Weather Service Report


951 
FXUS65 KFGZ 191656
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
950 AM MST SUN APR 19 2015

.SYNOPSIS...WEAK FLOW ALOFT WILL KEEP ARIZONA IN A MILD WEATHER 
PATTERN WITH SLIGHT CHANCES FOR HIGH BASED SHOWERS IN THE MOUNTAIN 
AREAS EACH AFTERNOON THROUGH MONDAY. ON TUESDAY COLDER AIR WILL MOVE 
DOWN THE WEST COAST CAUSING A COLD LOW TO SET UP OVER SOUTHERN 
CALIFORNIA. ON THURSDAY AND FRIDAY OUR LONG RANGE MODEL GUIDANCE 
SHOWS THIS LOW WEAKENING AS IT MOVES SLOWLY EASTWARD INTO ARIZONA. 
EXPECT FAIR CHANCES FOR SHOWERS ON THURSDAY AND FRIDAY AS THE LOW 
MOVES THROUGH THE REGION.

&&

.DISCUSSION...MOSTLY FAIR WEATHER CONDITIONS ARE FORECAST FOR THE 
NEXT FEW DAYS WITH SLIGHT CHANCES FOR A FEW HIGH BASED SHOWERS AND A 
THUNDERSTORM OR TWO OVER THE MOUNTAIN REGIONS OF NORTHERN ARIZONA. 
COLDER UNSTABLE AIR WITH SHOWERS WILL MOVE INTO ARIZONA ON THURSDAY 
AND FRIDAY WITH A SLOW MOVING CUT OFF LOW. SHOWERS MAY LINGER INTO 
SATURDAY WITH WARMER TEMPERATURES RETURNING AS COLDER TEMPERATURES 
AROUND THE CUT OFF LOW MOVES EAST OF THE STATE. 

MORNING FORECAST GRIDS LOOK GOOD NO UPDATES.

&&

.PREVIOUS DISCUSSION...A BIT OF ADDITIONAL MID LEVEL MOISTURE WILL 
MOVE ACROSS NORTHERN ARIZONA TODAY AND MONDAY MOVING IN FROM THE 
WEST NORTHWEST. THE MAIN IMPACT WILL BE MORE EXTENSIVE AFTERNOON 
CLOUD DEVELOPMENT OVER THE MOUNTAINS. VERTICAL DEVELOPMENT OF CLOUDS 
WILL BE VIGOROUS ENOUGH TO PRODUCE SOME SHOWERS BUT THE SUB-CLOUD 
LAYER IS SO DRY ONLY LOOKING AT A SLIGHT CHANCE OF SPRINKLES OR A 
FEW HUNDREDTHS OF AN INCH OF PRECIPITATION MAKING IT TO THE GROUND. 
A STRAY THUNDERSTORM IS POSSIBLE BUT IN GENERAL BASES OF SHOWERS 
WILL BE TOO HIGH/COLD FOR GOOD LIGHTNING POTENTIAL. A WARMER AIR 
MASS HAS MOVED IN SO LOOK FOR SEASONABLE TEMPERATURES THE NEXT TWO 
DAYS.

FOR TUESDAY AND WEDNESDAY...HIGH PRESSURE AND A DRIER SOUTHWEST FLOW 
WILL BE THE DOMINATE WEATHER FEATURE. LOOK FOR GENERALLY DRY 
CONDITIONS, A FEW CLOUDS AND SEASONABLE TEMPERATURES. HOWEVER, WINDS 
WILL BE ON THE INCREASE ON WEDNESDAY AS A LOW PRESSURE SYSTEM 
APPROACHES. 

THURSDAY INTO SATURDAY...LONGER TERM MODELS INDICATE NORTHERN 
ARIZONA WILL SEE COOLER TEMPERATURES AND UNSETTLED WEATHER WITH THE 
PASSAGE OF A PACIFIC LOW AND SURFACE COLD FRONT. 

&&

AVIATION...FOR THE 18Z PACKAGE...VFR CONDITIONS ARE EXPECTED TO 
PERSIST THROUGH 18Z MONDAY. A FEW HIGH BASED SHOWERS OR TSTORMS ARE 
EXPECTED AFTER 20-21Z...MOST NUMEROUS FROM THE GRAND CANYON 
SOUTHWARD. GUSTY OUTFLOW WINDS UP TO 30-35 KTS ARE POSSIBLE NEAR 
SHOWERS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...LINGERING MOISTURE AND AFTERNOON INSTABILITY WILL 
KEEP THE CHANCE FOR AN ISOLATED HIGH BASED SHOWER OR THUNDERSTORM IN 
THE FORECAST OVER THE MOUNTAINOUS AREAS OF NORTHERN ARIZONA THROUGH 
MONDAY. OTHERWISE...EXPECT ABOVE NORMAL TEMPERATURES WITH LIGHT TO 
BREEZY WINDS.

TUESDAY THROUGH THURSDAY...MAINLY DRY CONDITIONS ARE EXPECTED 
THROUGH WEDNESDAY. ANOTHER PACIFIC LOW MOVES INTO ARIZONA FROM THE 
WEST WITH A TREND TOWARDS COOL AND UNSETTLED WEATHER BY THURSDAY.


&&

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

&&

$$

PUBLIC.........BOHLIN/MCCOLLUM 
AVIATION.......MCS 
FIRE WEATHER...MCS

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT 
WEATHER.GOV/FLAGSTAFF





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