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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