Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 051006
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
306 AM MST WED AUG 5 2015

.SYNOPSIS...HOT CONDITIONS WILL CONTINUE ACROSS SOUTHEAST ARIZONA
TODAY...WITH ANY THUNDERSTORMS CONFINED TO THE WHITE MOUNTAINS AND
INTERNATIONAL BORDER. AS HIGH PRESSURE SHIFTS BACK EAST OF THE
AREA...INCREASING MOISTURE WILL BRING AN INCREASING THUNDERSTORM
TREND LATER IN THE WEEK INTO EARLY NEXT WEEK. AS THIS HAPPENS
TEMPERATURES WILL FALL BACK CLOSER TO SEASONAL AVERAGES.

&&

.DISCUSSION...GOING BACK THROUGH LIGHTNING DATA FROM
YESTERDAY...COULD NOT FIND A SINGLE CG STRIKE IN THE CWA WITH JUST A
FEW SHOWERS POPPING NEAR THE HIGH TERRAIN. IT WAS A DIFFERENT STORY
IN SONORA WHERE A DECENT COMPLEX DEVELOPED DURING THE AFTERNOON.
THIS COMPLEX HAS LONG SINCE DECAYED BUT ITS REMNANTS CONTINUE TO
THROW CLOUD COVER OUR WAY MAINLY OVER SOUTHERN AND EASTERN PORTIONS
OF THE CWA. ANTICIPATE THIS DEBRIS CLOUDINESS TO CONTINUE ERODING
THROUGH THE MORNING GIVING WAY TO MOSTLY SUNNY TO PARTLY CLOUDY
CONDITIONS AND ANOTHER VERY HOT DAY WITH HIGHS RUNNING SOME 6-10
DEGREES ABOVE CLIMATOLOGY AS THE MID-LEVEL HIGH PIVOTS ALMOST
DIRECTLY OVERHEAD. THUNDERSTORM CHANCES WILL AGAIN BE CONFINED TO
THE WHITE MOUNTAINS AND NEAR THE INTERNATIONAL BORDER...RIGHT ALONG
THE MOISTURE GRADIENT WHICH IS DEPICTED NICELY BY RECENT CIRA PWAT
IMAGERY.

THINGS WILL BEGIN TO CHANGE IN A BIG WAY THURSDAY AND FRIDAY AS THE
HIGH MIGRATES INTO NM...OPENING US UP TO A MORE FAVORABLE SLY/SELY
FLOW AND TURNING THE MOISTURE PUMP BACK ON. THIS WILL BE A GRADUAL
PROCESS...SO THURSDAY WILL SEE THE BEST CHANCES SOUTH AND WEST OF
TUCSON...PUSHING INTO CENTRAL AND EASTERN ZONES ON FRIDAY. WE`LL
LIKELY HAVE TO CONTEND WITH SOMEWHAT MORE OF A SLY/SSWLY CLOUD
BEARING FLOW ON FRIDAY WHICH CAN PUT A DAMPER ON ACTIVITY MAKING IT
INTO THE METRO AHEAD OF NORTHWARD-EXPANDING ANVILS...BUT PLENTY OF
TIME TO NAIL THESE LITTLE DETAILS DOWN.

AS THE HIGH CENTER CONTINUES TO PINWHEEL INTO EASTERN TX OVER THE
WEEKEND...PRECIPITATION CHANCES WILL GET NUDGED EWD A BIT TOWARDS
THE AZ/NM BORDER. BOTH THE 05/00Z ECMWF/GFS SHOW A BIT MORE MOISTURE
SLOSHING A TOUCH FARTHER TO THE WEST ON SUNDAY ALONG WITH AN
EMBEDDED MID-LEVEL IMPULSE. NUDGED POPS UP A HAIR OVER CENTRAL AND
WESTERN ZONES TO ACCOUNT FOR THIS.

MODEL DIFFERENCES IN THE POSITION OF THE ALL IMPORTANT SUBTROPICAL
HIGH INCREASE SUBSTANTIALLY ON MONDAY AND BEYOND...THE ECMWF THE
FARTHEST EAST OF THE 05/00Z GFS/GEFS/ECMWF/CMC COMBINATION.
REGARDLESS OF THE MODEL OF CHOICE...THE HIGH SHOULD REMAIN IN A
FAVORABLE ENOUGH POSITION TO WARRANT CONTINUED SLIGHT CHANCE TO
CHANCE CATEGORY POPS THROUGH THE END OF THE FORECAST PERIOD.

&&

.AVIATION...VALID THRU 06/12Z.
SCT-BKN CLOUDS MAINLY ABOVE 20K FT AGL THRU 05/16Z. BETWEEN 05/16Z
AND 05/22Z...FEW-SCT CLOUDS AT 8-12K FT AGL. AFT 05/22Z...SCT CLOUDS
AT 7-11K FT AGL AND SCT-BKN CLOUDS ABOVE 15K FT AGL. SLIGHT CHANCE
OF -SHRA/-TSRA ALONG THE INTERNATIONAL BORDER FROM KOLS TO KDUG AFT
05/21Z. SFC WINDS GENERALLY LESS THAN 12 KTS WITH A FEW HIGHER GUSTS
DURING THE AFTERNOON/EARLY EVENING HOURS...ESPECIALLY IN THE GILA
RIVER VALLEY IN THE VICINITY OF KSAD. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...THERE WILL BE A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS THIS AFTERNOON AND EVENING...MAINLY ALONG THE
INTERNATIONAL BORDER AND IN THE WHITE MOUNTAINS. INCREASING
PRECIPITATION CHANCES ARE THEN EXPECTED LATE THIS WEEK...INTO THE
UPCOMING WEEKEND AS HIGH PRESSURE ALOFT SHIFTS INTO THE SOUTHERN
PLAINS. OUTSIDE OF THUNDERSTORM WIND GUSTS...20-FT WINDS WILL MAINLY
BE TERRAIN DRIVEN AND LESS THAN 15 MPH. HOWEVER...THERE WILL BE SOME
AFTERNOON AND EARLY EVENING BREEZINESS...ESPECIALLY IN THE GILA
RIVER VALLEY NEAR SAFFORD.

&&

.CLIMATE...STRONG HIGH PRESSURE WILL CONTINUE OVER THE AREA
TODAY...BRINGING HOT EARLY AUGUST TEMPERATURES TO THE AREA...WITH A
FEW SPOTS APPROACHING OR TYING RECORD HIGHS. NOT ALL LOCATIONS IN SE
AZ WILL GET INTO THE NEAR RECORD HEAT. BELOW ARE THE SITES THAT WILL
BE AT OR WITHIN THREE DEGREES TODAY.

DATE                     AUG 05
                       FCST RCD/YEAR
TUCSON INTL AIRPORT    107  108/2009
FORT THOMAS            106  109/2009
SAFFORD AG STATION     105  108/1995

&&

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

&&

$$

DISCUSSION...CARLAW
AVIATION/FIRE WEATHER...ZELL

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



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