000
FXUS65 KPSR 150402
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
900 PM MST SUN MAR 14 2010
.SYNOPSIS...
STRONG HIGH PRESSURE ALOFT FROM THE PACIFIC WILL RESULT IN MUCH
WARMER WEATHER MONDAY...TUESDAY...AND WEDNESDAY. THE FIRST 80 DEGREE
TEMPERATURE OF THE YEAR IN PHOENIX IS EXPECTED TUESDAY OR WEDNESDAY
WITH HIGH TEMPERATURES RISING WELL INTO THE 80S ACROSS THE DESERT
AREAS THE REST OF THE WEEK. EXCEPT FOR PARTLY CLOUDY SKIES IN
SOUTHERN GILA COUNTY TONIGHT...MOSTLY CLEAR NIGHTS AND SUNNY DAYS ARE
ANTICIPATED THIS WEEK. SOMEWHAT BREEZY WEATHER FROM THE NORTHEAST AND
EAST IS EXPECTED IN SOUTH-CENTRAL AND SOUTHWEST ARIZONA INCLUDING THE
GREATER PHOENIX AREA MONDAY...AND ESPECIALLY TUESDAY AND WEDNESDAY.
THE SPRING OR VERNAL EQUINOX OCCURS THIS SATURDAY AT 1032 AM MST.
&&
.DISCUSSION...
UPPER LOW THAT PASSED BY TO OUR NORTH EARLIER TODAY HAS NOW MOVED
EAST INTO NEW MEXICO...WITH THE LOW CENTER HAVING PASSED THRU FAR
NERN AZ/FOUR CORNERS AREA. WE ARE NOW BEHIND THE LOW AND UNDER
RATHER DRY SUBSIDENT NWLY FLOW ALOFT. IR IMAGERY AT 8 PM SHOWED
CLEAR SKIES ACROSS ALL BUT ERN ZONE 24 WHERE A FEW MID CLOUDS WERE
ROTATING AROUND THE BACK OF THE LOW AND SKIRTING OUR FORECAST AREA
BOUNDARY. NO PRECIP HAS OCCURRED WITH THESE CLOUDS. AIRMASS THAT
FILTERED INTO OUR CWA BEHIND THE LOW WAS COOLER...WITNESS THE HIGH
OF JUST 66 AT PHOENIX TODAY COMPARED TO YESTERDAYS READING OF 72.
AIRMASS IS ALSO ON THE DRY SIDE...BUT NOT BONE DRY AT THE SURFACE AS
DEWPOINTS OVER THE LOWER DESERT AT 8 PM RANGED FROM MID 20S TO MID
30S.
FOR THE REST OF TONIGHT...EXPECT GENLY CLEAR SKIES OVER THE
AREA...WITH POSSIBLY SOME VERY THIN HIGH CLOUDS SPREADING INTO THE
WESTERN CWA DURING THE MORNING MONDAY. AS SURFACE HIGH PRESSURE
BUILDS TO OUR NORTH...LOW LEVEL GRADIENTS WILL TIGHTEN AND THIS MAY
CAUSE LOCAL BREEZINESS FROM THE NORTHEAST ACROSS SOUTH-CENTRAL AZ
OVERNIGHT...WITH OCCASIONAL NORTH BREEZES DOWN THE LOWER CO RIVER AS
WELL. CURRENT FORECASTS LOOK TO BE IN GOOD SHAPE AND NO UPDATES ARE
NEEDED AT THIS TIME.
.EXCERPTS FROM PREVIOUS DISCUSSION...
A LOW PRESSURE SYSTEM THAT WAS OVER NORTHWEST NEW MEXICO THIS
AFTERNOON WILL MOVE SOUTH OVER SOUTHWEST NEW MEXICO BY EARLY MONDAY
MORNING. THIS SYSTEM WAS RESPONSIBLE FOR BRINGING THE BREEZY WEATHER
WITH MUCH DRIER AND SOMEWHAT COOLER AIR INTO OUR AREA TODAY. THERE
IS ONLY ENOUGH MOISTURE IN THE COUNTER-CLOCKWISE FLOW AROUND THE LOW
PRESSURE SYSTEM FOR PARTLY CLOUDY SKIES OVER SOUTHERN GILA COUNTY
TONIGHT...OTHERWISE MOSTLY CLEAR NIGHTS ARE FORECAST TONIGHT THROUGH
THIS WEEK.
SPRING FEVER WEATHER IS ON ITS WAY...
