403
FXUS65 KFGZ 222222
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
322 PM MST FRI FEB 22 2019
SYNOPSIS
A MAJOR WINTER STORM WILL BRING WIDESPREAD MODERATE TO
HEAVY SNOWFALL AND DANGEROUS TRAVEL CONDITIONS TO MUCH OF THE
REGION THROUGH THIS AFTERNOON BUT COME TO AN END OVERNIGHT. LOOK
FOR FAIR BUT COLD WEATHER OVER THE WEEKEND. FROM MONDAY ONWARD A
WARMER WEATHER PATTERN WILL DELIVER NEAR NORMAL DAYTIME
TEMPERATURES BY THE MIDDLE OF NEXT WEEK.
DISCUSSION
SHOWERS CONTINUE TO MOVE ACROSS NORTHERN ARIZONA AS THE MAIN
MOISTURE TAP MOVES EASTWARD. HAVE BEGUN TO EXPIRE THE WINTER STORM
WARNINGS FOR THE WESTERN PARTS OF THE AREA INCLUDING YAVAPAI AND
WESTERN COCONINO COUNTY. SOME SNOW SHOWERS WILL BE POSSIBLE IN
LOCATIONS THROUGH THE EVENING HOURS AS A VERY UNSTABLE AIRMASS
MOVES IN BEHIND THE MOISTURE PLUME, BUT STILL AHEAD OF THE TROUGH
AXIS.
AS THIS SYSTEM EXITS TO THE EAST, CLEARING IS EXPECTED OVERNIGHT.
THIS WILL LEAD TO EXTREMELY COLD TEMPERATURES IN AREAS THAT SAW
SIGNIFICANT SNOWFALL OVER THE LAST FEW DAY. SINCE THE SNOW HELPS
RADIATE LONGWAVE ENERGY OUT AT THE SURFACE, WHILE ALSO WORKING AS
A STRONG INSULATOR LIMITING THE AVAILABLE HEAT FROM THE GROUND
UNDERNEATH.
THESE COOLER TEMPERATURES WILL ALLOW FOR AN INVERSION TO SET UP
OVER THE HIGH ALTITUDE BASINS OF NORTHEASTERN ARIZONA, INCLUDING
THE LITTLE COLORADO RIVER BASIN, AND CHINLE VALLEY. CURRENT MODELS
ARE NOT HANDLING THIS MESO-SCALE EVENT WELL, AND HAVE GENERALLY
LIMITED MAXIMUM TEMPERATURE RISES IN THE AREA THROUGH AT LEAST
TUESDAY. WHILE CONFIDENCE IN AN INVERSION ACROSS THESE HIGH
ALTITUDE BASINS IS HIGH, CONFIDENCE IN LOCATION OF AND TIMING OF
INVERSION BREAK UP IS LOW AT THE MOMENT.
ELSEWHERE EXPECT A GENERAL WARMING TREND TO BEGIN NEXT WEEK AFTER
A COLD WEEKEND. TEMPERATURES WILL RETURN TO NEAR NORMAL THROUGH
THE WEEK. WITH ZONAL FLOW AND A WEAK RIDGE BUILDING INTO THE
REGION THROUGH THE WORK WEEK. .
AVIATION...FOR THE 00Z PACKAGE
POOR AVIATION CONDITIONS WITH
MVFR/IFR/LIFR CONDITIONS TO DECREASE FROM WEST TO EAST TONIGHT AS
THE STORM SYSTEM MOVES AWAY. PATCHY FOR MAY DEVELOP TONIGHT. VFR
WITH A STABILIZING AIRMASS OVERHEAD AFT 15Z SAT. AVIATION DISCUSSION
NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
THE STRONG WINTER SYSTEM WILL MOVE EASTWARD OUT OF
NORTHERN ARIZONA TONIGHT. EXPECT CLEARING CONDITIONS FROM WEST TO
EAST. FOR THE WEEKEND, COLD AND DRY WEATHER IS EXPECTED, WITH POOR
TO MARGINAL AFTERNOON VENTILATION RATES DUE TO A STABILIZING AIRMASS.
MONDAY THROUGH WEDNESDAY...DRY CONDITIONS ARE FORECAST. TEMPERATURES
WILL REMAIN COLD, BUT GRADUALLY WARM THROUGH THE PERIOD.
FGZ WATCHES/WARNINGS/ADVISORIES
WINTER STORM WARNING UNTIL 5 PM MST THIS AFTERNOON FOR AZZ005-
009>016-018-038>040.
WINTER STORM WARNING UNTIL 8 PM MST THIS EVENING FOR AZZ017.
PUBLIC...SUK
AVIATION...DL
FIRE WEATHER...DL
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF
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