000 FXUS66 KHNX 100525 AFDHNX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA 915 PM PST THU FEB 9 2012 .SYNOPSIS... AN UPPER LEVEL HIGH PRESSURE RIDGE CONTINUES TO BE THE DOMINANT FEATURE IN THE INTERIOR CENTRAL CALIFORNIA WEATHER PATTERN. THIS HAS BROUGHT NEAR NORMAL TEMPERATURES AND CLEAR SKIES. A CHANGE IS IN STORE FOR THE REGION THIS WEEKEND WHEN WE RETURN TO COOLER TEMPERATURES AND AN UNSETTLED WEATHER PATTERN. && ...MAXIMUM TEMPS RAISED FOR FRIDAY... .DISCUSSION...TODAY WAS AN INCREDIBLY WARM DAY FOR EARLY FEBRUARY. IN FACT...MANY HIGH TEMPERATURE RECORDS FELL BY THE WAYSIDE IN THE SJ VLY. (FOR SPECIFIC DETAILS...PLEASE SEE THE SFORERHNX...SXUS76) WE CAN THANK AN UPPER LEVEL RIDGE OF HIGH PRESSURE FOR THE SPRINGLIKE WARMTH THE PAST COUPLE OF DAYS. THIS RIDGE WILL HANG ON LONG ENOUGH TO BRING US ONE MORE DAY OF EXCEPTIONALLY MILD WEATHER. BASED ON CURRENT 24-HR TRENDS...MAX TEMPS WERE BUMPED UP A BIT FOR FRIDAY IN THE EVENING FORECAST UPDATE. HIGH TEMP RECORDS FOR FEBRUARY 10TH DO NOT LOOK LIKE THEY WILL BE CHALLENGED AS THEY ARE AT LEAST A FEW DEGREES HIGHER THAN TODAY. AS MUCH AS WE LOVE THE SUN-FILLED DAYS AND BALMY AFTERNOONS...THE CRIES FOR WET WEATHER ARE GETTING LOUDER. FORTUNATELY...THERE FINALLY IS PROMISE THAT MUCH OF THE CENTRAL CA INTERIOR WILL RECEIVE PRECIP IN THE DAYS TO COME. THE MODELS FORECAST AT LEAST TWO STORM SYSTEMS TO MOVE INTO CENTRAL CA BETWEEN SATURDAY AND TUESDAY. THE FIRST STORM WILL HERALD A CHANGE TO MUCH COOLER WEATHER THIS WEEKEND WITH A COLD FRONTAL PASSAGE OCCURRING SATURDAY MORNING. SHOWERS WITH THIS STORM SYSTEM WILL BE RATHER LIGHT AND MOSTLY CONFINED TO THE HIGHER TERRAIN. HOWEVER...IN THE POST FRONTAL ENVIRONMENT...ISOLATED THUNDERSTORMS WITH SMALL HAIL COULD POP UP IN THE SJ VLY SATURDAY AFTERNOON. THIS SYSTEM WILL EXIT RATHER QUICKLY INTO THE GREAT BASIN SATURDAY NIGHT AND BE FOLLOWED BY SHORT WAVE RIDGING ALOFT SUNDAY. THE NEXT STORM SYSTEM WILL BE A LITTLE STRONGER...COLDER...AND WETTER WHEN IT ARRIVES MONDAY AND IT WILL ALSO THREATEN TO BRING ISOLATED THUNDERSTORMS WITH SMALL HAIL INTO THE SJ VLY MONDAY AFTERNOON AND EVENING AS THE COLDEST PART OF THE STORM MOVES OVER CENTRAL CA. OTHERWISE...CONVECTION WILL BE AT A PREMIUM WITH THIS STORM. SNOW LEVELS WILL LOWER TO ABOUT 3500-4500 FEET BY MONDAY EVENING AND THERE MIGHT EVEN BE A LITTLE ICE AND SNOW OVER THE GRAPEVINE BY MONDAY NIGHT. MEANWHILE...AT LEAST A FEW INCHES OF SNOW WILL ACCUMULATE OVER THE HIGHER ELEVATIONS OF THE SIERRA. ADDITIONALLY...THESE TWO STORMS WILL GENERATE BRISK WINDS BELOW THE MOUNTAIN PASSES OF KERN COUNTY SATURDAY AND AGAIN MONDAY. THE STORM SYSTEM EARLY NEXT WEEK COULD BRING WIND SPEEDS TO ADVISORY LEVELS IN THIS REGION MONDAY AFTERNOON AND NIGHT. THE MODELS DISAGREE ON EXACTLY WHERE STORM #2 ENDS UP AFTER MONDAY NIGHT. THE GFS MOVES THIS FEATURE INTO THE FOUR CORNERS REGION AND BRINGS AT LEAST ONE UPPER LEVEL