Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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000
FXUS65 KFGZ 282213
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
310 PM MST SUN DEC 28 2014

.SYNOPSIS...COLD AND DRY WEATHER WILL CONTINUE THROUGH AT LEAST
MONDAY AND INTO TUESDAY FOR NORTHEASTERN ARIZONA. A POTENTIALLY
SIGNIFICANT STORM IS BREWING UP WINTER WEATHER FOR WEDNESDAY THROUGH
FRIDAY. THE PEAK SNOWFALL WILL LIKELY OCCUR ON WEDNESDAY AND
THURSDAY. PLAN FOR SIGNIFICANT SNOW ACCUMULATIONS AND WINTER DRIVING
CONDITIONS ABOVE 5000 FEET ELEVATION FOR YOUR NEW YEARS TRAVEL
PLANS. DRIER WEATHER RETURNS JUST IN TIME FOR NEXT WEEKEND. KEEP
UPDATED ON OUR WEATHER FORECAST FOR THIS EVENT AS IMPACTS MAY EVOLVE
OVER TIME.

&&

.DISCUSSION...NORTHWESTERLY FLOW ALOFT WILL KEEP NORTHERN ARIZONA IN
A COLD AN DRY WEATHER PATTERN THROUGH AT LEAST MONDAY AND INTO
TUESDAY FOR CENTRAL AND EASTERN ARIZONA. BREEZY WINDS WILL ALSO
DEVELOP EACH DAY AHEAD OF AN APPROACHING WINTER STORM SYSTEM.

A SIGNIFICANT STORM IS BREWING UP WINTER WEATHER IMPACTS FOR ARIZONA
FROM WEDNESDAY THROUGH FRIDAY. OVER THE NEXT SEVERAL DAYS THIS STORM
SYSTEM WILL RETROGRADE SLOWLY SOUTHWESTWARD THROUGH NEVADA AND
CALIFORNIA BEFORE HOOKING EASTWARD ACROSS THE SOUTHWEST REGION. THIS
STORM TRACK WILL CUT OFF THE LOW FROM THE MAIN STEERING FLOW (POLAR
JET STREAM) SLOWING DOWN THE STORMS MOTION AND CAUSING THE CUT OFF
LOW TO DRIFT EASTWARD IN WEAK STEERING FLOW.

THE OPERATIONAL MODELS ARE CURRENTLY DRIVING THE STORM DIRECTLY
EASTWARD INTO THE MOGOLLON RIM WHICH IS A FAVORABLE SOLUTION FOR
EFFICIENT RAIN AND SNOW PRODUCTION. HIGHER MODEL CONSISTENCY IS
IMPROVING OUR CONFIDENCE ON SIGNIFICANT SNOW AMOUNTS WITH AROUND 4
TO 8 INCHES OF SNOWFALL IN THE FORECAST WITH LOCALLY HIGHER AMOUNTS
OVER UPSLOPE TERRAIN FAVORED LOCATIONS. THE GOOD NEWS ON THE
CONSISTENCY FRONT IS THE GFS ENSEMBLE HAS TIGHTENED UP ON THE STORM
TRACK VARIABILITY. THE ENSEMBLE OF 12 MODEL MEMBERS USING DIFFERENT
INITIAL CONDITIONS IS NOW MORE SIMILAR TO THE CURRENT OPERATIONAL
MODELS (GFS...ECMWF...GEM). THIS STORM FORECAST IS STILL NOT A SLAM
DUNK AS FAR AS SNOW AMOUNTS AND SUBTLE SHIFTS IN TRACK CAN MAKE BIG
IMPACTS ON AMOUNTS. FOR EXAMPLE...THE AMERICAN GFS MODEL IS
CURRENTLY RUNNING 6 TO 12 HOURS BEHIND THE EUROPEAN ECMWF MODEL ON
THE ARRIVAL OF THE HEAVIEST PRECIPITATION BAND.

PLAN FOR SIGNIFICANT SNOW ACCUMULATIONS AND WINTER DRIVING
CONDITIONS ABOVE 5000 FEET ELEVATION FOR YOUR NEW YEARS TRAVEL
PLANS. FOR NOW...WE ANTICIPATE THE NEED FOR AT LEAST A WINTER
WEATHER ADVISORY AND/OR A WINTER STORM WATCH TO BE ISSUED IN THE NEXT
FEW DAYS. TIMING WISE WE ARE NOT YET IN THE WINDOW FOR WINTER
WEATHER PRODUCT ISSUANCE. KEEP UPDATED ON THE LATEST FORECAST AS
WINTER IMPACTS TO YOUR LOCATION MAY CHANGE OVER TIME.

&&

.AVIATION...FOR THE 00Z PACKAGE...EXPECT VFR CONDITIONS AND MAINLY
CLEAR SKIES OVER THE NEXT 24 HOURS. SOUTHWEST WINDS 5 TO 15 KTS
MONDAY AFTERNOON. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

PUBLIC.........BOHLIN
AVIATION.......MCCOLLUM

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF




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