Severe Thunderstorm Warning 9, NWS Phoenix, AZ

AZZ020>028-CAZ030>033-100545-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
320 PM MST TUE JUL 9 2002

.SYNOPSIS...
STRONG HIGH PRESSURE ALOFT OVER THE CENTRAL AND SOUTHERN ROCKIES IS
EXPECTED TO DEVELOP A DEEP EASTERLY FLOW ACROSS SOUTHWEST ARIZONA
AND SOUTHEAST CALIFORNIA THIS WEEK. THIS WILL IMPORT MOISTURE FROM
THE EAST...PROVIDING A GOOD START TO THE SUMMER THUNDERSTORM SEASON.
THIS INCREASE IN MOISTURE WILL LEAD TO SCATTERED THUNDERSTORMS OVER
SOUTH CENTRAL ARIZONA TONIGHT. IN ADDITION...A SERIES OF MINOR LOW
PRESSURE SYSTEMS WILL BE MOVING WESTWARD OVER NORTHERN MEXICO...
INCREASING THUNDERSTORM ACTIVITY THERE AND THUS FEEDING ADDITIONAL
MOISTURE INTO THIS AREA. LOOK FOR INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS...WITH SOME BLOWING DUST ON THE LOWER DESERTS...AS THE
WEEK PROGRESSES.

.DISCUSSION...
APPEARS THAT THE MONSOON IS ABOUT READY TO MAKE ITS OFFICIAL
APPEARANCE...AS LOW LEVEL MOISTURE VALUES ARE UP SUBSTANTIALLY TODAY
AND CONVECTION IS FIRING NICELY OVER ERN AZ...AND HEADED OUR WAY. A
VERY STRONG HIGH PRESSURE RIDGE CONTINUES OVER THE WESTERN STATES
WITH A 6000M HIGH CENTER NOW OVER SRN NV. THIS GIVING A RATHER
STRONG DEEP ELY FLOW TO MOST OF THE STATE...WITH MEAN WINDS IN THE
0-6KM LAYER FROM THE EAST AT 20KT. THIS ELY FLOW ADVECTING IN QUITE
A BIT OF MOISTURE...PWAT VALUES OVER SRN AZ NOW RUNNING OVER 1.5
INCHES OVER MUCH OF THE AREA...AS SEEN BOTH GOES PWAT IMAGERY AND
THE TUS/PHX RAOBS. AT 3 PM SURFACE DEWPOINTS OVER MOST OF THE SCNTRL
DESERTS WERE IN THE 50S. TEMPS AGAIN HAVE CLIMBED NICELY...AIDED IN
PART BY THE UNREASONABLY HOT LOW TEMPERATURES SEEN ACROSS THE
DESERTS THIS MORNING. SOME SPOTS REACHING TO AROUND 110 DEGREES
AGAIN. PHX...BTW...TIED THE ALL TIME RECORD HIGH MINIMUM OF 93
DEGREES THIS MORNING. IN ANY CASE...SCT STORMS ARE FIRING OVER THE
ERN MOUNTAINS AND ARE MOVING WEST...SHOULD MOVE INTO OUR ERN ZONES
TONIGHT. CONVECTION IS AIDED BY A STRONG INVERTED TROF THAT WILL
MOVE SWWD OUT OF NM AND INTO ECNTRL AZ OVERNIGHT...THEN ACROSS OUR
DESERTS WED. THIS DISTURBANCE WILL LIKLEY CAUSE CONVECTION TO
CONTINUE WELL PAST MIDNIGHT AND POSSIBLY INTO THE MORNING HOURS.
THUS WILL CONTINUE TO FORECAST A SLIGHT CHANCE FOR MORNING SHOWERS
OR STORMS OVER MOST OF THE AZ LOWER DESERTS. AS FOR WED AND
BEYOND...BASIC FLOW PATTERN NOT FORECAST TO CHANGE MUCH THRU
SAT...WITH THE STRONG UPPER HIGH REMAINING TO OUR NE...A MODERATE
ELY FLOW ACROSS THE CWA...GIVING A CHANCE FOR AFTN/EVE STORMS TO
DEVELOP AND MOVE OFF THE HIGHER TERRAIN AND OVER THE LOWER DESERTS
EACH DAY. ONCE THE MOISTURE GETS IN PLACE...BY WED...IT WILL NOT
REALLY LEAVE ANYTIME SOON SO THUS THE STANDARD MONSOON FORECAST WILL
HOLD THRU THE WEEKEND. LATEST MRF/AVN CONTINUE TO SUGGEST THAT THERE
WILL BE A GOOD SUBTROPICAL TAP DEVELOPING SUNDAY INTO MIDDLE OF NEXT
WEEK...WITH THE FLOW BECOMING MORE SELY AND ABLE TO TAP MOISTURE TO
OUR SOUTH ASSOCIATED WITH SOME SORT OF TROPICAL
DISTURBANCE/DEPRESSION. THUS THESE PROGS REALLY UP THE RH OVER OUR
WESTERN ZONES SUN THRU TUE...AND LOWER TEMPS SOMEWHAT IN RESPONSE.
WILL KEEP THE BROADBRUSHED FORECAST GOING FOR SAT THRU TUE...BUT
MENTION A TEMP FALLOFF OF A FEW DEGREES AFTER SATURDAY.  11

.PSR...NONE.