742
FXUS65 KTWC 171732
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
1032 AM MST THU SEP 17 2026
SYNOPSIS
LINGERING SHOWERS THIS MORNING WITH A CHANCE OF
STORMS ALONG THE ARIZONA AND NEW MEXICO BORDER THIS AFTERNOON
AND EVENING. DRIER CONDITIONS MOVE IN FRIDAY LIMITING THE DAILY
CHANCE THROUGH THIS WEEKEND INTO EARLY NEXT WEEK. HIGH
TEMPERATURES WILL BE BELOW NORMAL TODAY, THEN BE AROUND NORMAL
FRIDAY INTO EARLY NEXT WEEK.
UPDATE 1025 AM
AFTER SOME PATCHY FOG IN HIGHER ELEVATION VALLEYS EAST OF
TUCSON, MOSTLY SUNNY SKIES ARE TAKING HOLD. SFC MOISTURE REMAINS
HIGH, BUT PWATS HAVE DROPPED SUBSTANTIALLY THIS MORNING. FORCING
HAS ALSO LARGELY EXITED THE REGION, WITH THE EXCEPTION OF AZ/NM
BORDER FOR THIS AFTERNOON. ISOLATED TO PERHAPS SCATTERED
ACTIVITY IS EXPECTED THIS AFTERNOON INTO EARLY EVENING. WHILE
COVERAGE AND INTENSITY SHOULD BE LESS, ENOUGH
MOISTURE/INSTABILITY AND FLOW COULD PRODUCE A COUPLE STRONGER
STORMS WITH GUSTY WINDS, SMALL HAIL, AND LOCALLY HEAVY RAIN.
THIS WILL ALL BE EAST OF TUCSON AND FOCUSED NEAR/ALONG THE AZ/NM
BORDER. IT IS NOT OUT OF THE QUESTION WE COULD SEE SOME MINOR
ISSUES OR AN ISOLATED AND LOCALIZED FLASH FLOOD THREAT OVER ANY
AREAS THAT HAVE RECEIVED HVY RAIN OVER THE PAST FEW DAYS.
REST OF FORECAST IS ON TRACK.
DISCUSSION
THE TROPICAL LOW THAT BROUGHT WIDESPREAD RAINS TO
SOUTHEAST ARIZONA YESTERDAY HAS OPENED UP TO A SHORT-WAVE
TROUGH AND IS MOVING NE INTO NORTHEAST ARIZONA THIS MORNING IN
ADVANCE OF AN UPPER LOW THAT WAS OVER NORTHERN CALIFORNIA. RADAR
SHOWED ISOLATED TO SCATTERED LIGHT SHOWERS ACROSS EASTERN HALF
OF FORECAST AREA. THESE SHOWERS SHOULD END FROM SOUTH TO NORTH
BY SUNRISE. WITH SURFACE RH VALUES IN THE 90-100 PERCENT RANGE,
SOME PATCHY FOG, BRIEFLY DENSE, MAY DEVELOP BEFORE SUNRISE IF
THERE IS SOME CLEARING.
FOR TODAY: DRY ACROSS MOST OF THE FORECAST AREA. THE EXCEPTION
WILL BE NEAR/ALONG THE AZ/NM BORDER THIS AFTERNOON WITH A CHANCE
OF SHOWERS AND THUNDERSTORMS EXIST.
TONIGHT INTO FRIDAY: THE SHORT-WAVE TROF THAT IS CURRENTLY OVER
CENTRAL BAJA WILL LIFT NE ACROSS THE AREA LATER TONIGHT INTO
FRIDAY. ALTHOUGH THE DYNAMICS WITH THIS FEATURE IS WEAK, CAN'T
RULE OUT ISOLATED LIGHT SHOWERS.
THIS WEEKEND THROUGH MONDAY: DRIER AIR FINALLY BEGINS TO FILTER
INTO SOUTHEAST ARIZONA AS FLOW ALOFT SHIFTS MORE WESTERLY. THIS
COULD HELP LIMIT THUNDERSTORM ACTIVITY SOMEWHAT AND KEEP
ACTIVITY MAINLY EAST AND SOUTH OF TUCSON. HIGH TEMPERATURES
RETURN TO AT OR SLIGHTLY ABOVE NORMAL.
TUESDAY AND WEDNESDAY: MOISTURE ADVECTION OUT AHEAD OF A
SOUTHERN STREAM SYSTEM WITH BRING A CHANCE OF AFTERNOON STORMS
TO THE EASTERN ZONES BOTH DAYS.
8 TO 14 DAY OUTLOOKS (THE SEP 24 TO WED SEP 30)
TEMPERATURE: LEANING ABOVE NORMAL, 47-52% CHANCE
PRECIPITATION: LEANING ABOVE NORMAL, 47-52% CHANCE
AVIATION /18Z THURSDAY THROUGH 18Z FRIDAY/
BKN-SCT 4K-6K FT AGL WITH ISOLD -SHRA THRU 17/15Z THEN FEW-SCT
4K-6K FT THRU 17/22Z. SLGT CHC FOR ISOLD -SHRA NR AZ/NM BORDER
BTWN 17/20Z AND 18/02Z. SFC WINDS S-SE LESS THAN 10 KTS.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
LINGERING SHOWERS THIS MORNING WITH A CHANCE OF
STORMS ALONG THE ARIZONA AND NEW MEXICO BORDER THIS AFTERNOON
AND EVENING. DRIER CONDITIONS MOVE IN FRIDAY LIMITING THE DAILY
CHANCE THROUGH THIS WEEKEND INTO EARLY NEXT WEEK. HIGH
TEMPERATURES WILL BE BELOW NORMAL TODAY AND THURSDAY, THEN BE
AROUND NORMAL FRIDAY INTO EARLY NEXT WEEK. MIN RH VALUES MAINLY
20 TO 45 PERCENT IN THE VALLEYS AND 35 TO 65 PERCENT IN THE
MOUNTAINS OVER THE NEXT WEEK. RH RECOVERIES WILL CONTINUE TO BE
EXCELLENT OVERNIGHT. WINDS WILL GENERALLY REMAIN LESS THAN 15
MPH AND TERRAIN DRIVEN. GUSTY AND ERRATIC WINDS WILL ACCOMPANY
THUNDERSTORMS.
TWC WATCHES/WARNINGS/ADVISORIES
NONE.
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