Drought in Arizona, September 1 to 16, 2013

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
900 PM MST SAT AUG 31 2013

.SYNOPSIS...EXPECT ISOLATED TO SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS DURING THE UPCOMING WEEK. A WARMING TREND WILL ALSO
OCCUR THROUGH TUESDAY FOLLOWED BY ABOVE AVERAGE DAYTIME TEMPERATURES
LATER IN THE WEEK.

&&

.DISCUSSION...MOISTURE SETTLING BACK TOWARD CLIMO WITH 00Z KTWC
PRECIPITABLE WATER DOWN TO ABOUT 1.25 INCHES AND 24 HOUR SURFACE
DEWPT TRENDS DOWN 3-5 DEGREES. ADD IN MODEST MID LEVEL TEMPERATURES
AND WEAK STORM LEVEL FLOW FOR MAINLY MOUNTAIN HUGGING STORMS TODAY.
COMPLEX IN NORTHERN SONORA COULD STILL PUSH CONVECTION EMBEDDED IN
DEBRIS CLOUD OVER THE BORDER THIS EVENING...OTHERWISE NOT MUCH
POTENTIAL OVERNIGHT.

&&

.PREV DISCUSSION...THE COVERAGE OF SHOWERS/TSTMS SUNDAY AFTERNOON
AND EVENING SHOULD BE SIMILAR OR PERHAPS EVEN LESS VERSUS THIS
AFTERNOON AND EVENING. THE BEST CHANCE OF RAINFALL WILL OCCUR ACROSS
THE WHITE MOUNTAINS AND SOUTH OF TUCSON.

MON-TUE...
SOMEWHAT MORE COVERAGE OF SHOWERS/TSTMS SHOULD OCCUR ESPECIALLY TUE
AFTERNOON/EVE AS THE MID-LEVEL ELY FLOW INCREASES...AND AN INVERTED
TROUGH IS PROGGED TO MOVE WWD ACROSS NRN SONORA. HAVE MAINTAINED
SCATTERED AFTERNOON AND EVENING SHOWERS/TSTMS FROM TUCSON EWD/SWD
WITH ISOLATED SHOWERS/TSTMS ACROSS WRN PIMA COUNTY AND SOUTH CENTRAL
PINAL COUNTY.

WED-SAT...
31/12Z GFS/ECMWF WERE SIMILAR WITH DEPICTING A SOMEWHAT DRIER MID-
LEVEL REGIME TO PREVAIL THIS PERIOD. HAVE NOTED THAT THE ECMWF
PRODUCED VIRTUALLY ZERO QPF/S ACROSS SE AZ THUR-SAT. MEANWHILE...
THE GFS LIMITED QPF/S TO MAINLY ACROSS THE WHITE MOUNTAINS THUR-
SAT. AT ANY RATE...THE OFFICIAL FORECAST DEPICTS SCATTERED AFTERNOON
AND EVENING SHOWERS/TSTMS EAST AND SOUTH OF TUCSON WED WITH ISOLATED
SHOWERS/TSTMS ELSEWHERE. HAVE OPTED FOR ONLY ISOLATED AFTERNOON AND
EVENING SHOWERS/TSTMS FOR MUCH OF THE AREA THUR-SAT.

EXPECT ABOUT 2-3 DEGS F OF DAILY WARMING PARTICULARLY AT LOWER
ELEVATIONS SUN-TUE. THEREAFTER...ONLY VERY MINOR DAILY TEMP CHANGES
ARE FORECAST TO OCCUR WED-SAT.

&&

.AVIATION...CLEARING OVERNIGHT WITH ISOLD -SHRA LATE TONIGHT AND
SUNDAY MORNING MAINLY NEAR THE INTERNATIONAL BORDER. ISOLD-SCTD
TSRA/SHRA AGAIN SUNDAY AFTERNOON AND SUNDAY EVENING. THE STRONGER
TSRA WILL PRODUCE MVFR CIGS/VSBYS AND WIND GUSTS TO NEAR 40 KTS.
OTHERWISE...SURFACE WIND GENERALLY LESS THAN 10 KTS THRU SUNDAY
EVENING OR 02/06Z. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.

&&

.FIRE WEATHER...MOIST AIRMASS OVER SOUTHERN ARIZONA WITH A HIGH
PRESSURE CENTERED NEAR CENTRAL NEW MEXICO. THIS HIGH WOBBLES AROUND
TO A LOCATION NEAR THE FOUR CORNERS AREA BY THE MIDDLE OF NEXT WEEK.
LIKEWISE THE AIRMASS DRIES SLIGHTLY DURING THIS TIME AS TEMPERATURES
SLOWLY INCREASE. SUFFICIENT MOISTURE REMAINS DURING THE UPCOMING
WEEK FOR ISOLATED TO SCATTERED SHOWERS AND AFTERNOON THUNDERSTORMS
EACH DAY. STRONG...GUSTY AND ERRATIC WINDS WILL OCCUR WITH THE
STRONGER AFTERNOON THUNDERSTORMS. AWAY FROM THE SHOWERS AND
THUNDERSTORMS NORMAL DIURNAL WIND TRENDS WILL PREVAIL WITH SPEEDS
LESS THAN 15 MPH.

&&

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

&&

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