Special Weather Statement, NWS Tucson, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
915 AM MST FRI AUG 7 2015

.SYNOPSIS...AFTER A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS
TODAY...THE FLOW WILL BECOME LESS FAVORABLE FOR STORMS OVER THE
WEEKEND. THE BEST CHANCES MOVE EAST AND SOUTHEAST OF TUCSON SATURDAY
AND SUNDAY. THEREAFTER...ANOTHER INCREASE IN THUNDERSTORMS IS
EXPECTED LATER MONDAY INTO TUESDAY.

&&

.DISCUSSION...THE 12Z KTWC SOUNDING WAS VERY MOIST AND UNSTABLE. A
RATHER LOW CONVECTIVE TEMPERATURE WITH A FEW WEAK STORMS ALREADY
BUBBLING AROUND SOME DEBRIS FROM LAST NIGHT. WE WON'T NEED AS MUCH
SUN AS WE USUALLY DO...BUT WE WILL NEED SOME. FORTUNATELY THE
CLEARING TRENDS ARE MORE PROMISING THAN YESTERDAY WITHOUT THE STRONG
REMNANT CIRCULATION IN THE DEBRIS WE SAW MOVE THROUGH CENTRAL AND
WESTERN PIMA COUNTY YESTERDAY MORNING.

WITH CURRENT TRENDS WE MAY SEE DELAYED DEVELOPMENT OVER COCHISE
COUNTY WITH BETTER CHANCES FOR MORE TYPICAL DIURNAL STORM TRENDS ON
THE WESTERN EDGE OF THE DEBRIS CLOUD. THAT WOULD FAVOR INITIAL
DEVELOPMENT IN PORTIONS OF SANTA CRUZ AND EASTERN PIMA COUNTY.
CURRENT FORECAST TRENDS HANDLE THAT PRETTY WELL.

PLEASE SEE THE PREVIOUS DISCUSSION BELOW FOR ADDITIONAL DETAILS.

&&

.AVIATION...VALID THRU 08/18Z.
SCT-BKN CLOUDS 9-13 KFT AGL WILL CONTINUE TO THIN THIS MORNING WITH
SKIES GRADUALLY CLEARING. AFTER 07/19Z SCT-BKN CLOUDS DEVELOPING 7-
10 KFT ALONG WITH SCT SHRA/TSRA THRU THE AFTERNOON. LOCAL MVFR CONDS
AND STRONG WIND GUSTS TO NEAR 40 KTS IN AND NEAR TSRA. DECREASING
SHRA/TSRA COVERAGE AFTER 08/03Z. SURFACE WINDS GENERALLY LESS THAN
12 KTS OUTSIDE OF THUNDERSTORMS WITH TYPICAL AFTERNOON
GUSTINESS...ESPECIALLY IN THE VICINITY OF KSAD. AVIATION DISCUSSION
NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...PLENTY OF MOISTURE WILL LINGER TODAY WITH SCATTERED
TO NUMEROUS SHOWERS AND THUNDERSTORMS EXPECTED TO DEVELOP. STORMS
THAT DO DEVELOP WILL BE CAPABLE OF PRODUCING STRONG WINDS NEAR 45
MPH AND LOCALLY HEAVY RAIN. ANOTHER ACTIVE DAY IS EXPECTED
SATURDAY...BUT THIS TIME WITH A FOCUS EAST OF TUCSON. ACTIVITY WILL
THEN RAMP BACK UP ON MONDAY AND TUESDAY BEFORE ANOTHER DOWNSWING
TOWARDS THE MIDDLE OF NEXT WEEK. OUTSIDE OF THUNDERSTORMS...WINDS
WILL GENERALLY BE LIGHT AND DIURNAL WITH THE NORMAL AFTERNOON
WESTERLIES THROUGH MONDAY. THEN WINDS BECOMING PREDOMINATELY
EASTERLY TUESDAY ONWARD.