STRONG HIGH PRESSURE ALOFT WAS CENTERED OVER THE SUBTROPICAL PACIFIC
WEST OF BAJA CALIFORNIA NEAR 130 DEGREES WEST LONGITUDE THIS
AFTERNOON. THIS STRONG HIGH PRESSURE SYSTEM WILL MOVE EAST AND
EXPAND NORTHEAST OVER THE SOUTHWESTERN UNITED STATES...WITH MUCH
WARMER WEATHER MONDAY AND SIGNIFICANT WARMING CONTINUING TUESDAY AND
WEDNESDAY.
HIGHS ARE EXPECTED TO RISE INTO THE LOWER 80S TUESDAY AND MID 80S
WEDNESDAY IN THE SOUTH-CENTRAL DESERT AREAS INCLUDING THE GREATER
PHOENIX AREA...AS WELL AS SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA
INCLUDING YUMA...EL CENTRO...AND IMPERIAL WITH TEMPERATURES ONLY
LOWERING BACK SLIGHTLY THE LATTER PART OF THE WEEK. ALTHOUGH THESE
TEMPERATURES ARE ABOVE AVERAGE FOR MID MARCH...THEY HAVE COMMONLY
OCCURRED ON SEVERAL DAYS DURING THE MONTH OF MARCH IN MANY PREVIOUS
YEARS.
THE FIRST 80 DEGREE TEMPERATURE OF THE YEAR IN PHOENIX IS EXPECTED
TUESDAY OR WEDNESDAY.
STRONG SURFACE HIGH PRESSURE WILL BUILD OVER UTAH MONDAY...EXPAND
FROM UTAH SOUTHEAST ACROSS NEW MEXICO TUESDAY...AND CONTINUE FROM
UTAH TO NEW MEXICO WEDNESDAY. THIS IS EXPECTED TO RESULT IN SOMEWHAT
BREEZY WEATHER FROM THE NORTHEAST AND EAST IN SOUTH-CENTRAL AND
SOUTHWEST ARIZONA INCLUDING THE GREATER PHOENIX AREA MONDAY...AND
ESPECIALLY TUESDAY AND WEDNESDAY.
THE SPRING OR VERNAL EQUINOX OCCURS THIS SATURDAY AT 1032 AM MST/PDT.
&&
.AVIATION...
AN UPPER LOW CENTERED NEAR THE 4 CORNERS AS OF 21Z WILL SLOWLY MOVE
SOUTHEASTWARD. CLOUDINESS ASSOCIATED WITH IT WILL REMAIN OVER THE
HIGHER TERRAIN OF EASTERN ARIZONA...MAINLY NEAR THE NEW MEXICO
BORDER. NORTHERLY SURFACE WINDS OF 10-15 KTS...GUSTING 20-25
KNOTS...OVER SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA WILL WEAKEN
CONSIDERABLY AFTER 02Z. WEAKER WESTERLY WINDS WILL CONTINUE OVER
SOUTH-CENTRAL ARIZONA...INCLUDING THE PHOENIX AREA...THROUGH 03Z
BEFORE SHIFTING TO NORTHEASTERLY DIRECTIONS AS A TIGHT NORTHEASTERLY
ORIENTED GRADIENT DEVELOPS. EXPECT SPEEDS TO REMAIN BELOW 10 KTS
OVERNIGHT AND INTO MONDAY MORNING AT THE PHOENIX AREA TAF SITES BUT
SOME FOOTHILL LOCATIONS IN THE PHOENIX AREA MAY EXPERIENCE
OCCASIONAL GUSTS OF 20-25 KTS. ABOVE THE SURFACE...SPEEDS OF 20-25
KNOTS WITHIN 1-2 KFT AGL WILL DEVELOP AFTER 06Z ACROSS MUCH OF THE
FORECAST AREA. HOWEVER...EXPECT CONDITIONS TO REMAIN BELOW LOW LEVEL
WIND SHEAR CRITERIA FOR TAFS. EXPECT NORTH AND NORTHEAST DIRECTIONS
TO PREVAIL ACROSS THE FORECAST AREA DURING THE DAY MONDAY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
LOCALLY BREEZY CONDITIONS CAN BE EXPECTED TUESDAY AND WEDNESDAY...
MAINLY OVER SOUTH-CENTRAL ARIZONA...WITH LOCALLY WINDY CONDITIONS AT
THE RIDGETOPS. THIS IS DUE TO STRONG HIGH PRESSURE BUILDING OVER THE
WEST. OVERALL THIS WILL LEAD TO MUCH WARMER TEMPERATURES DURING THE
FIRST HALF OF THE WEEK WITH A MODEST COOLING TREND DURING THE LATTER
HALF OF THE WEEK AS THE RIDGE WEAKENS AND A TROUGH PASSES THROUGH
THE WESTERN STATES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...CB/ELLIS
AVIATION...AJ
FIRE WEATHER...AJ
