906
FXUS65 KFGZ 181956
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1256 PM MST SUN OCT 18 2026
SYNOPSIS
SHOWER AND THUNDERSTORM CHANCES CONTINUE THROUGH
SUNDAY EVENING AS A WEATHER SYSTEM APPROACHES. THIS ACTIVE
PATTERN CONTINUES THROUGH MOST OF THE WEEK WITH CONTINUED DAILY
SHOWER CHANCES, OCCASIONAL GUSTY WINDS, AND BELOW NORMAL DAYTIME
TEMPERATURES. THE HIGHEST CHANCE OF RAIN WILL BE ON WEDNESDAY AND
THURSDAY.
DISCUSSION...FOR REMAINDER OF SUNDAY THROUGH MONDAY
LOW
PRESSURE LOCATED OVER SOUTHWEST ARIZONA SUNDAY AFTERNOON WILL
SLOWLY TRACK NORTHEASTWARD ACROSS THE STATE, WEAKENING AS IT
GOES. THE LOW WILL DELIVER SCATTERED SHOWERS AND PERHAPS A STRAY
AFTERNOON THUNDERSTORM EACH DAY. HOWEVER, THERE ARE A FEW FACTORS
THAT WILL LIMIT PRECIPITATION AMOUNTS WITH THIS LOW. FIRST, THE
LOW IS WEAK AND WILL GROW WEAKER. SECOND, THE LOW-LEVEL FLOW AND
THUS OROGRAPHIC LIFT WILL BE MINIMAL. THIRD, MAINLY CLOUDY SKIES
WILL LIMIT DAYTIME HEATING AND ASSOCIATED INSTABILITY. AS A
RESULT, GENERALLY LIGHT PRECIPITATION IS ANTICIPATED WITH TOTALS
RANGING FROM TRACE AMOUNTS TO 0.20 INCHES THROUGH MONDAY (THE
HIGHEST MOUNTAIN PEAKS COULD SEE AS MUCH AS 0.50 INCHES). IN ANY
CASE, THIS IS A WARM SYSTEM SO SNOW LEVELS ARE EXPECTED TO REMAIN
PRIMARILY ABOVE 11,000 FEET. LIGHT AND VARIABLE WINDS ON SUNDAY
WILL TURN MORE SOUTHERLY ON MONDAY AS ANOTHER PACIFIC LOW
APPROACHES. THERE WILL BE A COOLING INFLUENCE FROM THE LIGHT
PRECIPITATION AND CLOUDS WITH HIGH TEMPERATURES DROPPING BY AROUND
5 DEGREES ON SUNDAY AND MONDAY COMPARED TO SATURDAY.
ON TUESDAY...THE CURRENT WEAK LOW WILL MOVE TO THE NORTHEAST
IN RESPONSE TO A STRONGER LOW PRESSURE SYSTEM DROPPING SOUTHWARD
FROM THE GULF OF ALASKA. MOISTURE WILL CONTINUE TO LINGER ACROSS
ARIZONA IN ADVANCE OF THIS STRONGER LOW WITH SLIGHT CHANCES FOR
SHOWERS OR A STRAY THUNDERSTORM CONTINUING. ACTIVITY WILL MAINLY
BE CONFINED TO THE AFTERNOON AND EARLY EVENING ASSOCIATED WITH
INSTABILITY INDUCED BY DAYTIME HEATING. SOUTHERLY WINDS WILL
STRENGTHEN TO 10-20 MPH AS THE LOW DRAWS CLOSER TO ARIZONA. HIGH
TEMPERATURES WILL WARM A BIT AS SOUTHERLY FLOW PUSHES A MILD AIR
MASS ACROSS ARIZONA.