&&

.PREV DISCUSSION...IR SATELLITE LOOPS THIS MORNING SHOW CLOUD TOPS
WARMING AS A LARGE THUNDERSTORM COMPLEX WEAKENS IN NORTHERN SONORA
MEXICO. AT THE SAME TIME...WE'RE BEGINNING TO CLOUD OVER EAST OF
TUCSON AS THE OLD THUNDERSTORM ANVILS BLOW OFF INTO EASTERN
AZ...HOWEVER EVEN THIS CLOUD COVER APPEARS TO BE THINNING SLOWLY. AT
THE SURFACE...WE CONTINUE TO MOISTEN IN THE LOW-LEVELS WITH
DEWPOINTS THIS HOUR RUNNING GENERALLY IN THE LOWER 60S F...UP ABOUT
4-10 DEGS F FROM 24 HOURS AGO. THE CIRA LAYERED PWAT PRODUCT SHOWS
PW VALUES RANGING FROM NEAR 1 INCH NEAR THE AZ/NM BORDER UP TO ABOUT
1.4-1.6 INCH FROM TUCSON AND POINTS WEST. WE CERTAINLY HAVE THE
JUICE IN PLACE THIS MORNING.

GFS AND NAM FORECAST SOUNDINGS TODAY SHOW DECENT CONVECTIVE
POTENTIAL FOR TUCSON AND EVEN AS FAR WEST AS SELLS...BUT THEY'LL BE
FIGHTING WITH HIGHER LFCS AND A SOMEWHAT DRIER BOUNDARY LAYER THAT
FAR WEST. ASSUMING EARLY-MORNING CLOUD COVER CONTINUES TO ERODE...IT
LOOKS LIKE WE COULD BE SET UP FOR GOOD THUNDERSTORM COVERAGE TODAY
FOR MAINLY CENTRAL AND EASTERN ZONES WITH PERHAPS MORE ISOLATED
COVERAGE INTO PARTS OF THE TOHONO O'ODHAM NATION. THIS SCENARIO IS
DEPICTED NICELY BY THE UNIV. OF AZ WRFS...NCAR ENSEMBLE...AND THE
07/05Z HRRRX (WHICH ADMITTEDLY WAS NOT HANDLING CURRENT TRENDS TOO
WELL). PER COORDINATION WITH PSR...ADDED PATCHY BLOWING DUST WORDING
FOR SOUTH-CENTRAL PINAL COUNTY THIS EVENING WHERE THE LAND
INFORMATION SYSTEM INDICATES WE'RE HOLDING ONTO THE DRIEST RELATIVE
SOIL MOISTURE VALUES IN OUR CWA...IN THE 10S TO NEAR 20 PERCENT AND
WHERE HIRES MODEL SOLUTIONS POINT TO SOME GUSTY OUTFLOW POTENTIAL.

MOISTURE WILL CONTINUE TO GET DRAGGED EAST THIS WEEKEND AS THE MID-
LEVEL HIGH SLIDES TOWARDS THE ARKLATEX. TUCSON MAY VERY WELL BE THE
DIVIDING LINE FOR PRECIPITATION CHANCES ON SATURDAY BEFORE THEY'RE
RELEGATED TO EASTERN AND SOUTHERN ZONES ON SUNDAY.

ON MONDAY AND TUESDAY WE SHOULD SEE SOME RESURGENCE OF ACTIVITY AS
THE HIGH BEGINS TO PINWHEEL BACK WEST TOWARDS NM. BY THE MIDDLE OF
NEXT WEEK HOWEVER...THE HIGH SHOULD GET CLOSE ENOUGH TO BEGIN
SHUTTING EASTERN ZONES DOWN A BIT.

&&

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

&&

MEYER
PREV DISCUSSION...CARLAW

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

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TUCSON AZ
1211 PM MST FRI AUG 7 2015

AZZ506-509-511-072000-
UPPER GILA RIVER AND ARAVAIPA VALLEYS INCLUDING CLIFTON/SAFFORD AZ-
GALIURO AND PINALENO MOUNTAINS INCLUDING MOUNT GRAHAM AZ-
SOUTHEAST PINAL COUNTY INCLUDING KEARNY/MAMMOTH/ORACLE AZ-
1211 PM MST FRI AUG 7 2015

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL PINAL AND WEST
CENTRAL GRAHAM COUNTIES UNTIL 100 PM MST...

AT 1211 PM MST...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 5
MILES NORTHWEST OF KLONDYKE...MOVING NORTH AT 10 MPH.

HALF INCH HAIL AND WINDS IN EXCESS OF 45 MPH WILL BE POSSIBLE WITH
THIS STORM.

LOCATIONS IMPACTED INCLUDE...
KLONDYKE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

&&

LAT...LON 3276 11031 3280 11054 3314 11049 3309 11013
TIME...MOT...LOC 1911Z 195DEG 19KT 3293 11039

MEYER