Debris Flow in California, May 14, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
912 AM PDT SUN MAY 14 2006

.UPDATE...SKIES ARE CURRENTLY SUNNY OVER THE AREA, HOWEVER
SATELLITE IMAGERY SHOWS A LARGE AREA OF MID AND HIGH LEVEL
MOISTURE TAKING AIM ON CENTRAL CALIFORNIA. EMBEDDED IN THIS
FEATURE IS A SHORTWAVE AND VORTICITY CENTER, NOW ABOUT 500 MILES
SOUTHWEST OF POINT CONCEPTION. INFRARED SATELLITE SHOWS QUITE A
BIT OF CONVECTION AND IF THIS SYSTEM HOLDS TOGETHER, THE THREAT OF
SHOWERS AND THUNDERSTORMS WILL BEGIN TONIGHT. LATEST FORECAST
MODELS AGREE THAT THE SHORTWAVE AND VORT CENTER WILL MOVE INTO THE
BAY AREA LATER TONIGHT AND EARLY MONDAY MORNING. OF INTEREST IS
THE NAM12 MODEL STABILITY PROGS FOR MONDAY, WHICH DEPICT QUITE A
BIT OF INSTABILITY FOR FRESNO (CAPE TO 1600 J/KG AND LIFTED INDEX
OF -5) DURING THE LATE MORNING AND AFTERNOON. THIS MAY BE WAY OVER
DONE HOWEVER EVEN THE GFS MODEL SHOWS MORNING LIFTED INDICES AT
-1. PER COORDINATION WITH WFOS LAS VEGAS AND SACRAMENTO, WILL
INCLUDE SLIGHT CHANCE POPS FOR TONIGHT AND MONDAY. OF INTEREST
CONCERNING FLOODING POTENTAL ALONG THE MERCED RIVER IN YOSEMITE,
OVERNIGHT STAGE REACHED 9.96 FEET AT POHONO BRIDGE (OFFICIAL FLOOD
STAGE IS 10.0 FEET). WITH TODAYS WARMER TEMPERATURES AND THE
INCOMING CLOUD COVER FOR TONIGHT WHICH WILL KEEP LOW TEMPERATURES
UP, THE RIVER WILL MOST LIKELY GO ABOVE FLOOD STAGE TONIGHT. IF
ANY RAIN OCCURS, THE STAGE COULD GO CONSIDERABLY HIGHER. ALL IN
ALL WILL MAKE GRID CHANGES TO INCLUDE THE CONVECTIVE THREAT FOR
TONIGHT AND MONDAY.

&&

.PREV DISCUSSION... (ISSUED 330 AM PDT SUN MAY 14 2006)

SHORT TERM...STRONG UPPER RIDGE WILL BUILD OVER THE REGION THE NEXT
FEW DAYS. MODELS SHOW THICKNESS RISES OF ABOUT 40 METERS TODAY ALONG
WITH 2 DEGS/C WARMING AT H85...SO A FEW DEGS WARMER ALL AREAS TODAY
FROM YESTERDAY. FOR MON AND TUES...CONTINUED WARMING AS OMEGA
PATTERN CONTINUES TO STRENGTHEN. SOME VALLEY AND DESERT LOCALES
COULD SEE THE FIRST TRIPLE DIGITS OF THE SEASON...ESPECIALLY TUES.
SAT PIX SHOW SOME MID AND HIGH CLOUDS BEING ADVECTED NORTHWARD
TOWARD THE CA COAST THIS MORNING. CROSS SECTIONS SHOW THIS MOISTURE
REACHING CENTRAL CA THIS EVENING...SO HAVE GONE PARTLY CLOUDY
TONITE AND MON MORNING. OTHERWISE SKIES SHOULD BE MOSTLY CLEAR. ALL
IN ALL...A TYPICAL SUMMER PATTERN...ONLY THIS IS MID MAY.

LONG TERM...FOR TUESDAY NIGHT THROUGH SATURDAY...MEDIUM RANGE MODEL
SOLUTIONS STILL LEANING TOWARD DEVELOPING A STRONG RIDGE PATTERN AT
THE START OF THE PERIOD. WILL THEREFORE RAISE TEMPERATURES ACROSS
THE DISTRICT IN RESPONSE TO THE BUILDING RIDGE AND PLACE TEMPERATURE
VALUES CLOSER TO MODEL GUIDANCE. THIS CHANGE WILL LEAD TOWARD
AFTERNOON MAX TEMP/S NEAR THE CENTURY MARK BY WEDNESDAY AND INTO
THURSDAY. MODELS STILL INDICATE THAT THE TROF OVER THE EASTERN
PACIFIC...THAT MAY HELP TO AMPLIFY THE RIDGE...WILL SHIFT EAST AND
CLOSER TO THE WEST COAST BY SATURDAY. THIS WILL LEAD TO A WEAK
COOLING TREND ALLOWING TEMPERATURES TO RETURN BACK TOWARD SEASONAL
NORMS. YET...WILL KEEP TEMPERATURES JUST SLIGHTLY ABOVE GUIDANCE
THROUGH THE PERIOD AS HEIGHT AND THICKNESS FALLS WILL BE MINIMAL.
THESE WARM TEMPERATURES WILL KEEP THE CONCERN OF HIGH...FAST AND
COLD RUNNING RIVERS AND STREAMS DUE TO MELTING SNOW AT A HEIGHTEN
STATE OF CAUTION.

AVIATION...VFR CONDITIONS CAN BE EXPECTED THROUGH 12Z MONDAY.
FOR SPECIFIC DETAILS...PLEASE REFER TO TAFS FOR KMCE...KFAT AND
KBFL.

&&

.HNX WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH WEDNESDAY MORNING FOR CAZ096.

&&

DUDLEY/BINGHAM/MOLINA