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  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab AZ Page Main Text Page