Severe Thunderstorm Warning 19, NWS Tucson, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
900 PM MST THU JUL 15 2004

SOUTHEAST ARIZONA FORECAST DISCUSSION

.SYNOPSIS...HIGH PRESSURE ALOFT CENTERED OVER COLORADO WILL KEEP A
MOIST EAST TO SOUTHEAST FLOW INTO ARIZONA THIS WEEK. THE RISK OF
THUNDERSTORMS SHOULD DECREASE SOMEWHAT OVER THE WEEKEND AS THE UPPER
HIGH MOVES SOUTH AND CUTS OFF SOME OF THE MOISTURE SUPPLY.
&&

.DISCUSSION...BUSY TIME TODAY...MUCH BETTER THUNDERSTORM COVERAGE
WITH BETTER MIXTURE OF MOISTURE AND SUNSHINE. EASTERLY IMPULSE UNDER
THE HIGH WILL LIKELY HELP KEEP STORMS COMING IN FROM NEW MEXICO
GOING OVERNIGHT IN SOME FORM. COULD EVENTUALLY BE REDUCED TO FIRING
ALONG THE OUTFLOW AT TIMES WITH 25 TO 40KTS COMING IN FROM THE EAST.

WITH HIGH CENTER RECONSOLIDATING FURTHER SOUTH OVER THE
WEEKEND...WELL SEE A SLIGHTLY DRIER FLOW OVER PORTIONS OF THE AREA
AS THE EASTERLIES AND EMBEDDED IMPULSES ARE PUSHED TO LOWER
LATITUDES FOR A FEW DAYS. WITH THE WEAK DRYING TREND AND PROXIMITY
OF THE HIGH...EXPECT TEMPERATURES TO CLIMB TO WELL OVER THE CENTURY
MARK MOST PLACES (UP 5 TO 8 DEGREES OVER RECENT DAYS). DRY IS A
RELATIVE TERM...AS WE WILL LIKELY MAINTAIN ENOUGH MOISTURE FOR A
LOW-GRADE MONSOON FORECAST WITH ISOLATED TO LOW SCATTERED COVERAGE
FOR SHOWERS AND THUNDERSTORMS.
&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1156 AM MST THU JUL 15 2004

AZZ019-029>035-160700-
NORTHERN GREENLEE COUNTY-UPPER GILA RIVER VALLEY-COCHISE COUNTY-
SOUTHEAST PINAL COUNTY-TUCSON METRO/MARANA/GREEN VALLEY-
SANTA CRUZ COUNTY-TOHONO OODHAM NATION-WESTERN PIMA COUNTY-
1156 AM MST THU JUL 15 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST ARIZONA

.DAY ONE...TODAY

SYNOPSIS...THERE IS A HIGHER RISK OF SEVERE DOWNBURST WINDS WITH
LOCALIZED HEAVY RAIN TO THE EAST OF TUCSON TODAY...WITH AN HIGHER
RISK OF MORE WIDESPREAD VERY HEAVY RAINFALL WEST OF TUCSON.

DISCUSSION...A WEAK UPPER LEVEL DISTURBANCE...WHICH ORIGINATED FROM
SOUTHERN OKLAHOMA LAST NIGHT...WILL CONTINUE TO ROTATE EAST THROUGH
SOUTH CENTRAL NEW MEXICO ALONG THE BASE OF THE UPPER RIDGE TODAY...
AND EVENTUALLY WILL PUSH INTO THE FAR SOUTHEAST CORNER OF ARIZONA
LATER THIS AFTERNOON. THIS DISTURBANCE WILL ACT AS A TRIGGERING
MECHANISM FOR THUNDERSTORM INITIATION THIS AFTERNOON. IN ADDITION...
BOTH THE MID AND UPPER LEVEL HIGH CENTERS LOCATED OVER COLORADO THIS
MORNING WILL SHIFT SOUTHEAST TOWARDS THE TEXAS PANHANDLE. THIS WILL
ALLOW THE FLOW ALOFT TO BECOME DIFFLUENT...THUS ALSO AIDING
CONVECTIVE INITIATION. THIS DIFFLUENT AREA WILL PUSH INTO THE FAR
SOUTHEAST CORNER OF ARIZONA BY LATE THIS AFTERNOON...AND THEN WILL
SHIFT NORTHWEST INTO CENTRAL ARIZONA BY LATE THIS EVENING.

THE GOES-10 PRECIPITABLE WATER IMAGERY AND SURFACE OBSERVATIONS
INDICATED THAT LOCATIONS WEST OF TUCSON REMAIN VERY MOIST IN THE LOW
LEVELS...WITH AREAS EAST OF TUCSON BEGINNING TO SEE SOME DRYING
COMING IN FROM THE EAST. GIVEN THIS...THERE IS A HIGHER RISK OF
SEVERE DOWNBURST WINDS WITH LOCALIZED VERY HEAVY RAIN TO THE EAST OF
TUCSON TODAY...WITH AN HIGHER RISK OF MORE WIDESPREAD VERY HEAVY
RAINFALL WEST OF TUCSON. THUNDERSTORM ACTIVITY WILL BEGIN LATER THIS
AFTERNOON IN THE EASTERN MOUNTAINS...PUSH INTO THE VALLEYS BY LATE
AFTERNOON AND THEN PUSH WEST INTO THE LOWER DESERTS BY EARLY THIS
EVENING. STORM MOTION WILL BE TO THE WEST NORTHWEST AT 15 MPH TODAY.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

THUNDERSTORM ACTIVITY ACROSS SOUTHEAST ARIZONA WILL SLOWLY DECREASE
THIS WEEKEND AND EARLY NEXT WEEK AS THE UPPER HIGH CENTER MOVES
FURTHER SOUTH...CUTTING OFF THE MOISTURE SUPPLY FROM THE SOUTH AND
SOUTHEAST. HOWEVER...ENOUGH MOISTURE WILL STILL REMAIN IN PLACE FOR
ISOLATED TO SCATTERED THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.