Area Forecast Discussion
Issued by NWS Tucson, AZ

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS65 KTWC 122152
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
250 PM MST FRI SEP 12 2014

.SYNOPSIS...EXPECT ISOLATED TO SCATTERED THUNDERSTORMS THIS EVENING.
STRONG AND GUSTY EAST WINDS WILL DEVELOP TONIGHT INTO SATURDAY
FOLLOWED BY SEVERAL DEGREES OF COOLING ALONG WITH A REDUCED CHANCE
OF STORMS THIS WEEKEND. THE CHANCE FOR THUNDERSTORMS WILL INCREASE
DURING THE UPCOMING WEEK AS MOISTURE INCREASES ACROSS THE AREA FROM
THE SOUTH.

&&

.DISCUSSION...ISOLATED SHOWERS AND THUNDERSTORMS WERE ONGOING ACROSS
MUCH OF SE AZ AT THIS TIME. OTHERWISE...SATELLITE IMAGERY AND
SURFACE OBSERVATIONS DEPICTED A FEW TO SCATTERED CUMULOFORM CLOUDS
ACROSS MUCH OF THE AREA EXCEPT FOR SUNNY SKIES ACROSS WRN PIMA
COUNTY.

HAVE CONTINUED WITH ISOLATED TO SCATTERED SHOWERS/TSTMS ACROSS MUCH
OF THE AREA THIS EVENING...AND ISOLATED SHOWERS/TSTMS FOR THE TUCSON
METRO AREA WWD INTO THE TOHONO O`ODHAM NATION. THE BULK OF THESE
SHOWERS/TSTMS SHOULD END BY AROUND MIDNIGHT OR SO. HOWEVER...THERE
APPEARS TO BE ENOUGH MOISTURE TO JUSTIFY A SLIGHT CHANCE OF SHOWERS/
TSTMS ACROSS ERN SECTIONS LATE TONIGHT.

THE MAIN EMPHASIS REGARDING THE WEATHER THIS WEEKEND WILL BE THE
WIND. GUSTY EAST WINDS ARE EXPECTED TO PREVAIL TONIGHT INTO SATURDAY
IN RESPONSE TO A VERY TIGHT SURFACE PRESSURE GRADIENT. WIND SPEEDS
VIA THE 12/12Z NAM INDICATE THAT WIND ADVISORY CRITERIA WOULD BE
ACHIEVED AT KTUS CENTERED ON 15Z SAT. THE PRESENT BELIEF IS THAT THE
NAM SPEEDS WILL BE INDICATIVE OF GUST SPEEDS AT KTUS VERSUS
SUSTAINED WIND SPEEDS.

AT ANY RATE...THE WIND SHOULD DECREASE SOMEWHAT SAT AFTERNOON THEN
BECOME LOCALLY BREEZY AGAIN SAT NIGHT AND SUN MORNING...AND THEN
DIMINISH CONSIDERABLY SUN AFTERNOON AS THE SURFACE PRESSURE GRADIENT
LOOSENS. OTHERWISE...THE CHANCES FOR SHOWERS/TSTMS ARE EXPECTED TO
GENERALLY DECREASE ACROSS SE AZ THIS WEEKEND AS THE MID-LEVEL FLOW
BECOMES INCREASINGLY SELY/SLY. THIS FLOW REGIME TENDS TO FAVOR THE
WHITE MOUNTAINS AS WELL AS LOCALES SOUTH-TO-SOUTHWEST OF TUCSON FOR
THE BEST PRECIP CHANCES.

MOISTURE IS THEN PROGGED TO SPREAD NWD ACROSS SONORA AND INTO SE AZ
MON-WED AS TROPICAL SYSTEM ODILE MOVES TO THE WEST OF SRN BAJA
CALIFORNIA...THEN EVENTUALLY WEST OF THE BAJA CALIFORNIA SPUR AS PER
THE LATEST NHC TRACK GUIDANCE. HAVE OPTED TO DEPICT A GRADUAL
INCREASE IN PRECIP CHANCES DURING THE EARLY AND MIDDLE PORTION OF
NEXT WEEK. THEREAFTER...HAVE NOTED THAT THE 12/12Z GFS/ECWMF WERE
SIMILAR WITH DEPICTING POTENTIALLY ENHANCED RAINFALL FOR AT LEAST
PORTIONS OF SE AZ WED NIGHT INTO THUR. THE UPSHOT...STILL TOO SOON
TO DETERMINE AN EXACT PERIOD FOR WHAT MAY BECOME THE HEAVIEST
RAINFALL DUE TO THE INFLUENCE OF TROPICAL SYSTEM ODILE.

HIGH TEMPS SAT WILL AVERAGE ABOUT 5 DEGS F COOLER VERSUS FRI...MORE
COOLING ACROSS ERN SECTIONS AND LESSER COOLING WEST OF TUCSON.
THEREAFTER...EXPECT ONLY VERY MINOR DAILY TEMP CHANGES SUN-FRI.

&&

.AVIATION...VALID THRU 14/00Z.
SCT CONVECTION DEVELOPING RESULTING IN SCT CLOUDS 7-11K FT AGL AND
SCT TO LOCALLY BKN CLOUDS 14-19K FT AGL WITH SCT SHRA/TSRA THRU
13/04Z.  AFT 13/04Z EXPECT SCT TO BKN 6-9K FT WITH SCT TO BKN LAYERS
ABV 12K FT.  EAST SURFACE WIND 6-12 KTS INCREASING FROM EAST TO WEST
TO 9-15 KTS WITH GUSTS TO 30 KTS AFT 13/00Z.  GUSTY EAST WINDS WILL
PEAK SATURDAY MORNING WITH LOCATIONS PRONE TO EAST WINDS PEAKING
18-22 KTS WITH GUSTS TO 35 KTS.  WIND EASTING AFTER 13/17Z.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...SCATTERED SHOWERS AND THUNDERSTORMS MAINLY FROM
TUCSON SOUTH AND EAST WILL CONTINUE INTO THE EVENING THEN DIE OFF
OVERNIGHT.  LOCALLY STRONG WINDS ARE POSSIBLE VICINITY OF STRONGER
STORMS.  GENERALLY LIGHT EAST TO SOUTHEAST WINDS WILL INCREASE THIS
EVENING TO BETWEEN 10 AND 20 MPH...WITH GUSTS TO AROUND 30 MPH AND
CONTINUE THROUGH THE FIRST HALF OF SATURDAY.  AREAS PRONE TO EAST
WINDS WILL PEAK OUT AROUND 20-25 MPH WITH GUSTS 35+ MPH EARLY
SATURDAY MORNING.  LITTLE IF ANY CONVECTION EXPECTED THIS WEEKEND
BEYOND TONIGHT.  THEN TROPICAL MOISTURE IS EXPECTED TO INCREASE NEXT
WEEK...WITH TROPICAL STORM ODILE INFLUENCE REACHING THE FORECAST
AREA.  EXPECT AN INCREASE IN SHOWER AND THUNDERSTORM ACTIVITY AND
AREAL COVERAGE AROUND THE MIDDLE OF THE UPCOMING WEEK.

&&

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

&&

$$

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

DISCUSSION...FRANCIS
AVIATION/FIRE WEATHER...CERNIGLIA




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.