968
FXUS65 KFGZ 050348
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
848 PM MST SUN MAY 4 2025
SYNOPSIS
A LARGE AREA OF LOW PRESSURE WILL BRING COOLER
TEMPERATURES AND INCREASED CHANCES FOR PRECIPITATION TODAY THROUGH
WEDNESDAY. WARM AND DRY WEATHER FORECAST TO RETURN THURSDAY ONWARD.
UPDATE
A NARROW TONGUE OF MOISTURE IS GRADUALLY EXPANDING NORTHWARD
FROM THE LOWER DESERTS INTO NORTHERN ARIZONA AHEAD OF A CLOSED-
LOW NEAR YUMA. THE NEXT BATCH OF SHOWERS AND THUNDERSTORMS LOOKS
TO RE- DEVELOP LATER THIS EVENING AND OVERNIGHT ACROSS EASTERN
ARIZONA, THEN SPREAD WESTWARD AS THE CORE OF THE LOW MOVES INTO
NORTHERN ARIZONA. ACROSS THE WESTERN POTIONS OF THE STATE, MODEL
SOUNDINGS SHOW A VERY DEEPLY SATURATED PROFILE, THUS LEADING TO
LIKELY VERY EFFICIENT PRECIPITATION GOING INTO MONDAY. THE EXACT
BULLSEYE OF THE HEAVIEST PRECIPITATION HAS WAVERED A BIT, BUT AS
OF NOW MUCH OF THE HI-RES GUIDANCE POINTS TOWARDS THE GREATEST
CHANGES BEING MAINLY WEST OF THE US-89/I-17 CORRIDOR. HI-RES
GUIDANCE HAS SEVERAL AREAS OF 0.75-1.00 INCHES OF QPF, WITH SOME
HIGHER AMOUNTS POSSIBLE. IT IS IMPORTANT TO NOTE THOUGH THAT MOST
AREAS WILL NOT SEE THAT MUCH AS MUCH OF THE PRECIPITATION IS
EXPECTED TO REMAIN CONVECTIVE IN NATURE AS OPPOSED TO A WIDESPREAD
STRATIFORM RAIN EVENT. THE BULK OF THE AREA LOOKS TO FALL INTO
MAINLY AROUND A FEW HUNDREDTHS TO A TENTH IN THE MORE RAIN-
SHADOWED AREAS TO AROUND 0.30-0.50 INCHES IN THE HIGHER TERRAIN.
THE OTHER IMPORTANT DETAIL IS THAT WITH THE COLD CORE OF THE LOW
OVERHEAD, SNOW LEVELS WILL FALL BACK TO AROUND 6500 FEET AND
POTENTIALLY A BIT LOWER IN THE HEAVIEST PRECIPITATION. THUS, AREAS
ACROSS THE HIGHEST ELEVATIONS COULD POTENTIALLY SEE SNOW DURING THE
DAY MONDAY. HOWEVER, SURFACE TEMPERATURES ARE EXPECTED TO REMAIN
RIGHT AT FREEZING (OUTSIDE OF THE HIGHEST MOUNTAIN PEAKS ABOVE 8000
FEET), SO EFFICIENT SNOW ACCUMULATION LOOKS UNLIKELY. NEVERTHELESS,
SOME BRIEFLY ACCUMULATION SNOW AND REDUCED VISIBILITY IN ANY HEAVIER
SNOW SHOWER WILL BE POSSIBLE IN THE HIGH COUNTRY.
MINOR UPDATES THIS EVENING FOR CURRENT TRENDS AND LATEST HI-RES
GUIDANCE. PREVIOUS DISCUSSION CONTINUES BELOW.
PREV DISCUSSION /446 PM MST/
A DEEP AND COLD UPPER LOW (FOR
MAY) IS NOW NEAR IMPERIAL AND WILL MOVE EASTWARD TODAY AND TONIGHT,
BEFORE SLOWING DOWN AND SPLITTING ON MONDAY. THE LOW THEN RECONSOLIDATES
NEAR THE FOUR CORNERS MONDAY NIGHT AND TUESDAY, WHILE FILLING AND
WARMING. A TRAILING LOW MOVES INTO THE TROUGH POSITION OVER ARIZONA
ON WEDNESDAY.
