809
FXUS65 KTWC 301726
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
1026 AM MST MON JUN 30 2025
SYNOPSIS
VERY HOT TODAY WITH THE HOTTEST TEMPERATURES OF THIS
STRETCH. AN EXTREME HEAT WARNING IS IN EFFECT FOR PORTIONS OF
SOUTHEAST ARIZONA. MONSOON MOISTURE INCREASES THIS WEEK WITH THE
MAIN THREATS TODAY AND TUESDAY BEING GUSTY WINDS AND BLOWING DUST,
THEN TRANSITIONING TO A LOCALLY HEAVY RAIN AND ISOLATED FLASH
FLOODING THREAT WITH CONTINUED GUSTY WIND POTENTIAL WEDNESDAY AND
THURSDAY. WHILE SHOWER AND THUNDERSTORM CHANCES CONTINUE
INDEPENDENCE DAY AND THE WEEKEND, COVERAGE IS EXPECTED TO DECREASE.
TEMPERATURES WILL DROP TO NEAR NORMAL LEVELS WEDNESDAY, THEN BELOW
NORMAL TO END THE WEEK.
KEY MESSAGES
-TEMPERATURES PEAK TODAY WITH HIGHS OF 108 TO 114 DEGREES IN THE
DESERTS INCLUDING TUCSON AND UPPER GILA RIVER VALLEY. AN EXTREME
HEAT WARNING IS IN EFFECT FROM 10 AM TO 8 PM FOR THESE LOCALES.
-TEMPERATURES WILL DROP TO NEAR NORMAL LEVELS WEDNESDAY, THEN
BELOW NORMAL TO END THE WEEK
-ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS MAINLY EAST OF
TUCSON TODAY, THEN FROM SELLS EASTWARD TUESDAY. MAIN THREATS TODAY
AND TUESDAY WILL BE GUSTY WINDS, BLOWING DUST AND DRY LIGHTNING
POTENTIAL AS THESE THUNDERSTORMS WON'T PRODUCE MUCH IN THE WAY OF
RAINFALL.
-WEDNESDAY AND THURSDAY, AS MORE ABUNDANT MOISTURE MOVES IN, STORMS
WILL HAVE WIND AND LOCALLY HEAVY RAIN THREATS ALONG WITH ISOLATED
FLASH FLOODING POTENTIAL. STORMS WILL BE FOCUSED ON LOCALES
FROM SELLS EASTWARD.
-SHOWER AND THUNDERSTORM CHANCES CONTINUE INDEPENDENCE DAY AND THIS
WEEKEND BUT LESS COVERAGE COMPARED TO WEDNESDAY AND THURSDAY AS A
LOWER GRADE MONSOON PATTERN DEVELOPS.
DISCUSSION
SUNNY SKIES ACROSS ALL OF SOUTHEAST ARIZONA THIS
MORNING. WE ARE STILL EXPECTING THOSE EXTREME TEMPERATURES THIS
AFTERNOON, ESPECIALLY GIVEN THAT TEMPERATURES AT 9 AM MST ARE
RUNNING 2-4 DEGREES WARMER THAN 24 HOURS AGO AT THIS TIME. WE HAVE
AN EXTREME HEAT WARNING IN EFFECT FOR PORTIONS OF PIMA, SOUTHEAST
PINAL AND THE LOWER ELEVATIONS OF GRAHAM COUNTY UNTIL 8 PM MST
THIS EVENING.
TODAY IS GOING TO BE AN INTERESTING DAY ACROSS SOUTHEAST ARIZONA
AS IT IS REALLY THE FIRST REAL TASTE OF THE MONSOON SEASON. THE
BIG PICTURE IS DEFINED BY THE 500 MB HIGH CENTERED OVER THE NE
HALF OF ARIZONA TODAY WITH AN AMPLIFYING RIDGE OF HIGH PRESSURE AT
300 MB ACROSS THE WESTERN HALF OF THE STATE. THE LATEST GOES TPW
VALUES OF 0.75 INCHES ARE OBSERVED NEAR THE TUCSON METRO AREA WITH
DEEPER MOISTURE VALUES 0.90-1.00 INCHES EAST OF THE SOUTHERN
AZ/NM BORDER. THE NORTHERN POSITION OF THE UPPER HIGH IS ALLOWING
A TIGHTER SURFACE GRADIENT TO DEVELOP ACROSS SW NM THIS MORNING,
WHICH WILL BACK INTO THE SE CORNER OF AZ LATER THIS AFTERNOON INTO
THE EVENING. THIS WILL RESULT IN BREEZY TO LOCALLY WINDY SUSTAINED
EAST TO SOUTHEAST WINDS SPREADING ACROSS OUR CWA FROM THE EAST
TONIGHT, WHICH SHOULD HELP MOISTEN THINGS UP OVER THE NEXT 24
HOURS.
