097  
FXUS65 KTWC 160427  
AFDTWC  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TUCSON AZ  
926 PM MST WED AUG 15 2018  
   
SYNOPSIS
 
A MOIST ATMOSPHERE WILL RESULT IN SCATTERED TO NUMEROUS  
SHOWERS WITH EMBEDDED THUNDERSTORMS THROUGH THURSDAY ALONG WITH  
COOLER TEMPERATURES. A FAIRLY TYPICAL MONSOON PATTERN IS EXPECTED  
THIS WEEKEND INTO EARLY NEXT WEEK WITH TEMPERATURES NEAR TO SLIGHTLY  
ABOVE NORMAL.  
 

 
   
DISCUSSION
 
THE SHOWERS AND THUNDERSTORMS THAT DEVELOPED THIS  
AFTERNOON AND EVENING, MAINLY NEAR THE INTERNATIONAL BORDER AND IN  
GRAHAM COUNTY, CONTINUED TO DISSIPATE AT THIS HOUR. UPDATED THE  
FORECAST TO TRIM BACK RAIN CHANCES FOR THE REST OF TONIGHT.  
OTHERWISE, STILL EXPECTING CONSIDERABLE CLOUDINESS OVERNIGHT FROM  
THE THUNDERSTORM ACTIVITY EARLIER. THAT SAID, THE REST OF THE  
FORECAST LOOKED IN GOOD SHAPE. PLEASE REFER TO THE ADDITIONAL  
SECTIONS FOR MORE DETAILS.  
 

 
   
AVIATION
 
VALID THROUGH 17/06Z.  
ISOLATED THUNDERSTORMS AND SHOWERS CONTINUED TO DISSIPATE AS OF  
16/04Z, WITH MAINLY SCT-BKN CLOUDS AOA 20K FT AGL FROM LEFTOVER  
DEBRIS CLOUDS EXPECTED TONIGHT. ISOLATED TO SCATTERED -SHRA/-TSRA  
AGAIN TOMORROW AFTERNOON AND EVENING FROM TUCSON EASTWARD. BRIEF  
MVFR CONDITIONS POSSIBLE WITH THE -TSRA, OTHERWISE SCT-BKN CLOUD  
BASES GENERALLY 8-12K FT AGL TOMORROW. OUTSIDE OF THUNDERSTORM  
GUSTS, EXPECT SFC WINDS MAINLY LESS THAN 12 KTS. AVIATION DISCUSSION  
NOT UPDATED FOR TAF AMENDMENTS.  
 

 
   
FIRE WEATHER
 
THE PATTERN IS FAVORABLE FOR SCATTERED SHOWERS AND  
THUNDERSTORMS INTO THIS WEEKEND, BUT THERE ARE HINTS OF DRIER  
CONDITIONS BY SUNDAY. NEAR OR SLIGHTLY BELOW NORMAL TEMPERATURES  
WILL CONTINUE THROUGH THE FORECAST PERIOD. 20-FT WINDS WILL BE  
TERRAIN DRIVEN AT LESS THAN 15 MPH, EXCEPT FOR IN AND AROUND  
THUNDERSTORMS WHERE STRONG OUTFLOWS MAY OCCUR.  
 

 
   
PREV DISCUSSION
 
A SIMILAR SETUP IS ON THE TABLE FOR THURSDAY AS  
TODAY WITH DEEP MOISTURE REMAINING ACROSS SOUTHEAST ARIZONA BUT WITH  
VERY WEAK SOUTHERLY FLOW AS THE MID LEVEL HIGH IS JUST EAST OF THE  
AREA. MUCH WILL DEPEND ON HOW MUCH SOLAR INSOLATION THERE IS ON  
THURSDAY BUT THE POTENTIAL WILL ONCE AGAIN EXIST FOR SCATTERED TO  
NUMEROUS THUNDERSTORMS WITH LOCALLY HEAVY RAIN. THE STORMS MAY TEND  
TO FAVOR THE HIGHER TERRAIN GIVEN THE SLOW STEERING FLOW.  
 
THEREAFTER, DEEP MOISTURE WILL REMAIN ON FRIDAY AS THE FLOW BECOMES  
A BIT MORE NORTHEASTERLY. THE MID/UPPER LEVEL HIGH WILL  
RECONSOLIDATE TO OUR NORTHWEST THIS WEEKEND WITH A NORTHEASTERLY  
FLOW PERSISTING SATURDAY. THERE IS SOME INDICATION THAT MOISTURE  
WILL BE LESSENING AS EARLY AS SATURDAY BUT IN PARTICULAR ON SUNDAY.  
WHILE THIS WON'T SHUT THE MONSOON DOWN, IT WILL KEEP THE BEST  
CHANCES OF PRECIPITATION FROM TUCSON SOUTH AND EASTWARD. BY EARLY  
NEXT WEEK, THE MID/UPPER LEVEL HIGH WILL SETUP ACROSS NORTHERN NEW  
MEXICO INTO ARIZONA WITH A MORE EASTERLY STEERING FLOW. PERHAPS SOME  
INCREASED MOISTURE AROUND MONDAY AND TUESDAY BUT THEN A POSSIBLE  
DOWNWARD TREND IN ACTIVITY AS THE HIGH SHIFTS MORE OVERHEAD. STILL  
LOTS OF UNCERTAINTY THAT FAR OUT WITH THE BOTTOMLINE BEING SOME  
THUNDERSTORM CHANCES EVERYDAY IN AT LEAST PORTIONS OF SOUTHEAST  
ARIZONA THROUGH THE FORECAST PERIOD.  
 
TEMPERATURES WILL BE BELOW NORMAL THROUGH THURSDAY BEFORE WARMING UP  
AND BEING NEAR TO EVEN SLIGHTLY ABOVE NORMAL LEVELS FRIDAY INTO  
EARLY NEXT WEEK.  
 

 
   
TWC WATCHES/WARNINGS/ADVISORIES
 
NONE.  

 
 

 
 
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