804
FXUS65 KTWC 131613
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
913 AM MST THU AUG 13 2026
SYNOPSIS
AN UPPER LEVEL WEATHER SYSTEM TO OUR WEST WILL
BRING THE NEEDED DYNAMICS TODAY FOR SCATTERED SHOWERS AND
THUNDERSTORMS. SOME OF THE STORMS WILL PRODUCE BRIEF HEAVY RAIN.
THIS SYSTEM WILL ALSO DRAW IN DRIER AIR FRIDAY INTO THE WEEKEND
RESULTING IN A LOW-GRADE MONSOON PATTERN WITH CHANCE OF STORMS
EACH DAY MAINLY SOUTH AND EAST OF TUCSON. A LITTLE MORE ACTIVE
MONSOON PATTERN SETS IN EARLY NEXT WEEK. TEMPERATURES WILL BE
BELOW NORMAL TODAY, THEN WARM UP AGAIN TO ABOVE NORMAL THIS
WEEKEND INTO NEXT WEEK WITH MODERATE HEATRISK
UPDATE
LINGERING SHOWERS FROM OVERNIGHT ARE NOW FOCUSED IN SOUTHERN
COCHISE COUNTY. THESE SHOWERS WILL CONTINUE TO MOVE EASTWARD FOR
THE NEXT FEW HOURS. DECENT CLEARING IS UNDERWAY FOR AREAS TUCSON
WESTWARD THIS MORNING WITH SOME HIGH CIRRUS MOVING INTO WESTERN
PIMA COUNTY. SUBSTANTIAL MOISTURE REMAINS IN PLACE THIS MORNING
WITH SATELLITE DERIVED PWATS AROUND 1.3" TO 1.7", HIGHER TUCSON
WESTWARD AN SURFACE DEWPOINTS IN THE UPPER 60S. TODAY, THE
WEATHER PREDICTION CENTER (WPC) HAS AREAS TUCSON EASTWARD IN
SLIGHT RISK FOR EXCESSIVE RAINFALL. THE 12Z HREF HIGHLIGHTS THIS
AREA WITH A 10-30% CHANCE FOR GREATER THAN 1 INCH OF RAINFALL,
IN A 3 HOUR PERIOD, WITH POCKETS OF UP TO 2 INCHES POSSIBLE.
WHILE THERE IS SUITABLE INSTABILITY IN PLACE, THE MAIN CONCERN
TODAY IS FLASH FLOODING. RAINFALL OVERNIGHT AND OVER THE PAST
SEVERAL DAYS HAS MADE THE AREA HIGHLY SUSCEPTIBLE FOR FLASH
FLOODING THUS ANY MORE RAIN THAT FALLS WILL HAVE A MUCH HIGHER
CHANCE TO CAUSE IMPACTS. TEMPERATURES TODAY WILL BE 5 TO 7
DEGREES BELOW NORMAL.
DISCUSSION
BEEN A BUSY SOLO MORNING WITH SHOWERS AND ISOLATED
THUNDERSTORMS MOVING ACROSS EASTERN PINAL, EASTERN PIMA, SOUTHERN
GRAHAM AND NORTHWEST COCHISE COUNTY. SOME OF THE HEAVIER
SHOWERS HAVE HAD SOME IMPRESSIVE RAINFALL RATES, UP TO 2"/HR,
WHICH RESULTED A FEW SMALL STREAM ADVISORIES AND A FLASH FLOOD
WARNING BEING ISSUED. SOME WASHES ACROSS THE ABOVE MENTIONED
AREAS HAVE SEEN SOME GOOD RESPONSES TO THE RAINFALL. ALL OF THIS
IS ASSOCIATED WITH AN UPPER LEVEL TROF TO OUR WEST THAT
EXTENDED FROM WRN NV TO SRN CA. THESE SHOWERS/STORMS WILL
CONTINUE TO MOVE TO THE EAST-NORTHEAST THIS MORNING AND
GRADUALLY DECREASE IN AREAL COVERAGE AS THE MORNING PROGRESSES.
