000
FXUS65 KPSR 192335 AAA
AFDPSR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
435 PM MST SAT JUL 19 2008
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION
.UPDATE...
UPDATED AVIATION DISCUSSION
&&
.SYNOPSIS...
MOISTURE IS INCREASING OVER OUR AREA IN A CLOCKWISE FLOW FROM THE
EAST AND SOUTH AROUND HIGH PRESSURE ALOFT THAT HAS MOVED TO COLORADO.
THIS WILL RESULT IN A SIGNIFICANT INCREASE IN THE CHANCE OF SHOWERS
AND THUNDERSTORMS...SOME WITH LOCALLY HEAVY RAIN...TONIGHT AND
SUNDAY. STRONG GUSTY WINDS ARE ALSO POSSIBLE TONIGHT. IT WILL BE
COOLER AND MORE HUMID SUNDAY. AT LEAST A SLIGHT CHANCE OF MAINLY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS IS EXPECTED THIS
COMING WEEK WITH A RECOVERY OF TEMPERATURES TUESDAY.
&&
.DISCUSSION...
THE EXPECTED SURGE OF COOLER AND MUCH MORE HUMID GULF OF CALIFORNIA
AIR WAS RESULTING IN GUSTY WINDS FROM THE SOUTHEAST AND SOUTH UP THE
COLORADO RIVER VALLEY AND INTO SOUTHEAST CALIFORNIA TODAY. THIS
RESULTED IN MUCH MORE HUMIDITY ACROSS OUR ENTIRE AREA TODAY.
THE STRONG HIGH PRESSURE SYSTEM ALOFT THAT WAS RESPONSIBLE FOR THE
NEAR EXCESSIVE HEAT YESTERDAY WILL GENERALLY BE OVER COLORADO
TONIGHT AND SUNDAY. THIS HAS ALREADY RESULTED IN A SIGNIFICANT
AMOUNT OF MOISTURE FROM THE EAST AS SEEN BY THE CLOUDS ON THE
VISIBLE SATELLITE IMAGERY TODAY. THIS WILL ALSO AID IN BRINGING AN
ABUNDANT AMOUNT OF MOISTURE OVER OVER AREA THROUGH TONIGHT AND
SUNDAY.
THE INCREASING MOISTURE AND LOW PRESSURE SYSTEMS IN THE FLOW FROM
THE EAST AND SOUTH WILL BRING A SIGNIFICANT INCREASE IN THE CHANCE
OF SHOWERS AND THUNDERSTORMS FROM EAST TO WEST ACROSS THE AREA
TONIGHT AND SUNDAY WITH LOCALLY HEAVY RAIN. STRONG GUSTY WINDS ARE
ALSO POSSIBLE TONIGHT.
THE SHOWERS AND THUNDERSTORMS OVER THE HIGHER TERRAIN SURROUNDING
THE GREATER PHOENIX AREA ARE EXPECTED TO DEVELOP FROM THE
NORTHEAST...EAST AND SOUTHEAST INTO THE GREATER PHOENIX AREA TONIGHT.
THE SHOWERS AND THUNDERSTORMS WILL RESULT IN SIGNIFICANTLY COOLER
WEATHER SUNDAY WITH HIGH TEMPERATURES ONLY NEAR 100 IN THE SOUTHWEST
ARIZONA AND SOUTHEAST CALIFORNIA DESERT AREAS INCLUDING YUMA...
EL CENTRO...AND IMPERIAL...AND IN THE MID TO UPPER 90S IN THE
SOUTH-CENTRAL DESERT AREAS INCLUDING THE GREATER PHOENIX AREA.
HAVE ISSUED ANOTHER SPECIAL WEATHER STATEMENT...AS WE WILL HAVE TO
BE ALERT FOR URBAN AND SMALL STREAM FLOODING WHICH IS LIKELY IN SOME
LOCATIONS FROM TONIGHT THROUGH SUNDAY INTO SUNDAY NIGHT ALONG WITH A
POSSIBILITY OF FLASH FLOODING.