HOWEVER, THIS AFTERNOON THE LOWER LEVELS WILL STILL REMAIN DRY
(INCLUDING THE EASTERN PORTIONS OF THE CWA). THERE IS AMPLE MID-
LEVEL MOISTURE TO OUR EAST TO ALLOW FOR ISOLATED TO LOW-END
SCATTERED THUNDERSTORMS TO DEVELOP ALONG THE SOUTHERN PORTIONS OF
THE RIM AND SW NM THIS AFTERNOON. GIVEN THE LOCATION OF THE UPPER
HIGH, THESE STORMS WILL MOVE SW INTO OUR EASTERN CWA THIS
AFTERNOON AND THIS EVENING. GIVEN THE DRY SUB-CLOUD LAYER, THE
THREAT FOR EVAPORATING DOWNDRAFTS TO PRODUCE DAMAGING OUTFLOW
WINDS IS PRESENT THIS AFTERNOON. IN FACT...THE LATEST 30/12Z HREF
INDICATES A 40-KM NEIGHBORHOOD PROBABILITY OF 70-90% OUTFLOW
WINDS WILL BE IN EXCESS OF 30+ KTS ACROSS COCHISE, GRAHAM AND
GREENLEE COUNTIES, WITH A 10-30% CHANCE OF GUSTS 50+ KTS. THIS IS
SIMILAR TO WHAT WAS OBSERVED WITH THE 30/00Z HREF. GIVEN THIS, I
FELT CONFIDENT ENOUGH THAT THAT WE WILL SEE BLOWING DUST ISSUES
EAST OF TUCSON TODAY TO ISSUE A BLOWING DUST ADVISORY FOR THE
POTENTIAL FOR VISIBILITY TO GET DOWN TO 1/4-TO-1 MILE IN BLOWING
DUST. ANY OF THE STORMS THAT ARE ENHANCED BY THE LEADING EDGE OF
THE FRONTAL BOUNDARY MOVING IN FROM THE EAST LATE THIS AFTERNOON
AND THIS EVENING WILL ESPECIALLY BE PROBLEMATIC FOR STRONGER WIND
GUSTS GIVEN MOMENTUM TRANSFER.
I HAVE MAINLY BEEN TALKING ABOUT THE EASTERN LOCATIONS OF SOUTHEAST
ARIZONA, BUT THE POTENTIAL ALSO EXISTS FOR SOME OF THE MID-LEVEL
MOISTURE/STORMS TO PUSH WESTWARD IMPACTING EASTERN PIMA AND
SOUTHEAST PINAL COUNTIES WITH STRONG OUTFLOWS/BLOWING DUST. MY
CONFIDENCE ON THAT IS RATHER LOW THOUGH GIVEN HOW STACKED THE 500
AND 300 MB HIGHS ARE AS YOU GET FARTHER WEST. IT SHOULD BE TOO
STABLE TO REINFORCE THE SFC OUTFLOWS...BUT POSSIBLE NONE-THE-LESS.
OTHERWISE, STILL EXPECTING AN ACTIVE WEEK AHEAD.
PREV DISCUSSION
/ISSUED 251 AM MST MON JUN 30 2025/
AN ACTIVE WEEK FOR SOUTHEAST ARIZONA AS MONSOON 2025 RAMPS UP.
FIRST, LET'S TALK ABOUT THE EXTREME HEAT TODAY AS WE TYPICALLY
HAVE A BOUT OF VERY HOT TEMPERATURES BEFORE THE MONSOONAL MOISTURE
COMES IN FULL FORCE AND THIS YEAR IS NO EXCEPTION. TODAY WILL BE
THE HOTTEST DAY WITH A FORECAST HIGH OF 111 DEGREES IN TUCSON.
THIS IS JUST BELOW THE DAILY RECORD OF 112 (1989). AN EXTREME HEAT
WARNING REMAINS IN EFFECT TODAY FOR PIMA, SE PINAL AND THE UPPER
GILA VALLEY REGION OF GRAHAM COUNTY. A DOWNWARD TREND IN
TEMPERATURES STARTS TUESDAY WITH SIGNIFICANT COOLING AND WELL
BELOW NORMAL TEMPERATURES BY THURSDAY.