FROM WEDNESDAY ONWARD...FORECAST MODELS CONTINUE TO SHOW THE
PACIFIC LOW DIVING SOUTHWARD THEN MOVING ACROSS THE WESTERN
STATES INCLUDING ARIZONA, TAPPING INTO MOISTURE OF SUBTROPICAL (OR
EVEN TROPICAL) ORIGINS. THE RESULT, WIDESPREAD SHOWERS AND LIKELY
A FEW THUNDERSTORMS ARE FORECAST, ESPECIALLY ON WEDNESDAY AND
THURSDAY. THE MOST SUBSTANTIAL MOISTURE WILL LIKELY MOVE ACROSS
ARIZONA FROM ABOUT FLAGSTAFF EASTWARD WHERE LOCAL RAINFALL TOTALS
RANGING FROM 1 TO 3 INCHES WILL BE POSSIBLE. THE AREA OF THE
HIGHEST RAINFALL TOTALS INCLUDES THE WHITE MOUNTAINS, MOGOLLON
RIM, NAVAJO NATION AND GILA COUNTY. FURTHER WEST LOOKING AT
LIGHTER AMOUNTS OF 0.25-0.75 INCHES. THE SNOW LEVEL WILL REMAIN
ELEVATED FOR MUCH OF THE STORM DUE TO THE SUBTROPICAL TO TROPICAL
NATURE OF THE MOISTURE. THE SNOW LEVEL COULD DROP AS LOW AS 8500
FEET AS THE COLDEST TEMPERATURES ALOFT MOVE OVER ARIZONA ON FRIDAY
AND SATURDAY (WHEN SHOWER CHANCES WILL BE RAPIDLY DIMINISHING).
ALSO, PRESSURE GRADIENTS WILL STRENGTHEN ON WEDNESDAY AND THURSDAY
WITH SOUTH TO SOUTHWEST WINDS OF 15-25 MPH GUSTING TO 35 MPH
DEVELOPING. LATER ON FRIDAY AND ON SATURDAY A WEAK LOW WILL LINGER
OVER ARIZONA AND WOULD NOT BE SUPRISED IF AT LEAST A SLIGHT
CHANCE OF SHOWERS LINGERS. HIGH TEMPERATURES WILL BE ON THE
DECREASE UNDER THE INFLUENCE OF PERCEPTION, CLOUDS AND COOLER AIR
ASSOCIATED WITH THE LOW.
AVIATION...SUNDAY 18/18Z THROUGH MONDAY 19/18Z
MAINLY VFR WITH
LOCALIZED MVFR POSSIBLE IN HEAVIER SHOWERS. SCT -SHRA WITH ISO TS
DIMINISHING AFTER 02Z. VARIABLE WINDS 5-10 KTS, BECOMING LIGHT
OVERNIGHT.
OUTLOOK...MONDAY 19/18Z THROUGH WEDNESDAY 21/18Z...MAINLY VFR WITH
BRIEF MVFR IN HEAVIER SHOWERS. SCT -SHRA/-TSRA ALONG THE HIGHER
TERRAIN ON MONDAY AFTERNOON, BECOMING ISO ON TUESDAY. DAYTIME
WINDS S-SW 5-15 KTS ON MONDAY, INCREASING TO 10-20 KTS ON TUESDAY.
EXPECT LIGHT AND VARIABLE WINDS DURING THE OVERNIGHT PERIOD.
FIRE WEATHER...MONDAY THROUGH TUESDAY
COOL CONDITIONS EXPECTED TO
CONTINUE THROUGH THE PERIOD. SOUTH WINDS 5-15 MPH ON MONDAY,
INCREASING TO 10-20 MPH ON TUESDAY. SCATTERED SHOWERS AND
THUNDERSTORMS AGAIN ON MONDAY, WITH A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS ON TUESDAY.
WEDNESDAY THROUGH FRIDAY...COOL TEMPERATURES CONTINUE. SHOWERS AND
THUNDERSTORMS LIKELY ON WEDNESDAY AND THURSDAY WITH MOST AREAS
SEEING WETTING RAINS, THEN SCATTERED ACTIVITY EXPECTED ON FRIDAY.
SOUTH WINDS 15-25 MPH WITH GUSTS 30-40 MPH ON WEDNESDAY AND
THURSDAY, BECOMING SOUTH THROUGH SOUTHWEST 10-20 MPH WITH GUSTS 25-
30 MPH ON FRIDAY.
FGZ WATCHES/WARNINGS/ADVISORIES
NONE.
PUBLIC...MCCOLLUM
AVIATION...MEOLA
FIRE WEATHER...MEOLA
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF
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