DISTURBANCE IN THE NORTHWEST FLOW ALOFT INTO THE CWA TUESDAY AFTERNOON AND EVENING. THE ECM FORECASTS THE STORM SYSTEM TO STALL OUT OVER CENTRAL CA THROUGH TUESDAY. WHATEVER THE CASE...IT LOOKS AS THOUGH OUR WEATHER WILL REMAIN UNSETTLED AND QUITE COOL THROUGH TUESDAY. THE MODELS FINALLY COME INTO BETTER AGREEMENT THEREAFTER AND BUILD AN EPAC RIDGE INTO CENTRAL CA DURING THE MID TO LATER PART OF NEXT WEEK. && .PREV DISCUSSION... /ISSUED 215 PM PST THU FEB 9 2012/ DISCUSSION...A RIDGE OF HIGH PRESSURE OVER THE REGION IS PROVIDING MOSTLY CLEAR SKIES AND ABOVE NORMAL TEMPERATURES ACROSS THE CENTRAL CALIFORNIA INTERIOR TODAY. THE RIDGE WILL BEGIN TO WEAKEN AND BE PUSHED EASTWARD FRIDAY AFTERNOON AS A SHORTWAVE TROUGH BEGINS TO AFFECT NORTHERN CALIFORNIA. THIS TROUGH WILL MOVE INTO CENTRAL CALIFORNIA EARLY SATURDAY AND WILL BRING A CHANCE OF PRECIPITATION TO THE SIERRA NEVADA WITH A SLIGHT CHANCE OF LIGHT SHOWERS ELSEWHERE SATURDAY. MANY AREAS IN THE SAN JOAQUIN VALLEY WILL ONLY EXPERIENCE SPRINKLES. THIS SYSTEM WILL ALSO BRING COOLER AIR INTO THE REGION...WHICH WILL BRING TEMPERATURES BACK TO NEAR NORMAL. THERE WILL BE WEAK SHORTWAVE RIDGING ON SUNDAY FOR A DRY DAY BEFORE ANOTHER TROUGH DROPS INTO CALIFORNIA SUNDAY NIGHT AND MONDAY. THIS SYSTEM LOOKS TO BE WETTER THAN THE SATURDAY SYSTEM...BUT STILL NOT A BIG RAINMAKER. THE 12Z MODELS HAVE SLOWED THIS SYSTEM A LITTLE BIT...HOLDING OFF ANY PRECIPITATION UNTIL EARLY MONDAY MORNING FOR CENTRAL CALIFORNIA. THUS...HAVE LOWERED POPS SLIGHTLY FOR SUNDAY NIGHT BUT HAVE NOT REMOVED THEM COMPLETELY AS THERE IS A POSSIBILITY THAT PRECIPITATION COULD ARRIVE LATE SUNDAY NIGHT. THE 12Z RUNS OF THE ECMWF AND GFS ARE IN BETTER AGREEMENT WITH THE TRACK OF THE LOW...MOVING INLAND ACROSS CENTRAL CALIFORNIA MONDAY. BUT THE ECMWF IS SLOWER TO MOVE THE SYSTEM OUT ON TUESDAY WHILE THE GFS SHIFTS THE MAIN TROUGH EAST EARLY TUESDAY AND DROPS A SECONDARY SHORTWAVE DOWN THE EAST SIDE OF THE SIERRA. HAVE LEFT SLIGHT CHANCE POPS OVER THE MOUNTAIN AND DESERT AREAS TUESDAY. THE TROUGH THAT THE GFS WAS ADVERTISING YESTERDAY FOR THE WEDNESDAY TIME FRAME HAS BEEN REPLACED WITH A RIDGE OF HIGH PRESSURE WITH TODAYS MODEL RUNS. BOTH THE GFS AND ECMWF ARE IN AGREEMENT WITH THIS...SO WEDNESDAY AND THURSDAY LOOK TO BE DRY DAYS WITH TEMPERATURES NEAR NORMAL. && .AVIATION... PATCHY FOG FORMING IN THE SAN JOAQUIN VALLEY DURING THE EARLY MORNING WITH AREAS OF MVFR VISIBILITIES IN MIST AND PATCHES OF IFR IN FOG BETWEEN 10Z-17Z. OTHERWISE VFR CONDITIONS ELSEWHERE ACROSS THE CENTRAL CA INTERIOR THRU 06Z SATURDAY. && .AIR QUALITY ISSUES... ON FRIDAY FEBRUARY 10 2012... FIREPLACE/WOOD STOVE BURNING IS PROHIBITED IN FRESNO COUNTY. FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG && .HNX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ PUBLIC...DURFEE PREVIOUS DISCUSSION...BEAN AVN/FW...DUDLEY SYNOPSIS...ANDERSEN WEATHER.GOV/HANFORD