THIS IS A COMPLICATED PATTERN, WITH MANY DIFFERENT ASPECTS TO LOOK
AT. CONVECTION AHEAD OF THE LOW TODAY IS PRODUCING A FEW STRONGER
THUNDERSTORMS, WHILE PRECIPITATION TONIGHT MAY ENHANCE ALONG A COLD
FRONT. THEN, WRAPAROUND PRECIPITATION AFFECTS THE AREA MONDAY AND
MONDAY NIGHT, WITH CONVECTIVE ELEMENTS CONTINUING INTO TUESDAY. THE
TRAILING LOW WILL MOVE INTO A MOIST AIR MASS WEDNESDAY, WITH MORE
POTENTIALLY SIGNIFICANT CONVECTION BREAKING OUT.
ADDITIONALLY, WE WILL HAVE GUSTY PRE-FRONTAL WINDS TODAY, BUT OUR
RELATIVE HUMIDITY LEVELS AND WIND SPEEDS AVOIDS THE NEED FOR ANY
HEADLINES. SNOW LEVELS IN THE CORE OF THE LOW LATER TONIGHT AND
MONDAY WILL PRODUCE AREAS OF SNOW ABOVE 6500-7500 FEET, WITH A FEW
BRIEF TROUBLE SPOTS POSSIBLE FROM FLAGSTAFF WESTWARD.
WHEN THIS IS ALL SAID AND DONE, MANY AREAS THROUGH WESTERN AND
CENTRAL ARIZONA MAY SEE QPF AMOUNTS FROM 1-2". ANOTHER LATE SEASON
GIFT THAT MAY ALLOW US TO AVOID A DANGEROUS FWX SEASON BEFORE THE
MONSOON ARRIVES IN LATE JUNE.
AVIATION...MONDAY 05/00Z THROUGH TUESDAY 06/00Z
SCT -TSRA WILL
CONTINUE THROUGH 02Z, WITH THUNDER BECOMING MOSTLY ISOLATED
THEREAFTER. SCT -SHRA WILL CONTINUE FROM 02-10Z, THEN A STEADY
REGION OF RA AND HIGH ELEVATION SN WILL FORM PRIMARILY TO THE WEST
OF NAVAJO COUNTY. SCT -SHRA WILL CONTINUE ELSEWHERE. MVFR
CONDITIONS ARE EXPECTED, AND REGIONS OF IFR-LIFR CIGS COULD
PERSIST THROUGH 00Z TUESDAY. WINDS ARE LIGHT AND VRB OVERNIGHT AND
SW 10-15 KTS TOMORROW. GUSTY AND RAPIDLY CHANGING WIND ARE
POSSIBLE NEAR SHOWERS.
OUTLOOK...TUESDAY 06/00Z THROUGH THURSDAY 08/00Z...CONTINUED
AREAS OF -SHRA/-SHSN AND SOME ISOLATED -TSRA THROUGHOUT THE
PERIOD, WITH THE HIGHEST COVERAGE THROUGH 12Z WED. WIDESPREAD MVFR
WITH AREAS IFR/LIFR THROUGH TUESDAY MORNING, THEN AREAS MVFR
THEREAFTER. WINDS ARE W-NW 5-10 KTS ON TUESDAY AND WEDNESDAY.
GUSTY AND RAPIDLY CHANGING WIND ARE POSSIBLE NEAR SHOWERS.
FIRE WEATHER...TONIGHT THROUGH TUESDAY
COOLER WITH SHOWERS AND
THUNDERSTORMS AT TIMES. ACCUMULATING SNOW POSSIBLE ABOVE 6500-7000
FEET LATE TONIGHT AND MONDAY. SOUTH-SOUTHWEST WINDS 15-20 MPH WITH
GUSTS TO 25-35 MPH THROUGH EARLY THIS EVENING. WEST-SOUTHWEST WINDS
DECREASE TO 10-15 MPH MONDAY AND TUESDAY.
WEDNESDAY THROUGH FRIDAY...COOL AND SHOWERY WEATHER CONTINUES
WEDNESDAY WITH A FEW THUNDERSTORMS ALSO POSSIBLE. BECOMING DRY AND
MUCH WARMER THURSDAY AND FRIDAY. WINDS WEST-NORTHWEST 5-15 MPH ON
WEDNESDAY, LIGHT AND VARIABLE TO NORTHEAST THURSDAY AND FRIDAY.
FGZ WATCHES/WARNINGS/ADVISORIES
NONE.
PUBLIC...HUMPHREYS/PETERSON
AVIATION...LEWANDOWSKI
FIRE WEATHER...JJ
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF
CLICK HERE TO GO TO PREVIOUS BULLETINS.
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