778
FXUS65 KFGZ 271111
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
411 AM MST SUN SEP 27 2026
SYNOPSIS
SHOWER AND THUNDERSTORM CHANCES WILL INCREASE SLIGHTLY
THIS AFTERNOON AND CONTINUE TO INCREASE OVERNIGHT, WITH
WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORM MONDAY. THIS IS
ASSOCIATED WITH AN INCOMING TROUGH FROM THE WEST COAST THAT WILL
INTERACT WITH TROPICAL MOISTURE AND POTENTIALLY BRING HEAVY RAIN,
STRONG THUNDERSTORMS AND POSSIBLE FLASH FLOODING. A FLASH FLOOD
WATCH HAS BEEN ISSUED FOR MONDAY AND TUESDAY WHICH IS THE TIME
PERIOD WHEN THE HEAVIEST RAIN IS LIKELY TO OCCUR. SHOWER AND
THUNDERSTORM CHANCES WILL THEN DECREASE WEDNESDAY AND WEDNESDAY
NIGHT, WITH DRY AND WARM CONDITIONS TO START OFF OCTOBER.
DISCUSSION
MOISTURE FROM TROPICAL CYCLONES ODALYS AND POLO WILL BEGIN
OVERSPREADING THE AREA, MOST LIKELY IN THE HIGH AND MID LEVELS AT
FIRST WHICH WILL INCREASE CLOUD COVER TODAY, WITH SOME LIGHT RAIN
STARTING THIS AFTERNOON. THE LOWER LEVELS WILL BE DRY AT FIRST
BUT START MOISTENING UP FROM THESE INITIAL RAIN SHOWERS. THE
POTENTIAL FOR SHOWERS AND THUNDERSTORMS WILL CONTINUE TO INCREASE
OVERNIGHT AS MOISTURE CONTINUES TO INCREASE ACROSS AZ.
BY MONDAY A DEEP WEST COAST TROUGH APPROACHES WITH A CLOSED UPPER-
LEVEL LOW EXPECTED TO DEVELOP AT ITS BASE, THEN SLOWLY MOVE
ACROSS THE REGION TUESDAY. THIS TROUGH WILL ACT UPON THE TROPICAL
MOISTURE ALREADY IN PLACE AND LIFT FROM THE APPROACHING TROUGH
WILL GENERATE SOME EMBEDDED THUNDERSTORMS THAT COULD BECOME STRONG
TO SEVERE AT TIMES WITH HEAVY RAIN, STRONG WINDS AND SOME LARGE
HAIL. WPC CONTINUES TO MESSAGE A MODERATE RISK FOR EXCESSIVE
RAINFALL FOR MOST OF THE REGION FOR MONDAY AND THEN SHIFTING FOCUS
FOR THE EASTERN PART OF THE STATE TUESDAY AS THE TROUGH AND
CLOSED UPPER-LEVEL LOW MOVE EASTWARD. A FLOOD WATCH REMAINS IN
EFFECT FOR MONDAY AND TUESDAY.TEMPERATURES ACROSS THE REGION
MONDAY AND TUESDAY WILL BE QUITE COOL DUE TO THE CLOUD COVER AND
RAINFALL, ABOUT 10 DEGREES BELOW AVERAGE. BY WEDNESDAY NIGHT
PRECIPITATION CHANCES SHOULD START WINDING DOWN IN THE FAR EASTERN
PARTS OF THE STATE AS THE TROUGH SWEEPS EAST AND TAKES THE
MOISTURE PLUME WITH IT.
