AREA FORECAST DISCUSSION

 
 FXUS65 KPSR 140217 AAA
 AFDPSR
 
 AREA FORECAST DISCUSSION...UPDATED
 NATIONAL WEATHER SERVICE PHOENIX AZ
 715 PM MST MON FEB 13 2012
 
 .UPDATE...
 UPDATED AVIATION SECTION.
 
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 .SYNOPSIS...
 A STRONGER AND COLDER WEATHER DISTURBANCE WILL MOVE INTO THE REGION 
 TUESDAY. A THREAT OF SHOWERS WILL DEVELOP AREA-WIDE TUESDAY...ALONG 
 WITH MUCH COLDER TEMPERATURES. IMPROVING CONDITIONS ARE EXPECTED 
 LATE TUESDAY NIGHT AND WEDNESDAY...FOLLOWED BY ANOTHER WEATHER 
 DISTURBANCE WEDNESDAY NIGHT AND THURSDAY. A SLIGHT CHANCE OF SHOWERS 
 WILL DEVELOP ON DESERTS BY THURSDAY MORNING. MOSTLY CLEAR AND WARMER 
 WEATHER IS EXPECTED FRIDAY INTO THE WEEKEND.  
 
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 .DISCUSSION...
 TONIGHT THROUGH TUESDAY EVENING...
 THE SECOND IN A SERIES OF WEATHER SYSTEMS WAS RAPIDLY APPROACHING AZ 
 THIS AFTERNOON FROM CENTRAL CA. THIS SYSTEM IS FORECAST TO MOVE 
 BODILY THROUGH AZ TUESDAY AFTERNOON. AHEAD OF THE COLD FRONT...GUSTY 
 WINDS TO 45 MPH ARE EXPECTED IN SOUTHEAST CA THE REMAINDER OF THE 
 AFTERNOON/EVENING. A WIND ADVISORY REMAINS POSTED FOR THAT AREA 
 UNTIL MIDNIGHT. WINDS HAVE ALREADY GUSTS TO 43 MPH IN A FEW 
 LOCATIONS IN IMPERIAL COUNTY.
 
 SINCE THE CORE OF THE WEATHER SYSTEM WAS ONSHORE THIS MORNING... 
 NUMERICAL MODELS HAD A GREAT INITIAL ANALYSIS...AND FAIRLY GOOD 
 FORECAST. ALTHOUGH MASS FIELDS ON BOTH THE EUROPEAN AND GFS MODELS 
 LOOK SIMILAR...WE SLIGHTLY FAVOR THE EUROPEAN MODEL DUE TO ITS 
 SLIGHTLY WETTER SOLUTION THAN THE GFS MODEL.
 
 WEATHER BALLOON DATA THIS MORNING DIDNT SHOW A LARGE AMOUNT OF 
 MOISTURE WITH THIS SYSTEM INITIALLY...HOWEVER IT HAS BEGUN TO 
 ENTRAIN A MORE MARINE MOISTURE AS IT WORKED ITS WAY TOWARD AZ. THIS 
 WILL NOT BE A VERY WET STORM FOR OUR FORECAST AREA...SOUTHEAST CA TO 
 SOUTH CENTRAL AZ...AND STORM TOTAL PRECIP AMOUNTS SHOULD BE LESS 
 THAN ONE 0.15 OF AN INCH...WITH SLIGHTLY MORE IN THE MOUNTAINS.  
 
 THE PRECIP POTENTIAL FOR SOUTHWEST AND SOUTH CENTRAL AZ WILL COME IN 
 TWO WAVES...WITH THE COLD FRONT TUESDAY MORNING...THEN LATER AS 
 AFTERNOON INSTABILITY SHOWERS. THE AIRMASS IS VERY COLD AND SNOW 
 LEVELS SHOULD FALL MARKEDLY TUESDAY. THE SNOW LEVEL HAS THE 
 POTENTIAL TO DROP TO NEAR 3500 FT TUESDAY MORNING IN JOSHUA TREE 
 NATIONAL PARK...HOWEVER NOT MUCH PRECIP SHOULD BE REALIZED THERE.  
 BETWEEN PHOENIX AND GLOBE...IN SOUTH CENTRAL AZ...SNOW LEVELS WILL 
 FALL FROM NEAR 5500 FEET TUESDAY MORNING TO BETWEEN 4000 AND 4500 BY 
 LATE IN THE DAY. AGAIN THE SHOWERY NATURE OF THE PRECIP WILL 
 PRECLUDE ANY SIGNIFICANT ACCUMULATIONS...BUT PERHAPS 1 OR 2 INCHES 
 OF DRY SNOW COULD ACCUMULATE ABOVE 5000 FEET IN SOUTHERN GILA COUNTY.
 
