHEAD. OTHER ISSUE THIS
AFTERNOON AGAIN EVOLVES AROUND THE CONVECTIVE POTENTIAL. STRONG
UPPER RIDGE OVER NEVADA WILL CONTINUE TO SLIGHTLY INCH WESTWARD AND
THIS RESULTS IN THE STEERING FLOW TO BACK TO THE SOUTHEAST. BUFKIT
SOUNDINGS SHOW LOW LEVEL CONVECTIVE INHIBITION (HIGH LFC) CONTINUING
TODAY BUT WITH BETTER SUPPORT FOR LOW LEVEL CONVERGENCE AND WEAK PVA
LATER TODAY...WE EXPECT THUNDERSTORM DEVELOP TO BE BETTER IN OUR
AREA THAN YESTERDAY BUT MAINLY IN THE SIERRA NEVADA.

THE AIR MASS IS ALREADY CONDITIONALLY UNSTABLE AND MOIST (KREV 0.85
PW). MODELS CONTINUE TO ADVECT HIGHER PRECIPITABLE WATER OVER NORCAL
LATER TONIGHT AND INTO WEDNESDAY (1.20 TO 1.50 INCHES). THIS IS
ASSOCIATED WITH AN INVERTED TROF THAT IS PROGGED TO TRACK TOWARDS
MONTEREY WEDNESDAY MORNING AND A VORT EXTENSION OVER THE SIERRA
NEVADA AT THE SAME TIME. THIS RESULTS IN INCREASING OMEGA OVERNIGHT
AND INTO WEDNESDAY (STRONGEST ALONG THE COAST)...THE DESTABILIZATION
NEEDED FOR NOCTURNAL SHOWERS AND THUNDERSTORMS. VERY MOIST AIR WILL
RESULT IN ALTOCUMULUS CASTELLANUS ON WEDNESDAY AND ANVIL DEBRIS.
THIS MAY AFFECT TEMPS AS WELL AS THE POSSIBLE INCREASE TO THE MARINE
LAYER/ONSHORE FLOW ON WEDNESDAY...EVEN THOUGH H85 TEMPS ONLY DROP
ABOUT 1 TO 2C. ENERGY THAT MOVES ALONG THE CA CENTRAL COAST RETURNS
AS AN OPEN WAVE ON THE GFS WEDNESDAY NIGHT. WITH A LARGE AREA OF
HIGH PW OVER NORCAL THIS WOULD LEAD TO ANOTHER ELEVATED THUNDERSTORM
AND SHOWER EVENT...AND POSSIBLY MORE ORGANIZED. ETA AND GFS CONTINUE
TO DIFFER WITH THE STRENGTH OF THIS FEATURE SO WE WILL WAIT FOR NEW
12Z GFS RUN BEFORE MAKING ADDITIONS TO THE GRIDS. THIS WILL ALSO
FACTOR INTO A STRONGER DELTA PUSH WEDNESDAY NIGHT TO FINALLY DROP
MIN TEMPS BACK INTO THE 60S FOR MANY LOCALES AND KEEP TEMPS IN THE
90S ON THURSDAY. STEERING FLOW BEGINS TO VEER TO THE SOUTHWEST
THURSDAY SHUNTING THUNDERSTORM DEVELOPING TO THE CREST AND FAR
NORTH. COOLING TREND AND DECREASING CONVECTION WILL TREND INTO
SATURDAY.

.STO...NONE.

TARDY

CAZ013>019-063-064-066>069-231400-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SACRAMENTO CA
620 AM PDT TUE JUL 22 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR INTERIOR NORTHERN CALIFORNIA.

.DAY ONE...TODAY

THERE IS A SLIGHT CHANCE OF THUNDERSTORMS OVER THE MOUNTAINS THIS
AFTERNOON...AND OVER THE ENTIRE REGION TONIGHT...OTHERWISE NO
HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...

ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS MAINLY THE HIGHER TERRAIN
ON WEDNESDAY AND THURSDAY...OTHERWISE NO HAZARDOUS WEATHER IS
EXPECTED AT THIS TIME.

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS TO THEIR LOCAL NATIONAL WEATHER SERVICE.

THE LATEST WEATHER INFORMATION IS AVAILABLE ON THE INTERNET
AT (LOWER CASE): HTTP://WWW.WRH.NOAA.GOV/SACRAMENTO