027  
FXUS65 KTWC 192100  
AFDTWC  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TUCSON AZ  
200 PM MST FRI AUG 19 2022  
   
SYNOPSIS
 
SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE INTO  
NEXT WEEK WITH AN UPTICK IN ACTIVITY TODAY THROUGH THE WEEKEND.  
THE MAIN THREATS WILL BE STRONG GUSTY WINDS AND HEAVY RAINFALL  
ESPECIALLY TODAY THROUGH SATURDAY, WITH RAINFALL AMOUNTS PEAKING  
LATER TODAY INTO SATURDAY. OTHERWISE, TEMPERATURES WILL BE 5-10  
DEGREES BELOW NORMAL INTO EARLY NEXT WEEK.  
 

 
   
DISCUSSION
 
SCATTERED SHOWERS AND THUNDERSTORMS, MAINLY FOCUSED  
ACROSS PINAL, CENTRAL AND EASTERN PIMA COUNTIES SO FAR TODAY, WILL  
CONTINUE TO IMPACT MUCH OF SE AZ THROUGH SATURDAY. SEVERAL FLASH  
FLOOD/FLOOD RELATED ADVISORIES AND WARNINGS HAVE ALREADY BEEN ISSUED  
WITH MORE EXPECTED AS A FLOOD WATCH REMAINS IN EFFECT UNTIL SATURDAY  
EVENING. DEEP MOISTURE ASSOCIATED WITH A LOW PRESSURE SYSTEM THAT  
HAD TROPICAL ORIGIN CAN BE ATTRIBUTED TO THIS EXTENDED PERIOD OF  
RAINFALL AND FLASH FLOOD/FLOOD THREAT. THIS WEATHER SCENARIO CAN BE  
CONSIDERED RATHER RARE AS THIS LOW PRESSURE SYSTEM APPEARED TO  
MAINTAIN SOME FORM OF A LOW LEVEL CIRCULATION AS IT TRACKED WESTWARD  
OVER THE LANDMASS OF NORTHERN MEXICO THIS WEEK. THE CIRCULATION WILL  
REMAIN OVER THE NORTHERN GULF OF CALIFORNIA THROUGH TONIGHT WHERE  
SEA SURFACE TEMPERATURES HAVE BEEN RUNNING AROUND 85 TO NEAR 90  
DEGREES. IT WILL BE INTERESTING TO SEE HOW THIS VERY WARM WATER WILL  
INFLUENCE THE STRENGTH OF THE SYSTEM THROUGH EARLY SATURDAY. AT ANY  
RATE, NO BIG CHANGES TO THE CURRENT FORECAST IN TERMS OF THE FLOOD  
THREAT THROUGH SATURDAY EVENING. THERE WILL LIKELY BE SOME LINGERING  
SHOWERS AND THUNDERSTORMS THROUGH THE EARLY MORNING HOURS ON SUNDAY.  
THAT SAID, THE FLOOD WATCH MIGHT BE EXTENDED IN TIME TO HIGHLIGHT  
THE CONTINUED THREAT DURING THE SATURDAY OVERNIGHT/EARLY SUNDAY  
MORNING HOURS. FOR NOW, WILL WAIT AND SEE HOW THINGS EVOLVE TONIGHT  
AND SATURDAY BEFORE EXTENDING THE WATCH. OTHERWISE, MODELS  
EVENTUALLY EJECT THIS LOW NE ACROSS FAR SE AZ ON SUNDAY AS IT GETS  
PICKED UP BY ANOTHER LOW TRACKING THROUGH THE GREAT BASIN. IN THE  
WAKE OF THIS LOW, THERE WILL BE A NOTICEABLE DECREASE IN RAIN  
CHANCES BY SUNDAY EVENING INTO MONDAY. HOWEVER, THIS DECREASE IN  
SHOWER AND THUNDERSTORM ACTIVITY MIGHT BE BRIEF AS ENSEMBLES  
SUGGESTED ANOTHER UPTICK AS EARLY AS TUESDAY BUT MORE SO WEDNESDAY.  
DAYTIME TEMPERATURES WILL WARM BACK TO NEAR SEASONABLE READINGS  
AFTER THIS WEEKEND.  
 

 
   
AVIATION
 
VALID THROUGH 21/00Z.  
PERIODS OF RAIN SHOWERS AND A FEW THUNDERSTORMS WILL IMPACT THE  
TERMINALS THROUGH THE FORECAST PERIOD. SOME OF THE HEAVIER SHOWERS  
AND THUNDERSTORMS WILL REDUCED VISIBILITIES IN DOWNPOURS WITH CIGS  
BELOW 5KT AGL AND/OR WIND GUSTS OF 40+ KTS. OTHERWISE, WINDS  
FOLLOWING DIURNAL TRENDS AT SPEEDS OF 10KTS OR LESS CAN BE EXPECTED.  
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.  
 

 
   
FIRE WEATHER
 
MONSOONAL THUNDERSTORM ACTIVITY WILL REMAIN ELEVATED  
THROUGH THE WEEKEND WITH ROUNDS OF SHOWERS AND THUNDERSTORMS  
EXPECTED EACH DAY. PRIMARY THREATS INCLUDE STRONG WINDS, LIGHTNING,  
AND FLASH FLOODING. OUTSIDE OF THUNDERSTORM ACTIVITY, WIND TRENDS  
WILL REMAIN LIGHT AND FOLLOW TYPICAL DIURNAL TRENDS.  
 

 
   
TWC WATCHES/WARNINGS/ADVISORIES
 
 
FLOOD WATCH THROUGH SATURDAY EVENING FOR AZZ501>515.  
 

 
 

 
 
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