THE MID/UPPER LEVEL HIGH RESPONSIBLE FOR THE HOT TEMPERATURES IS
SHIFTING TO NORTHEAST AZ TODAY AND THAT IS OPENING DOOR FOR MOISTURE
TO MOVE IN FROM THE EAST. MOISTURE LEVELS TODAY ARE TYPICAL FOR AN
EARLY SEASON TRANSITION DAY AS PWAT VALUES ARE JUST HIGH ENOUGH (0.7-
1 INCH) FOR VERY HIGH BASED CONVECTION. THIS WILL GENERALLY BE
FOCUSED ON LOCALES ACROSS GRAHAM/GREENLEE/COCHISE/SANTA CRUZ
COUNTIES WHERE ISOLATED TO SCATTERED CONVECTION WILL DEVELOP THIS
AFTERNOON. WITH DCAPE VALUES AT 1500-2000+ J/KG WE ARE CONCERNED
ABOUT DRY MICROBURST POTENTIAL WITH ANY STORMS THAT DEVELOP. THE 00Z
HREF CONTINUES TO SHOW 40KM NEIGHBORHOOD PROBABILITIES OF 70 TO 90
PERCENT OF WIND GUSTS GREATER THAN 30 KTS ACROSS
GRAHAM/GREENLEE/COCHISE COUNTIES LATE THIS AFTERNOON AND EARLY
EVENING WITH A 10 TO 30 PERCENT CHANCE OF 50 KTS. NOTE THAT DUE TO
THE LACK OF WETTING RAINS WITH THE CONVECTION, ESPECIALLY AWAY FROM
THE NM BORDER, SOME OF THIS ACTIVITY WILL BE ACCOMPANIED BY DRY
LIGHTNING. BLOWING DUST FROM OUTFLOW WINDS WILL ALSO OCCUR IN
SUSCEPTIBLE LOCALES. TUCSON IS ON THE WESTERN EDGE OF CONVECTIVE
ACTIVITY POTENTIAL LATE THIS AFTERNOON AND THIS EVENING, HOWEVER,
GUSTY OUTFLOW WINDS ARE EXPECTED TO MOVE IN FROM THE EAST OR
NORTHEAST THIS EVENING BRINGING WITH IT AN ADDITIONAL PUSH OF
MOISTURE.
AS PWAT VALUES INCREASE BY TUESDAY MORNING TO AROUND 1 TO 1.1 INCHES
AND CORRESPONDING SURFACE DEWPOINTS JUMP INTO THE 50S THAT WILL SET
THE STAGE FOR AN EXPANSION WESTWARD OF SHOWER AND THUNDERSTORM
CHANCES COMPARED TO TODAY. THE MAIN THREATS ON TUESDAY WILL BE
SIMILAR TO TODAY WITH REGARD TO STRONG AND GUSTY WINDS WITH BLOWING
DUST POTENTIAL DUE TO A CONTINUED DEEP MIXED LAYER WITH HOT SURFACE
TEMPERATURES AND ELEVATED DCAPE VALUES (~1500 J/KG). HOWEVER, WITH
INCREASED MOISTURE THERE WILL BE MORE IN THE WAY OF WETTING RAINFALL
UNDERNEATH THE STORM CORES AREAWIDE.
FOR WEDNESDAY AND THURSDAY A MUCH MORE ROBUST MOISTURE PUSH MOVES IN
WITH THE AID OF A GULF SURGE AND DEEP MOISTURE MOVING NORTH FROM
SONORA. ENSEMBLE MEANS HAVE BACKED OFF SLIGHTLY ON PWAT LEVELS
DURING THIS TIME COMPARED TO 24 HOURS AGO BUT STILL HIGHLY CONFIDENT
OF WIDESPREAD 1.2 TO 1.4 INCHES WITH BRIEF PERIODS UP TO AROUND 1.6
INCHES. THESE VALUES ARE MUCH MORE TYPICALLY SEEN DURING THE PEAK OF
THE MONSOON. WITH WEAK STEERING FLOW ON WEDNESDAY AS THE TROUGH TO
OUR WEST WON'T HAVE MUCH INFLUENCE YET, SOME OF THE STORMS WILL BE
CAPABLE OF PRODUCING LOCALLY HEAVY RAIN AND ISOLATED FLASH FLOODING.
