Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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000
FXUS65 KFGZ 291121
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
420 AM MST MON DEC 29 2014

.SYNOPSIS...EXPECT COOL AND DRY CONDITIONS TO CONTINUE TODAY AND
TUESDAY...ALONG WITH INCREASING WEST AND SOUTHWEST WINDS. A MAJOR
WINTER STORM WILL IMPACT THE REGION BY WEDNESDAY AND THURSDAY. THIS
STORM WILL BRING ACCUMULATING SNOW TO MUCH THE REGION...WITH THE
HIGHEST AMOUNTS LIKELY ALONG AND SOUTH OF THE MOGOLLON RIM. EXPECT
DANGEROUS DRIVING CONDITIONS FOR THE NEW YEARS HOLIDAY.

&&

.DISCUSSION...A DEEP AND COLD TROUGH OVER THE WESTERN UNITED STATES
IS SHOWING SIGNS OF DEEPENING ALONG THE WESTERN EDGE...ESSENTIALLY
OVER WASHINGTON AND OREGON. A COLD FRONT STRETCHING THROUGH EASTERN
OREGON AND SOUTHEASTWARD THROUGH NEVADA...CENTRAL UTAH/COLORADO IS
ALREADY PRODUCING SNOW TO UR NORTH.

THE S/WV SEEN IN CENTRAL OREGON WILL DIVE SOUTH AND RETROGRADE
SLIGHTLY OVER THE NEXT 48 HOURS...EVENTUALLY CLOSING OFF OVER
CENTRAL AND SOUTHERN CALIFORNIA BY TUESDAY EVENING. THE LOW WILL
THEN DRIFT EASTWARD OR SOUTHEASTWARD THROUGH ARIZONA WEDNESDAY AND
THURSDAY. THIS LOW WILL RETROGRADE FAR ENOUGH WEST TO PICK UP SOME
MARINE LAYER MOISTURE...BUT NOT FAR ENOUGH TO CREATE A MAJOR PACIFIC
INFLUENCE. NONETHELESS...THERE WILL BE ENOUGH FOR OUR FIRST MAJOR
STORM THIS WINTER.

THE COMBINATION OF A SLOW MOVING CLOSED LOW WITH MODERATE UPSLOPE
FLOW AND VERY COLD AIR WILL CREATE LOW SNOW LEVELS AND HIGH SNOW
EFFICIENCY. DESPITE NOT SEEING VERY OVERWHELMING QPF AMOUNTS...WATER
TO SNOW RATIOS WILL BE HIGH ENOUGH TO PRODUCE SOME SIGNIFICANT
ACCUMULATIONS. SNOW LEVELS WILL FALL TO THE VALLEY FLOORS IN THE
CORE OF LOW LATER WEDNESDAY NIGHT AND THURSDAY...BRINGING SNOW TO
AREAS THAT RARELY EXPERIENCE IT.

IT IS STILL A BIT EARLY TO ISSUE ANY HEADLINES...BUT THIS WILL
LIKELY BE A WINTER STORM WARNING LEVEL EVENT. MANY AREAS WILL SEE
ACCUMULATIONS...WITH THE PORTIONS OF CENTRAL ARIZONA OVER 5000 FEET
SEEING THE MOST. AREAS ALONG AND SOUTH OF THE MOGOLLON RIM AT THESE
ELEVATIONS WILL LIKELY SEE A FOOT OR MORE OF POWDERY AND WIND DRIVEN
SNOWFALL.

HIGH PRESSURE WILL BUILD RAPIDLY IN THE WAKE OF THIS STORM AND
CONDITIONS BY NEXT WEEKEND WILL BE CLEAR AND MUCH WARMER. STAY TUNED
TO YOUR FAVORITE MEDIA OUTLET AND THE NATIONAL WEATHER SERVICE FOR
CONTINUING UPDATES ON THIS STORM.

&&

.AVIATION...FOR THE 12Z PACKAGE...EXPECT VFR CONDITIONS AND MAINLY
CLEAR SKIES OVER THE NEXT 24 HOURS. SOUTHWEST WINDS 10 TO 20 KTS BY
THIS AFTERNOON. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

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

&&

$$

PUBLIC.........PETERSON
AVIATION.......MAS

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF



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