Tornado in Arizona, September 16, 2001

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
230 AM MST SUN SEP 16 2001

.SYNOPSIS...SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS MUCH OF
NORTHERN ARIZONA TODAY AND MONDAY AS ABUNDANT MOISTURE REMAINS
ACROSS THE AREA. BY TUESDAY...A DRIER WESTERLY FLOW WILL DEVELOP
OVER THE STATE...WITH DRY WEATHER EXPECTED THROUGH THE REMAINDER OF
THE WEEK.

.DISCUSSION...WESTERLIES GENERALLY STRENGTHEN OVER THE NEXT THREE
DAYS AS A COOLER AIR MASS MOVES INTO THE NORTHWEST CORNER OF THE
UNITED STATES. THE STRONGER WESTERLIES SHOULD LEAD TO GRADUAL DRYING
OF THE BOUNDARY LAYER. FOR TODAY...QUITE A BIT OF MOISTURE AROUND
FOR SCATTERED SHOWERS AND THUNDERSTORMS. WILL SEE TRAINING BEHAVIOR
OF STORM CELLS ONCE AGAIN WITH LOCAL RAINFALL AMOUNTS OF AS MUCH AS
3 INCHES. ON MONDAY FURTHER DRYING TAKES PLACE BUT STILL THINK THERE
WILL BE SCATTERED STORMS OVER THE MOGOLLON RIM AND THE EAST AND
NORTHEAST PORTIONS OF ARIZONA. DRY WESTERLY FLOW CONTINUES ON
TUESDAY WITH FURTHER DRYING. STORMS SHOULD COME TO AN END OVER THE
WEST BUT ISOLATED STORMS WILL BE AROUND OVER THE EAST. LESS AND LESS
CLOUD COVER EACH DAY WITH NOT MUCH CHANGE IN TEMPERATURES. LOCALLY
BREEZY ON MONDAY AS LOW-LEVEL GRADIENTS STRENGTHEN.

IN THE EXTENDED...ARIZONA WILL BE LOCATED BETWEEN THE SUBTROPICAL
RIDGE TO THE SOUTH AND STRONG WESTERLIES TO THE NORTH. THINK
WESTERLY FLOW OVER ARIZONA WILL BE STRONG AND DRY ENOUGH IN THE
EXTENDED TO REMOVE MENTION OF PRECIPITATION. HOWEVER...NEED TO KEEP
A CLOSE EYE ON MOISTURE TO THE SOUTH...IT COULD BE MORE TENACIOUS
THAN MODELS ARE CURRENTLY SHOWING.

MCCOLLUM

.FGZ...NONE.