SATELLITE IMAGERY THIS MORNING SHOWED CLEARER SKIES ACROSS
SOUTHWEST ARIZONA. SO EXPECT PARTLY CLOUDY SKIES ONCE THE
SHOWERS END AND THEN SEE SCATTERED REDEVELOPMENT OF LOW-TOPPED
SHOWERS/STORMS WITH THE AFTERNOON HEATING AND THE DYNAMICS
ASSOCIATED WITH THE ABOVE MENTIONED TROF. CAN'T RULE OUT A
FRISKY STORM OR TWO PRODUCING VERY SMALL HAIL WITH THE COOL
SUMMER MID-LEVEL 500 MB TEMPS OF -6C.
DRIER DOES FILTERS IN ACROSS THE AREA TOMORROW AND CONTINUING
INTO THIS WEEKEND. STILL ENOUGH MOISTURE AROUND FOR A CHANCE OF
AFTERNOON/EVENING STORMS MAINLY SOUTH AND EAST OF TUCSON. THE
ONCE CAVEAT TO THIS IS THE POTENTIAL FOR AN EASTERLY WAVE, WHICH
IS CURRENTLY ALONG THE MEXICAN COAST OF THE GOA, MOVING ACROSS
NORTHERN MEXICO ON SUNDAY. SOMETHING TO KEEP AN EYE ONE AS THIS
MAY BRING A BETTER CHANCE OF STORMS THAT WHAT IS CURRENTLY IN
THE FORECAST.
TEMPERATURES WILL BE BELOW NORMAL TODAY, THEN WARM UP AGAIN TO
ABOVE NORMAL THIS WEEKEND INTO NEXT WEEK WITH MODERATE TO
LOCALIZED MAJOR HEATRISK AND TRIPLE DIGIT HIGHS RETURNING TO
MOST OF THE AREA.
AVIATION /14Z THURSDAY THROUGH 14Z FRIDAY/
VALID THROUGH 14/12Z.
AREA OF SHOWERS AND ISOLATED THUNDERSTORMS WITH CEILING BASES
7-11K FT AGL FROM KTUS EAST DIMINISHING AND COND IMPROVING BY
13/18Z. AFT 13/19Z, WDLY SCTD -SHRA/-TSRA WITH GUSTY ERRATIC
WINDS OF 30-40 KTS POSSIBLE WITH ANY THUNDERSTORM. OUTSIDE OF
STORMS SFC WINDS WLY/NWLY AT 8-12 KTS WITH OCNL GUSTS TO 20 KTS.
SFC WINDS LIGHT AND TERRAIN DRIVEN BETWEEN 14/06Z AND 14/16Z.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
AN UPPER LEVEL WEATHER SYSTEM TO OUR WEST WILL
BRING THE NEEDED DYNAMICS TODAY FOR SCATTERED SHOWERS AND
THUNDERSTORMS. SOME OF THE STORMS WILL PRODUCE BRIEF HEAVY RAIN.
THIS SYSTEM WILL ALSO DRAW IN DRIER AIR FRIDAY INTO THE WEEKEND
RESULTING IN A LOW-GRADE MONSOON PATTERN WITH CHANCE OF STORMS
EACH DAY MAINLY SOUTH AND EAST OF TUCSON. A LITTLE MORE ACTIVE
MONSOON PATTERN SETS IN EARLY NEXT WEEK. MINIMUM RELATIVE
HUMIDITY WILL BE 20-40 PERCENT TODAY LOWERING TO AROUND 15-30
PERCENT THEREAFTER. TEMPERATURES WILL BE BELOW NORMAL TODAY,
THEN WARM UP AGAIN TO ABOVE NORMAL THIS. OUTSIDE OF
THUNDERSTORMS, WINDS TERRAIN DRIVEN TO AROUND 10 MPH WITH
OCCASIONAL AFTERNOON GUSTS TO 20 MPH.
TWC WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...MALARKEY
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