Severe Thunderstorm Warning 120, NWS Tucson, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
130 PM MST TUE SEP 9 2008

.SYNOPSIS...MOISTURE WILL INCREASE THIS WEEK IN ADVANCE OF A TROUGH
OF LOW PRESSURE MOVING DOWN THE WEST COAST. THIS WILL BRING AN
INCREASED CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS OVER THE
NEXT FEW DAYS. EXPECT COOLER DAYTIME TEMPERATURES AS MOISTURE
INCREASES.

&&

.DISCUSSION...MOISTURE SURGE EVIDENT ON WATER VAPOR AND VISIBLE
IMAGERY AS WELL AS KYUX VWP UP THE GULF THROUGH DESERTS MAINLY WEST
AND NORTHWEST OF TUCSON. WESTERLY FLOW BETWEEN THE DEVELOPING
PACIFIC COAST TROUGH AND HIGH DEPRESSED SOUTH AND EAST OF US WILL
BRING THIS INTO PLAY ACROSS THE ENTIRE AREA OVER THE NEXT FEW DAYS.
FOR TODAY...SOME MID LEVEL WARMING HAS SLOWED CONVECTIVE DEVELOPMENT
UNTIL LATER IN THE AFTERNOON ESPECIALLY FOR VALLEY LOCATIONS...WITH
EARLY EVENING BEING FAVORED. SCENARIO GOOD FOR ISOLATED OVERNIGHT
CONVECTION AS WELL.

DEEPER MOISTURE MORE WIDESPREAD WEDNESDAY. SOME SOUTHERN SPLIT IN
ENERGY AS IMPULSE DIGS INTO THE STATE THURSDAY OR SO FOR FURTHER
FOCUS TO STORMS. AFTER THAT DRY NORTHWESTERLY FLOW BEHIND EXITING
TROUGH AND AHEAD OF BUILDING WEST COAST RIDGE...BUT WE WILL HAVE TO
WATCH OUT FOR MOISTURE INPUT FROM DECAYING TROPICAL SYSTEMS. FOR NOW
GFS PULLS REMNANTS UP WELL EAST.

&&

.AVIATION...ISOLD TO SCATTERED TSRA/SHRA ACROSS ALL OF SE AZ
CONTINUING INTO TONIGHT. LIGHT DIURNALLY DRIVEN SURFACE WINDS INTO
TUESDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

WEATHER.GOV/TUCSON