Dust Storm in Arizona, August 10, 2002

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
205 PM MST SAT AUG 10 2002

.SYNOPSIS...MOISTURE REMAINS IN SOUTHEASTERN ARIZONA FOR SCATTERED
THUNDERSTORMS TODAY AND EARLY SUNDAY. HIGH PRESSURE EXTENDING FROM
WESTERN ARIZONA INTO THE EASTERN PACIFIC WILL BRING A DRIER AIR INTO
THE REGION LATE SUNDAY. THESE CHANGES WILL DECREASE THUNDERSTORM
ACTIVITY AND CAUSE TEMPERATURES TO GO ABOVE NORMAL EARLY NEXT WEEK.

.DISCUSSION...ACTIVITY SLOW TO START THIS AFTERNOON...HOWEVER
MOISTURE FIELDS ARE REMAINING IN COCHISE...GRAHAM...EASTERN PIMA AND
SANTA CRUZ COUNTIES. THE LOWER LEVEL GOES PRECIPITABLE WATER SHOWS
THAT WESTERN AND CENTRAL PIMA COUNTY HAVE DRIED OUT WHICH WILL
HINDER DEVELOPMENT THERE. SOUTHWEST NEW MEXICO IS ACTIVE TODAY AND
THESE STORMS ARE MOVING TOWARD THE ARIZONA BORDER.  EXPECT TO SEE
SOMETHING ASSOCIATED WITH THESE STORMS IN COCHISE COUNTY TONIGHT.

SINCE DRIER AIR IS GRADUALLY MOVING INTO THE SOUTHEAST PORTION OF
THE STATE FROM THE WEST AND NORTH...WILL CHANGE THE WORDING IN MOST
FORECAST ZONES FROM AN AREAL COVERAGE OF THUNDERSTORMS TO A
PROBABILITY CATEGORY. THIS CHANGE HELPS HIGHLIGHT AN INCREASED
UNCERTAINTY OF THUNDERSTORMS ACTUALLY OCCURRING. CERTAINLY NOT A
MAJOR CHANGE TO THE CURRENT FORECAST...BUT STILL NOTEWORTHY. HAVE
TWEAKED THE HIGH TEMPERATURES UP AND LOWS DOWN A BIT TO COINCIDE
WITH THIS DRIER AIR.

SEE NOTHING IN THE EXTENDED TO MAKE CHANGES AT THIS TIME.  THE HIGH
PRESSURE REMAINS NEAR CENTRAL AND SOUTHERN ARIZONA WHICH IS NOT THE
MOST FAVORED LOCATION FOR CONTINUING A MOIST ATMOSPHERE. MONDAYS
POPS ARE LOW. TUESDAY THROUGH SATURDAY WILL KEEP THE CHANCE WORDING
TO REFLECT THE UNCERTAINTY BEYOND SEVERAL DAYS THIS TIME OF YEAR.
GWS

.TWC...NONE.

AZZ019-029>035-110700-

SOUTHEAST ARIZONA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1130 AM MST SAT AUG 10 2002

.SYNOPSIS...SOME DRY AIR IS FILTERING INTO THE LOW LEVELS AND WILL
KEEP MONSOON THUNDERSTORMS CONFINED TO THE MOUNTAINS...GENERALLY
FROM TUCSON AND EAST...WITH STORMS MOVING OFF THE MOUNTAINS LATER IN
THE AFTERNOON.

.DISCUSSION...BOTH PHOENIX AND TUCSON SOUNDINGS SHOWING DRY FLOW IN
LOW LEVELS...ALTHOUGH MID LEVEL MOISTURE SEEMS ABOUT THE SAME AS
YESTERDAY. DURING THE DAY MIXING WILL KEEP THUNDERSTORMS ON THE
MOUNTAINS BUT DURING THE LATE AFTERNOON AND EVENING MID LEVEL FLOW
FROM THE EAST WILL TEND TO PUSH THE STORMS INTO THE VALLEYS.
SOUNDING LOOKS DRY MICROBURST TYPE...SO BEST CHANCE OF SEVERE WILL
BE WINDS. AS FOR HEAVY RAIN...ONLY COCHISE COUNTY LOOKS SUSPECT FOR
THAT BECAUSE OF DRY AIR. STORMS YESTERDAY WILL TEND TO SLOW INITIAL
DEVELOPMENT TODAY.  MOTION OF THE STORMS WILL BE TO THE WEST AT 10
MPH.