ONE THING TO NOTE: DESPITE THE FACT THE TROPICAL MOISTURE IS
COMING FROM TWO TROPICAL CYCLONES TO THE SOUTH, NEITHER ONE OF
THESE CIRCULATIONS WILL ACTUALLY MAKE IT UP INTO ARIZONA. ODALYS
IS LOOPING SOUTH AND WILL LIKELY DIE IN THE OPEN OCEAN, POLO IS
EXPECTED TO MAKE LANDFALL IN BAJA CALIFORNIA, CROSS THE GULF OF
CALIFORNIA AND BREAK APART TO OUR SOUTH WHEN IT MAKES LANDFALL
AGAIN IN MAINLAND MEXICO. THE STRONG TROUGH AND UPPER-LEVEL LOW
MOVING IN FROM THE WEST AND ACTING ON THAT TROPICAL MOISTURE DRAWN
NORTH WILL BE THE SOURCE OF THE ACTIVE WEATHER MONDAY AND
TUESDAY.
BY THURSDAY ONWARD DRY AIR FROM THE WEST AND NORTH WILL TAKE OVER
AND LIMIT THE POTENTIAL FOR PRECIPITATION THROUGH THE REST OF THE
WEEK. SOME RIDGING WILL MOVING IN TOWARDS THE END OF THE WEEK
LOOK FOR A PLEASANT START TO OCTOBER AS HIGH TEMPERATURES RECOVER
TO A FEW DEGREES ABOVE AVERAGE.
AVIATION...SUNDAY 27/12Z THROUGH MONDAY 28/12Z
MAINLY VFR
CONDITIONS, WITH MVFR CONDITIONS POSSIBLE LATE THIS AFTERNOON AND
TONIGHT. LOOK FOR INCREASING CLOUDS TODAY WITH SOUTHWEST WINDS
10-15 KTS AND GUSTS TO 20 KTS DEVELOPING AFTER 18Z. A CHANCE OF
SHOWERS AND THUNDERSTORMS ALONG AND NORTH OF A KPAN-KINW-OV7 LINE
LATE SUNDAY AFTERNOON AND INCREASING ACROSS THE REGION OVERNIGHT.
GUSTY AND ERRATIC WINDS NEAR STORMS.
OUTLOOK...MONDAY 28/12Z THROUGH WEDNESDAY 30/12Z...AREAS OF MVFR
CONDITIONS DEVELOPING IN SCATTERED TO NUMEROUS SHRA/TSRA. DAYTIME
WINDS SOUTH 10-20 KTS ON MONDAY BECOMING NORTH TO NORTHEAST AT
5-15 KTS ON TUESDAY. GREATEST COVERAGE OF SHOWERS AND
THUNDERSTORMS START TO BECOME MORE FOCUS OVER EASTERN AZ TUESDAY
NIGHT. OVERNIGHT WINDS GENERALLY LIGHT AND VARIABLE.
FIRE WEATHER...TODAY THROUGH MONDAY
DRY CONDITIONS ARE EXPECTED
THIS MORNING, WITH A SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS
THIS AFTERNOON. PRECIPITATION CHANCES WILL RAMP UP OVERNIGHT
TONIGHT WITH WIDESPREAD WETTING RAIN AND EMBEDDED THUNDERSTORMS
ON MONDAY, PRESENTING A MODERATE FLOOD RISK. LIGHT WINDS THIS
MORNING WILL BECOME S-SW AT 10-15 MPH GUSTING TO 25 MPH THIS
AFTERNOON, AND S 5-15 MPH ON MONDAY.
TUESDAY THROUGH THURSDAY...PROLONGED WIDESPREAD PRECIPITATION
CHANCES CONTINUE INTO TUESDAY NIGHT AS AN APPROACHING WEATHER SYSTEM
COMBINES WITH TROPICAL MOISTURE. PRECIPITATION CHANCES DECLINE FROM
WEST TO EAST WEDNESDAY AND WEDNESDAY NIGHT. THERE IS A THREAT OF
HEAVY RAINFALL AND FLASH FLOODING ON TUESDAY FOR ALL OF NORTHERN AZ.
WINDS N-NE 10-20 MPH ON TUESDAY, THEN NW-N 5-15 MPH ON WEDNESDAY AND
THURSDAY.
FGZ WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH FROM THIS EVENING THROUGH TUESDAY EVENING FOR
AZZ004>018-037>040.
PUBLIC...SCHANK
AVIATION...SCHANK
FIRE WEATHER...SCHANK
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page