THE CHANCE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO LINGER AT
LEAST THROUGH MONDAY WITH LITTLE TEMPERATURE CHANGE...THEN POSSIBLY
DECREASING SOMEWHAT TUESDAY WITH A RECOVERY OF TEMPERATURES AT THAT
TIME.
EXTENDED...MODELS IN GENERALLY GOOD AGREEMENT THAT THE RIDGE WILL
REMAIN ANCHORED NEAR THE FOUR CORNERS. PERSISTENT EASTERLY FLOW WILL
NECESSITATE SLIGHT CHANCE POPS FOR MUCH OF THE AZ COUNTIES THROUGH
THE WEEK. FURTHER ALOFT...AN INVERTED TROUGH CURRENTLY LOCATED
ACROSS SOUTHERN TX MAY ENHANCE RAIN CHANCES MIDWEEK. TEMPS EXPECTED
TO REMAIN NEAR OR SLIGHTLY BELOW NORMAL THROUGH THE PERIOD.
&&
.AVIATION...
KPHX/KIWA AND SURROUNDING AIRFIELDS...
LATEST THINKING BASED ON CURRENT OBSERVATIONS...TRENDS...AND MODEL
GUIDANCE IS THAT TSTMS WILL NOT DEVELOP ACROSS THE PHX AREA UNTIL
ROUGHLY 04Z THIS EVENING...THOUGH TCU/CB WILL AFFECT AIR TRAFFIC
ROUTES THIS AFTERNOON - MAINLY TO THE N AND E. INCREASING THREAT FOR
SIGNIFICANT TSTM ACTIVITY SOMEWHERE OVER PHX THIS EVENING...BUT WILL
HOLD OF ON TEMPO/PREDOMINANT MENTION IN TAFS OF TS FOR NOW AS MUCH
OF WHAT HAPPENS TONIGHT WILL BE DICTATED BY HOW THE AFTERNOON
UNFOLDS. REGARDLESS OF WHETHER OR NOT A TS DIRECTLY HITS AN
AIRFIELD...THERE WILL BE PLENTY OF DEBRIS SHOWERS/CLOUDS PERSISTING
INTO SUNDAY MORNING.
BY LATE MORNING SUNDAY...AROUND 16-18Z...SIGNIFICANT MOISTURE
INCREASE WILL LIKELY PRODUCE LOWER CLOUD DECKS...WITH SCATTERED CIGS
NEAR 5K FEET AND FEW/SCT DECKS A BIT LOWER THAN THAT. HAVE MENTIONED
VCTS AFTER 18Z IN THE KPHX/KIWA TAFS...BUT WILL NOT MENTION
PROB30/TEMPO AS CONFIDENCE IS LOW IN THE ABILITY TO TIME EXACTLY
WHEN STORMS MAY AFFECT THE AIRFIELDS.
KNYL/KBLH/KIPL AND SURROUNDING AIRFIELDS...
STRONG SLY WINDS EXPECTED THROUGH TODAY INTO TOMORROW. AT THIS TIME
APPEARS THE THE JUXTAPOSITION OF TSTM INGREDIENTS WILL BE EAST OF
THIS AREA. MAY SEE SOME TSTMS/SHWRS EEK TOWARD KBLH/KYUM LATE
TONIGHT/SUNDAY MORNING. DUE TO SIGNFICANT MOISTURE INCREASE
EXPECTED...HAVE LOWERED CIGS TO AROUND 10K FEET WITH SCATTERED DECKS
NEAR 6K FEET AFT 12Z...AND ADDED VCSH/VCTS TO THE AREA TAFS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SIGNIFICANT MOISTURE INCREASE OVER THE WEEKEND WILL CONTINUE A DAILY
THREAT FOR SHOWERS AND THUNDERSTORMS...SOME WITH HEAVY
RAINFALL...THROUGH THE MIDDLE OF NEXT WEEK. NEAR TO SLIGHTLY BELOW
AVERAGE AFTERNOON HIGH TEMPERATURES...ALONG WITH MILD OVERNIGHT
LOWS...CAN BE EXPECTED THROUGH THE MIDDLE PART OF NEXT WEEK.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
DISCUSSION...ELLIS/HIRSCH
AVIATION...CB
FIRE WEATHER...WANEK