THE AFOREMENTIONED TROUGH AXIS WILL THEN MOVE THROUGH THE STATE
THURSDAY INTO THURSDAY NIGHT, LIKELY PROVIDING A BIT MORE LIFT FOR
AS THE STEERING FLOW BECOMES MORE WEST TO SOUTHWEST. THIS TYPE OF
PATTERN WOULD RESULT IN THE BULK OF THE THUNDERSTORM ACTIVITY FROM
TUCSON EASTWARD BUT STILL CONSIDERABLE UNCERTAINTY REMAINS IN THE
DETAILS.
WITH WESTERLY FLOW ON FRIDAY AND THE HIGH BRIEFLY RETREATING TO OUR
SOUTH TO SOUTHEAST, THE ATMOSPHERE WILL DRY OUT A BIT COMPARED TO
WEDNESDAY AND THURSDAY WHICH WILL REDUCE THUNDERSTORM COVERAGE.
HOWEVER, SHOWER AND THUNDERSTORM CHANCES ARE STILL IN THE 20 TO 40
PERCENT RANGE FOR MUCH OF SOUTHEAST ARIZONA WITH THE HIGHEST POPS
ALONG THE INTERNATIONAL BORDER. PWAT VALUES WILL DROP DOWN TO AROUND
1 INCH THIS WEEKEND RESULTING IN MORE ISOLATED STORM COVERAGE.
AVIATION
VALID THROUGH 01/18Z. GENERALLY SKC THIS MORNING THEN
SCT-BKN CLOUDS 8-13K FT AGL FROM 30/19Z THRU 01/06Z AND THEN
DIMINISHING THRU THE END OF THE VALID PERIOD. SFC WINDS LIGHT AND
VARIABLE THIS MORNING, THEN BECOMING WLY/NWLY FOR KTUS/KOLS
WESTWARD AT 6-10 KTS WHILE REMAINING ELY/SELY FOR KDUG. SFC WINDS
BECOME ELY AT 10-15 KTS WITH GUSTS 20-25 KTS FOR ALL TERMINALS AFT
01/03Z THRU THE END OF THE VALID PERIOD. ADDITIONALLY, EXPECT
ISOLATED -SHRA/-TSRA BETWEEN 30/20Z TO 01/03Z EAST OF KTUS. STORMS
THAT DEVELOP WILL PRODUCE GUSTY OUTFLOW WINDS GREATER THAN 30 KTS
WITH REDUCED VISIBILITY DUE TO LOCALIZED BLDU. AVIATION DISCUSSION
NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
HOT TODAY WITH MINIMUM RELATIVE HUMIDITIES FROM 10
TO 20 PERCENT. THERE IS ENOUGH MID LEVEL MOISTURE FOR ISOLATED TO
SCATTERED MAINLY DRY THUNDERSTORMS ESPECIALLY ACROSS COCHISE, GRAHAM
AND GREENLEE COUNTIES THIS AFTERNOON AND THIS EVENING. THESE WILL
PRODUCE GUSTY OUTFLOW WINDS UP TO AROUND 50 MPH. AS ADDITIONAL
MOISTURE MOVES IN TUESDAY, MIN RH'S INCREASE TO 15 TO 30 PERCENT
WITH ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS FOR MOST OF
SOUTHEAST ARIZONA. THERE WILL BE AN INCREASE IN WETTING RAIN UNDER
THE STORM CORES TUESDAY COMPARED TO TODAY. EVEN HIGHER MOISTURE
LEVELS MOVE IN FOR WEDNESDAY AND THURSDAY WHEN SOME OF THE
THUNDERSTORMS HAVE THE POTENTIAL FOR LOCALLY HEAVY RAIN. SOME DRYING
WILL TEND TO LOWER THUNDERSTORM CHANCES TO AROUND 20 TO 40 PERCENT
FRIDAY INTO THE WEEKEND. WINDS GENERALLY LIGHT AND UNDER 15 MPH
WITH ISOLATED GUSTS UP TO AROUND 50 MPH IN/NEAR ANY THUNDERSTORMS.
TWC WATCHES/WARNINGS/ADVISORIES
EXTREME HEAT WARNING UNTIL 8 PM MST THIS EVENING FOR AZZ501-502-
504>506-509.
BLOWING DUST ADVISORY FROM 1 PM THIS AFTERNOON TO 10 PM MST THIS
EVENING FOR AZZ507>509.
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