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AREA FORECAST DISCUSSION

 
 FXUS66 KHNX 241748
 AFDHNX
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
 948 AM PST TUE NOV 24 2009
 
 
 
 .SYNOPSIS...HIGH PRESSURE DOMINATES FOR THE NEXT FEW DAYS RESULTING 
 IN MOSTLY CLEAR SKIES AND PATCHY MORNING FOG. A CHANGE IN STORE 
 LATER IN THE WEEK. 
 
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 .DISCUSSION...A RIBBON OF FOG DOWN THE MIDDLE OF THE CENTRAL AND
 SOUTHERN SAN JOAQUIN VALLEY IS GRADUALLY DISSIPATING THIS MORNING
 AND GENERALLY SUNNY SKIES WILL PREVAIL ACROSS INTERIOR CENTRAL
 CALIFORNIA TODAY. AFTERNOON HIGHS SHOULD BE SIMILAR TO
 YESTERDAY...EXCEPT IN A FEW AREAS SUCH AS MERCED AND TAFT WHICH
 REMAINED BENEATH SMALL BUT PERSISTENT CLOUD DECKS YESTERDAY. THESE
 LOCATIONS SHOULD EXPERIENCE A 5-10 DEGREE WARMUP TODAY UNDER SUNNY
 SKIES. THE FORECAST FOR TODAY LOOKS ON TRACK AND NO UPDATE IS ANTICIPATED.
 
 
 .AVIATION...
 AREAS OF MVFR CONDITIONS IN HAZE ACROSS THE SAN JOAQUIN VALLEY 
 THROUGH 03Z WEDNESDAY...BECOMING AREAS OF IFR IN MIST AFTER 03Z 
 WEDNESDAY WITH LCL LIFR IN FOG FROM 09Z TO 16Z WEDNESDAY. 
 OTHERWISE...VFR CONDITIONS WILL PREVAIL ELSEWHERE IN THE CENTRAL 
 CALIFORNIA INTERIOR THROUGH 18Z WEDNESDAY.
 
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 .AIR QUALITY ISSUES...
 ON TUESDAY NOVEMBER 24 2009...FIREPLACE/WOOD STOVE BURNING IS
 PROHIBITED IN KERN COUNTY. FURTHER INFORMATION IS AVAILABLE AT
 VALLEYAIR.ORG
 
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 .PREV DISCUSSION... /ISSUED 610 AM PST TUE NOV 24 2009/ 
 
 
 THE 00Z MODELS ARE IN GOOD AGREEMENT WITH AN UPPER-LEVEL RIDGE OVER 
 CALIFORNIA THROUGH WEDNESDAY. AN UPPER-LEVEL TROUGH WILL DEVELOP OVER
 THE GULF OF ALASKA TODAY AND DEEPEN AS IT MOVES EASTWARD WEDNESDAY. 
 THE TROUGH IS FORECAST TO BE ALONG 130W BY 00Z FRIDAY...THEN MOVE 
 INTO CALIFORNIA BY 12Z FRIDAY. THIS IS FORECAST TO BE A FAST MOVING 
 SYSTEM...WITH THE TROUGH AXIS MOVING ACROSS THE HANFORD FORECAST/ 
 WARNING AREA BETWEEN 12-18Z FRIDAY. THE GFS...ECMWF AND NAM-12 ALL 
 KEEP 850-700-MB MOISTURE NORTH OF THE CENTRAL CALIFORNIA INTERIOR 
 FRIDAY AS THE TROUGH MOVES THROUGH...SO DO NOT EXPECT ANY 
 PRECIPITATION FROM THIS SYSTEM.
 
 ALTHOUGH FRIDAY/S TROUGH WILL BE DRY OVER THE CENTRAL CALIFORNIA 
 INTERIOR...IT WILL BRING A COLD AIRMASS. THE 00Z GFS LOWERS 850-MB 
 TEMPERATURES OVER CENTRAL CALIFORNIA BY 4 C FRIDAY...AND THE 00Z 
 ECMWF BY 6 C. 1000-500-MB THICKNESSES OVER THE REGION ARE FORECAST 
 TO FALL BY AS MUCH AS 60 METERS. THE GFS MEX GUIDANCE FOR THE CENTRAL
 AND SOUTHERN SAN JOAQUIN VALLEY HAS ONLY 0-2 DEGREES COOLING FOR 
 FRIDAY...AND THIS SEEMS TOO LITTLE BASED OF 850-MB TEMPERATURE AND 
 1000-500-MB THICKNESS TRENDS. THE CURRENT FORECAST HAS 5-7 DEGREES 
 COOLING FRIDAY...AND THIS SEEMS MORE IN LINE WITH THE MODELS.
 
 THE UPPER-LEVEL TROUGH IS FORECAST TO LINGER OVER THE GREAT BASIN 
 FRIDAY NIGHT AND SATURDAY...AND THE 00Z ECMWF EVEN RETROGRESSES IT 
 BACK INTO CALIFORNIA BY 00Z SUNDAY. THIS...COMBINED WITH THE LOW- 
 LEVEL COLD POOL TRAPPED OVER THE SAN JOAQUIN VALLEY...WILL KEEP 
 TEMPERATURES COOL FOR ONE MORE DAY.
 
 AN UPPER-LEVEL EAST-PACIFIC RIDGE BEGINS BUILDING INTO CALIFORNIA 
 SUNDAY AND WILL BE OVER THE REGION MONDAY INTO NEXT TUESDAY. THIS 
 WILL ALLOW TEMPERATURES TO WARM TO A FEW DEGREES ABOVE NORMAL. MEX 
 GUIDANCE HAS COOLING NEXT TUESDAY DESPITE THE RIDGE...BUT BELIEVE 
 THIS IS THE GUIDANCE TRENDING TOWARD CLIMATOLOGY AT THE END OF THE 
 PERIOD. 
 
 
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 .HNX WATCHES/WARNINGS/ADVISORIES...
 NONE.
 &&
 
 

 
 PUBLIC...JEB
 AVN/FW...DCH
 
 WEATHER.GOV/HANFORD
 
 
 
 
 

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