 THE WEATHER DISTURBANCE WILL MOVE QUICKLY OUT OF AZ TUESDAY NIGHT 
 WITH PRECIP ENDING PERHAPS BEFORE MIDNIGHT. 
 
 WEDNESDAY AND THURSDAY...
 ANOTHER WEATHER DISTURBANCE WILL MOVE FROM JUST OFF THE WASHINGTON 
 COAST THIS EVENING...SOUTH INTO SOUTHERN CA/SOUTHWEST AZ BY 
 WEDNESDAY NIGHT AND EARLY THURSDAY. FOR NOW WE HAVE A SLIGHT CHANCE 
 OF SHOWERS IN SOUTHEAST CA BY LATE AFTERNOON WEDNESDAY...SPREADING 
 TO SOUTHWEST AND SOUTH CENTRAL AZ LATE WEDNESDAY NIGHT/THURSDAY. 
 
 FRIDAY AND SATURDAY...
 HIGH PRESSURE WILL REBUILD OVER THE REGION FOR MOSTLY CLEAR SKIES 
 AND WARMER TEMPERATURES.
 
 SUNDAY...
 ANOTHER WEATHER SYSTEM WILL MOVE INTO THE REGION SUNDAY...HOWEVER 
 FOR NOW IT APPEARS THAT IT WILL MOVE NORTH OF OUR FORECAST AREA 
 RESULTING IN GUSTY WINDS AND COOLER TEMPERATURES.
 
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 .AVIATION...SOUTHEAST CALIFORNIA...SOUTHWEST AND SOUTH CENTRAL 
 ARIZONA...INCLUDING KPHX...KIWA...KIPL AND KBLH...
 
 APPROACHING LOW PRESSURE SYSTEM...CENTERED OVER CENTRAL CALIFORNIA 
 AS OF 02Z...WILL BRING WINDY CONDITIONS TO SOUTHEAST CALIFORNIA THIS 
 EVENING WITH WESTERLY GUSTS OF 30-35 KTS. WINDS ACROSS SOUTHWEST AND 
 SOUTH-CENTRAL ARIZONA WILL BE LIGHTER...EXPECTED TO REMAIN BELOW 15 
 KNOTS THROUGH THE PERIOD OVER THE PHOENIX AREA. THE ASSOCIATED COLD 
 FRONT WILL EXIT SOUTHEAST CALIFORNIA LATE THIS EVENING AND REACH THE 
 PHOENIX AREA BY 12Z. CIGS OF 7-9 KFT MSL WILL BE COMMON OVER PHOENIX 
 AREA AHEAD OF THE FRONT. SCATTERED LIGHT SHOWERS WILL ACCOMPANY THE 
 FRONT OVER SOUTH-CENTRAL ARIZONA...ESPECIALLY EAST OF THE PHOENIX 
 AREA...WITH CIGS DOWN TO 6-8 KFT MSL. THE BEST TIME FOR ANY SHOWERS 
 OR ORGANIZED RAIN SHOULD BE IN A 09-15Z WINDOW FOR KPHX AND KIWA. 
 CIGS AND VSBYS ARE EXPECTED TO REMAIN VFR THROUGH 00Z WEDNESDAY. 
 
 AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
 
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 .FIRE WEATHER... 
 WEDNESDAY THROUGH SUNDAY... 
 COOLER TEMPERATURES AND HIGHER HUMIDITY LEVELS AREA EXPECTED AS A 
 SERIES OF LOW PRESSURE SYSTEMS MOVE THROUGH THE REGION. THE WEATHER 
 PATTERN WILL REMAIN COOL AND UNSETTLED...WITH PRECIPITATION CHANCES  
 LINGERING THROUGH THURSDAY. DRIER CONDITIONS AND A SLOW GRADUAL 
 WARMING TREND WILL TAKE PLACE ACROSS SOUTHEAST CALIFORNIA AND THE 
 SOUTHWEST DESERTS OF ARIZONA FROM FRIDAY INTO THE WEEKEND. 
 
 &&
 
 .PSR WATCHES/WARNINGS/ADVISORIES...
 
 AZ...NONE.
 
 CA...WIND ADVISORY FROM 1 PM PST TODAY TO MIDNIGHT PST TONIGHT
      CAZ030-032-033.
 
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 NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
 
 WEATHER.GOV/PHOENIX
 
 DISCUSSION...VASQUEZ   
 AVIATION...AJ
 FIRE WEATHER...MEYERS
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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