Expires:No;;396526
FPUS55 KFGZ 040339
ZFPFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
840 PM MST SAT APR 3 2010
.SYNOPSIS...DRY WEATHER IS EXPECTED THROUGH SUNDAY. GUSTY SOUTHWEST 
WINDS ARE FORECAST TO REDEVELOP AND BECOME DURING THE DAY SUNDAY IN 
ADVANCE OF A PACIFIC LOW. ON MONDAY...THE PACIFIC LOW AND ASSOCIATED 
COLD FRONT WILL DELIVER COOLER TEMPERATURES AND A SLIGHT CHANCE OF 
SHOWERS TO NORTHERN ARIZONA...ALONG WITH EVEN STRONGER DAYTIME 
WINDS. HIGH PRESSURE WILL SPELL A RETURN TO WARMER TEMPERATURES AND 
DRY CONDITIONS BY MIDWEEK.
&&
.DISCUSSION...COMPARING SOME OF THE OBSERVATIONS TO THE GFS...THE 
MODEL IS A LITTLE WEAKER WITH THE SOUTHERN SHORTWAVE MOVING THROUGH 
CENTRAL CALIFORNIA AND NEVADA. MID-LEVEL DECK HAS DEVELOPED FROM 
WILLIAM AZ NORTH UP INTO NORTHWEST ARIZONA...INCLUDING THE KAIBAB 
PLATEAU. WILL UPDATE CLOUD COVER FOR THE OVERNIGHT PORTION OF THE 
FORECAST. THE FORECAST FROM THE MODEL AND THE GUIDANCE MAY SHOW 
STRONGER WINDS FOR SUNDAY...WILL BE INTERESTING TO WATCH FOR THIS AS 
THE 00Z RUN COMES IN. 
&&
.PREVIOUS DISCUSSION /230 PM MST/...ZONAL WESTERLY FLOW WAS LOCATED 
ACROSS ARIZONA DURING THE AFTERNOON HOURS. OVER THE NEXT 24 TO 
36-HOURS A PACIFIC STORM SYSTEM WILL MOVE ON TO THE WEST COAST OF 
THE UNITED STATES. DURING THIS PERIOD DRY CONDITIONS WILL CONTINUE 
ACROSS ARIZONA WITH FURTHER WARMING OF DAYTIME TEMPERATURES ON 
SUNDAY. HOWEVER...PRESSURE GRADIENTS WILL STRENGTHEN ALOFT IN 
RESPONSE TO THE APPROACHING LOW. IT IS SPRING AND WITH DAYTIME 
HEATING AND HIGHER SUN ANGLE...WINDS ALOFT WILL EASILY MIX TO THE 
SURFACE. FOR TONIGHT GUSTY WINDS WILL RAPIDLY DIMINISH AFTER SUNSET. 
FOR SUNDAY...WITH DAYTIME HEATING/MIXING...SOUTHWEST WINDS OF 20 TO 
35 MPH WITH GUSTS TO 45 MPH WILL DEVELOP BY THE AFTERNOON. 
ON MONDAY...THE WEST COAST STORM WILL HEAD ACROSS THE GREAT BASIN 
AND INTERMOUNTAIN WEST. EVEN THOUGH THIS IS A FAIRLY STRONG SYSTEM 
IT WILL ESSENTIALLY BRUSH ARIZONA BRINGING JUST A SLIGHT CHANCE OF 
SHOWERS TO AREAS FROM THE MOGOLLON RIM NORTHWARD. THE MAIN IMPACT 
WILL BE A ROUND OF WEST TO SOUTHWEST WINDS OF 20 TO 35 MPH WITH 
GUSTS TO NEAR 50 MPH...MAINLY FROM THE MOGOLLON RIM NORTHWARD. 
TEMPERATURES WILL COOL AS A COLD FRONT SWEEPS ACROSS THE AREA DURING 
THE DAY. 
FROM TUESDAY INTO FRIDAY...ON TUESDAY A WEAK DISTURBANCE FROM THE 
NORTH COULD BRING ANOTHER ROUND OF GUSTY WINDS...EVEN COOLER 
TEMPERATURES AND A CONTINUED SLIGHT CHANCE OF SHOWERS. BEYOND 
TUESDAY...HIGH PRESSURE IS EXPECTED TO USHER IN DRY CONDITIONS... 
WARMER TEMPERATURES AND A RETURN TO MORE TYPICAL 10 TO 20 MPH 
SOUTHWESTERLY AFTERNOON BREEZES.
 
&&
.AVIATION...FOR THE 06Z PACKAGE...VFR CONDITIONS ARE EXPECTED FOR 
THE NEXT 24 HOURS WITH VARIABLE HIGH CLOUDS. SW20-30KT WINDS GUSTING 
35-45KT ARE EXPECTED TO DEVELOP 16Z-18Z SUNDAY THEN DIMINISH TO 10 
TO 15 KTS AFT 02-03Z MONDAY. AVIATION DISCUSSION NOT UPDATED FOR 
AMENDMENTS.
&&
.FIRE WEATHER...HIGH PRESSURE WILL BUILD ACROSS THE REGION WITH 
WARMER DAYTIME TEMPS THROUGH SUNDAY. THE MINIMUM RELATIVE HUMIDITY 
WILL BE 15 TO 20 PERCENT. WINDS WILL BECOME WINDY ON SUNDAY AS 
ANOTHER PACIFIC LOW PRESSURE SYSTEM AND COLD FRONT APPROACHES THE 
AREA. A COLD FRONT WILL MOVE ACROSS THE AREA MONDAY AND MONDAY NIGHT 
WITH STRONGER WINDS...INCREASING RH...AND A SLIGHT CHANCE OF RAIN 
AND SNOW SHOWERS.
TUESDAY THROUGH THURSDAY...NORTH WINDS ON TUESDAY WILL BRING DRY AND 
COOL CONDITIONS. WEDNESDAY AND THURSDAY WILL BE WARMER EACH DAY WITH 
MINIMUM RH OF 8 TO 13 PERCENT.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE
&&
$$
PUBLIC....................TC/MCCOLLUM
AVIATION/FIRE WEATHER.....TC
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER INFORMATION.