Dust Storm Warning 7, NWS Tucson, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
900 AM MST FRI SEP 6 2013

.SYNOPSIS...A BIT MORE AREAL COVERAGE IN THUNDERSTORMS AS A WEAK
DISTURBANCE ALOFT MOVES ACROSS THE AREA.  DEEPER TROPICAL MOISTURE
WILL RETURN TO THE AREA FROM THE SOUTH THIS WEEKEND FOR AN INCREASE
IN SHOWERS AND THUNDERSTORMS BY SUNDAY WITH SHOWERS CONTINUING
THROUGH THE EARLY PART OF NEXT WEEK.

&&

.DISCUSSION...PRECIPITABLE WATER VALUES A COUPLE OF TENTHS HIGHER
THIS MORNING COMPARED TO 24 HRS AGO OR LAST EVENING FOR THAT
MATTER.  THE EVIDENCE OF THAT IS THE MID LEVEL CLOUD DECK ACROSS THE
SOUTHERN TWO-THIRDS OF THE FORECAST AREA.  THAT IN COMBINATION WITH
A WEAK UPPER LEVEL DISTURBANCE NEAR THE BOOTHEEL OF NEW MEXICO
SHOULD ALLOW FOR AN INCREASE IN CONVECTION TODAY.  SHOWERS ALREADY
EVIDENT OVER THE SOUTHEAST CORNER OF COCHISE COUNTY WITH A COUPLE OF
T-STORMS RIGHT UNDER THE VORTICITY CENTER JUST EAST OF THE
BOOTHEEL.  THIS FEATURE WILL DRIFT WEST-NORTHWEST ACROSS THE AREA
DURING THE DAY TODAY PROVIDING A FOCUSING MECHANISM.  CONSIDERING
TIMING OF THIS COINCIDING WITH DAYTIME HEATING PUTS THE FOCUS OF
SIGNIFICANT CONVECTION OVER THE WESTERN TWO-THIRDS OF THE FORECAST
AREA THIS AFTERNOON...AND FAR WESTERN AREAS THIS EVENING.  LOWER
LEVEL AIR MASS DRY ENOUGH TO AID DOWNDRAFTS ESPECIALLY WESTERN AREAS
WHERE DCAPE IS THE HIGHEST BUT WITH A BIT MORE MOISTURE THAN
YESTERDAY THERE IS A BETTER SHOT OF MORE SIGNIFICANT RAINS FROM THE
CELLS.  WITH A BIT MORE MOISTURE AND CLOUDS ACROSS THE REGION HIGH
TEMPERATURES ARE EXPECTED TO BE A COUPLE OF DEGREES COOLER MOST
LOCATIONS TODAY AND LIKELY TO REMAIN MILD TONIGHT.  CERNIGLIA

.REMAINDER OF FORECAST PERIOD FROM PREVIOUS DISCUSSION...MAIN THEME
FOR THE REMAINDER OF THE FORECAST CYCLE WILL BE WETTER CONDITIONS AS
TROPICAL MOISTURE FROM TS LORENA STREAMS NORTH THIS WEEKEND WITH
CONTINUED FLOW FROM THE SOUTH THROUGH MUCH OF NEXT WEEK. COULD RUN
INTO A PERIOD WHERE SOME PARTS OF THE AREA WILL NEED TO BE UNDER
FLASH FLOOD WATCH...BUT AS DAYSHIFT POINTED OUT YESTERDAY IT WILL BE
HARD TO PINPOINT WHEN THE BEST CHANCES FOR THIS TO OCCUR. THERE IS
THE POTENTIAL THAT RAINFALL OVER THE NEXT WEEK COULD BE A 2013
MONSOON SAVER FOR SOME SPOTS...WHILE ALSO ADDING TO THE NEAR RECORD
MONSOON RAINFALL THAT SOME AREAS HAVE ALREADY SEEN THIS MONSOON.

&&

.AVIATION...ISOLD-SCT TSRA/SHRA WILL OCCUR THRU THIS EVENING
FOLLOWED BY ISOLD -SHRA LATE TONIGHT INTO EARLY SATURDAY MORNING.
THE STRONGER TSRA WILL PRODUCE MVFR CIGS/VSBYS AND BRIEF WIND GUSTS
TO AROUND 40 KTS. OTHERWISE...CLOUD DECKS THIS AFTERNOON AND THIS
EVENING WILL GENERALLY BE AROUND 7-11K FT AGL THEN MOSTLY ABOVE 12K
FT AGL LATE TONIGHT AND EARLY SATURDAY MORNING. SURFACE WIND WILL BE
MAINLY ELY/SELY 5-15 KTS THRU EARLY SATURDAY MORNING OR 07/12Z.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...EXPECT ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH THIS EVENING FOLLOWED BY ISOLATED SHOWERS LATE
TONIGHT. A STRONG MOISTURE INCREASE FROM THE SOUTH WILL BRING A MUCH
BETTER CHANCE OF SHOWERS AND THUNDERSTORMS BY SUNDAY AND CONTINUING
INTO EARLY NEXT WEEK. IN THE MEANTIME...GUSTY EASTERLY WINDS OF UP
TO 20 MPH WILL OCCUR TODAY.

&&

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

&&

VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON