558
FXUS65 KTWC 032017
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
117 PM MST MON AUG 3 2026
SYNOPSIS
CHANCES FOR THUNDERSTORMS WILL DEVELOP EACH AFTERNOON AND
EVENING THIS WEEK WITH DAY TO DAY VARIABILITY. THUNDERSTORMS MAY
PRODUCE SEVERE OUTFLOW WINDS WITH AREAS OF BLOWING DUST, AS WELL
AS LOCALLY HEAVY RAINFALL WITH A FLASH FLOODING RISK. HIGH
TEMPERATURES WILL REMAIN A FEW DEGREES ABOVE NORMAL THROUGH THE
WEEK.
DISCUSSION
AN UPPER LEVEL HIGH CURRENTLY CENTERED OVER CENTRAL ARIZONA WILL
GRADUALLY LIFT NORTH INTO THE FOUR CORNERS THROUGH THE WEEK.
THE HIGH'S CURRENT POSITION AND ORIENTATION HAS ALLOWED FOR
ACTIVE EASTERLY FLOW TO SET UP OVER SOUTHEASTERN ARIZONA, WHILE
SURFACE DEW POINTS HAVE INCREASED TO THE UPPER 50S TO LOWER 60S
ACROSS THE AREA. UNDER MODESTLY DIVERGENT FLOW ALOFT,
THUNDERSTORMS ARE EXPECTED TO INITIATE OVER THE SKY ISLANDS AND
WHITE MOUNTAINS EARLY TO MID AFTERNOON TODAY, WITH THE EASTERLY
FLOW MOVING AND EXPANDING THEIR COVERAGE WESTWARD THROUGH THE
EVENING. 1000-2000 J/KG OF MLCAPE AND 1.2-1.6 INCHES OF
PRECIPITABLE WATER WILL PROVIDE AMPLE INSTABILITY, COMBINING
WITH 15-25 KNOTS OF EFFECTIVE SHEAR FOR A SEVERE, ORGANIZED
THUNDERSTORM THREAT. WHILE MOST OF SOUTHEASTERN ARIZONA HAS AT
LEAST A 30-50 PERCENT CHANCE OF THUNDERSTORMS TODAY, COVERAGE
SHOULD BE GREATEST THROUGH SOUTHERN COCHISE, SANTA CRUZ, AND
INTO SOUTH CENTRAL PIMA COUNTIES. IT'S IN THIS AREA, ESPECIALLY
SANTA CRUZ, WHERE POTENTIAL FOR MULTIPLE STORM CELLS AND
SUBSEQUENT FLASH FLOODING IS GREATER. A FLOOD WATCH REMAINS IN
EFFECT THIS AFTERNOON AND EVENING.
ELSEWHERE TODAY A SCATTERED SEVERE WIND THREAT REMAINS,
ESPECIALLY WHERE THE 12Z HREF HIGHLIGHTS THE STRONGER POTENTIAL
FOR ORGANIZED SEVERE OUTFLOWS TRANSITIONING SOUTH OFF THE WHITE
MOUNTAINS THIS AFTERNOON AND THIS EVENING FURTHER WEST IF
THUNDERSTORM OUTFLOWS ORGANIZE WEST OF TUCSON. THESE WINDS WILL
LIKELY PRODUCE A BLOWING DUST THREAT, ESPECIALLY IN DUST PRONE
AREAS OF I-10 EAST OF WILLCOX AND WEST OF TUCSON INTO PINAL AND
THROUGH CENTRAL TO WESTERN PIMA. A BLOWING DUST ADVISORY REMAINS
IN PLACE FOR THIS POTENTIAL, WITH THE POSSIBILITY THAT WARNINGS
WILL BE NEEDED WHERE ORGANIZED OUTFLOWS KICK UP AREAS OF VERY
DENSE BLOWING DUST. FINALLY, AN ISOLATED SEVERE HAIL THREAT
CAN'T BE RULED OUT WITH ANY SUSTAINED THUNDERSTORM TODAY.
ON TUESDAY THE UPPER HIGH NUDGES NORTH SLIGHTLY WHILE KEEPING
EASTERLY FLOW IN PLACE OVER THE REGION. AGAIN SCATTERED
THUNDERSTORMS ARE LIKELY, HOWEVER LOCATION WILL DEPEND ON
TODAY'S ACTION. 12Z GUIDANCE POINTS TO A LATER START WITH AN
EMPHASIS ON EASTERN AREAS, MAINLY GRAHAM, GREENLEE, COCHISE,
INTO SANTA CRUZ COUNTIES. FORECAST SOUNDINGS FURTHER WEST (SUCH
AS AT TUCSON) SHOW A MODEST WARMING INVERSION WHICH WOULD LINE
UP WITH THE START IN THE EAST. A LATE EVENING PUSH INTO
PIMA/PINAL COUNTIES HOWEVER CAN'T BE RULED OUT, DEPENDING ON THE
LONGEVITY AND ORGANIZATION OF OUTFLOWS. THE CAPE/SHEAR
PARAMETER SPACE WILL REMAIN IMPRESSIVE FOR SEVERE WINDS AND
BLOWING DUST, ALONG WITH AN ISOLATED FLASH FLOODING RISK.
ADDITIONAL BLOWING DUST HEADLINES FOR TOMORROW IN EASTERN
LOCATIONS MAY BE NEEDED IF THIS TREND CONTINUES.
FAVORABLE FLOW FOR MONSOON ACTIVITY CONTINUES THROUGH THE WEEK
WITH THE UPPER HIGH DRIFTING NORTH TOWARDS THE FOUR CORNERS
WITH DAY TO DAY VARIABILITY. FORECAST HIGH TEMPERATURES WILL
FALL TO 2-4 DEGREES ABOVE NORMAL, WITH SOME VARIABILITY DUE TO
THUNDERSTORM ACTIVITY AND CLOUD COVER.
AVIATION
VALID THROUGH 05/00Z.
ISOLATED TO SCATTERED THUNDERSTORMS EXPECTED TO DEVELOP THIS
AFTERNOON MAINLY BETWEEN 03/21Z TO 04/03Z WITH LINGERING
ISOLATED ACTIVITY THROUGH 04/06Z. COVERAGE AROUND KTUS MORE
LIKELY 03/23Z-04/03Z AND KOLS 03/22Z-04/04Z. GUSTY ERRATIC WINDS
OF 35-45 KTS POSSIBLE WITH ANY THUNDERSTORM WITH POTENTIALLY
BLOWING DUST. OTHERWISE SFC WINDS WLY/NWLY AT 8-12 KTS WITH
OCCASIONAL AFTERNOON GUSTS TO 20 KTS. SFC WINDS LIGHT AND
TERRAIN DRIVEN AFTER 03/04Z. SCATTERED THUNDERSTORM CHANCES
RETURN TUESDAY AFTERNOON AND EVENING. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
AN ACTIVE MONSOON PERIOD LOOKS FAVORABLE THIS WEEK WITH DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS EACH AFTERNOON AND
EVENING, WITH DAY TO DAY VARIABILITY. MINIMUM RELATIVE HUMIDITY
VALUES WILL LIKELY REMAIN ABOVE 25-40 PERCENT THROUGH THE WEEK
WITH TEMPERATURES 2-4 DEGREES ABOVE NORMAL. OUTSIDE OF
THUNDERSTORMS, WINDS TERRAIN DRIVEN TO AROUND 10 MPH WITH
OCCASIONAL AFTERNOON GUSTS TO 25 MPH.
TWC WATCHES/WARNINGS/ADVISORIES
EXTREME HEAT WARNING UNTIL 8 PM MST THIS EVENING FOR
AZZ501>509.
FLOOD WATCH FROM 2 PM THIS AFTERNOON TO 10 PM MST THIS EVENING
FOR AZZ503-504-507-513-515.
BLOWING DUST ADVISORY FROM 2 PM THIS AFTERNOON TO 8 PM MST
THIS EVENING FOR AZZ503-504-507>509.
BLOWING DUST ADVISORY FROM 4 PM THIS AFTERNOON TO 10 PM MST
THIS EVENING FOR AZZ501-502-505-506.
DISCUSSION...EDWARDS
AVIATION...EDWARDS
FIRE WEATHER...EDWARDS
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