Dust Storm Warning 6, NWS Tucson, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
345 PM MST MON JUL 30 2007

.SYNOPSIS...AN UPPER LEVEL LOW OVER NORTHWEST CHIHUAHUA WILL
GRADUALLY DRIFT WEST OVER THE NEXT SEVERAL DAYS...KEEPING THE REGION
IN AN ACTIVE MONSOON PATTERN THROUGH MOST OF THE WEEK.

&&

.DISCUSSION...SOME DEBRIS CLOUD WITH A LITTLE FLAT CU FIELD
ENHANCEMENT INHIBITING HEATING THIS MORNING. DECENT LOOKING 12Z KTUS
SOUNDING WITH PRECIPITABLE WATER AT 1.61 AND NICELY UNSTABLE WITH
TEMPERATURE RECOVERY AT LOWER LEVELS AND A DEGREE OF COOLING FROM H5
TO H6. ONCE WE GET SOME HEATING AND HIT LOWER 90S MOUNTAINS WERE
EARLY TO BUILD. ONLY INHIBITION SO FAR IS CIRRUS HAS BLOWN OFF IN
DIRECTION OF PATH OF STORMS AND GENERALLY OVER VALLEYS. ULTIMATELY
OUTFLOWS WILL HAVE NO TROUBLE SUPPORTING CONVECTION IN THE
VALLEYS...BUT FOR SOME LOCATIONS IT MAY BE IN THE EVENING HOURS.

WEAK MID LEVEL DIRECTIONAL SHEAR COMBINED WITH SLOW STORM EASTERLY
STORM MOVEMENT (BUT LIKELY INCREASING A LITTLE THROUGH THE DAY) HAS
MADE FOR RATHER CONGESTED INITIAL THUNDERSTORM DEVELOPMENT.
SUBSEQUENT STRONG OUTFLOWS SHOULD HELP TO BREAK THINGS OUT AS STORMS
PROPAGATE ACROSS VALLEY BY EARLY IN THE AFTERNOON. WET MICROBURST
AND LOCALLY HEAVY RAINFALL THE MAIN CONCERN. ACTIVITY PUSHING IN
FROM NEW MEXICO WILL HAVE TO BE MONITORED CLOSELY AS THE ATMOSPHERE
IS PRIMED TO SUPPORT CONVECTION OVERNIGHT.

NICE LOW ACROSS CHIHUAHUA SOUTH OF WEST TEXAS HELPING TO STRENGTHEN
UPPER LEVEL DIFFLUENT FIELD...AND SHOULD BECOME MORE OF A PLAYER
OVER THE NEXT 72 HOURS. NICE H7 THETA-E RIDGE NOSING FROM CHIHUAHUA
INTO ARIZONA AS WELL.

&&

.AVIATION...A MORE TYPICAL THUNDERSTORM PATTERN CAN BE EXPECTED
TODAY WITH THUNDERSTORMS DEVELOPING IN THE MOUNTAINS AND SKY ISLANDS
BY NOON AND IMPACTING VALLEY LOCATIONS IN THE AFTERNOON AND EVENING.
STRONG WINDS AND HEAVY DOWNPOURS MAY AFFECT TAF SITES TODAY.
AVIATION DISCUSSION NOT UPDATED FOR TAF AND TWEB AMENDMENTS.

&&

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

&&

WEATHER.GOV/TUCSON