Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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000
FXUS65 KFGZ 202215
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
315 PM MST SAT DEC 20 2014

.SYNOPSIS...
AREAS OF LOW CLOUDS AND FOG WILL FORM ONCE AGAIN OVER PORTIONS OF
NORTHEAST ARIZONA TONIGHT. OTHERWISE...DRY NORTHWEST FLOW ALOFT WILL
DELIVER FAIR WEATHER...A FEW CLOUDS AND GRADUALLY WARMING
TEMPERATURES THROUGH MONDAY. A DRY COLD FRONT WILL BRING COLDER
TEMPERATURES AND NORTHEASTERLY BREEZES FOR TUESDAY.

&&

.DISCUSSION...THE AREA OF LOW STRATUS AND FOG OVER NE ARIZONA HAS
ERODED QUICKLY THIS AFTERNOON...AND IS CURRENTLY LIMITED TO A FEW
AREAS BELOW 5500FT BETWEEN WINSLOW AND PAGE. OUR PRIMARY FORECAST
CHALLENGE WILL BE WITH REGARD TO THE FORMATION AND EXPANSION OF THE
INVERSION STRATUS AND FOG AGAIN TONIGHT AND EARLY TOMORROW.

SEVERAL FACTORS WILL BE IN PLACE WHICH MAY LIMIT THE AMOUNT OF LOW
CLOUDS AND FOG THAT FORMS OVERNIGHT...BUT IT LOOKS LIKE THE CLOUDS
WILL PREVAIL. A TIGHTENING GRADIENT ALOFT WILL PROMOTE STRONGER
NORTHWEST WINDS. BY DAYBREAK TOMORROW...FORECAST MODELS ARE
INDICATING 10-20KT WINDS JUST A COUPLE THOUSAND FEET OFF THE
SURFACE...WHICH MAY BE ENOUGH TO ERODE THE INVERSION AND SUBSEQUENT
CLOUDS BY MORNING...ESPECIALLY OVER NORTHEASTERN COCONINO COUNTY.
THIS FLOW WILL LIKELY ALSO PUSH THE CLOUDS FURTHER UP THE RIM TO THE
SOUTH OF WINSLOW...AND CREATE AN AREA OF UPSLOPE FOG. HIGH CLOUDS
OVERNIGHT MAY LIMIT THE RADIATIONAL COOLING AT THE SURFACE...BUT
WHERE THE STRATUS IS ALREADY IN PLACE...ITS NOT MUCH OF AN ISSUE.
OUR FORECAST THEREFORE WILL HAVE THE LOW CLOUDS AND FOG REFORMING
LATE THIS EVENING IN GENERALLY THE SAME AREAS AS IT WAS THIS
MORNING...THEN PUSHING FURTHER SOUTH TOWARD DAYBREAK. IN ANY
CASE...WE SHOULD SEE MOST OF THE LOW CLOUDS ACROSS NE ARIZONA
DISSIPATE TOMORROW AFTERNOON...WITH LESS REFORMING ON SUNDAY NIGHT.

OTHERWISE...A STRONG RIDGE OF HIGH PRESSURE BUILDING OVER THE WEST
COAST WILL KEEP NORTHERN ARIZONA UNDER NORTHWEST FLOW...WITH FAIR
AND MILD WEATHER THROUGH MONDAY. A RELATIVELY STRONG...BUT DRY COLD
FRONT WILL MOVE ACROSS THE NORTHLAND ON MONDAY NIGHT...BRINGING
COLDER TEMPERATURES AND BREEZY CONDITIONS. HIGHS ON TUESDAY WILL
COOL ABOUT 10 DEGREES 0N TUESDAY...WITH THE GREATEST IMPACT BEING
OVER THE NORTHEAST PART OF THE STATE. THE CHILL WILL BE SHORT-LIVED
HOWEVER...AS WARMER WESTERLY FLOW ALOFT QUICKLY BRINGS OUR
TEMPERATURES BACK TO NEAR NORMAL ON WEDNESDAY.

THE DETERMINISTIC MODELS AND ENSEMBLE MEMBERS ARE STARTING TO COME
INTO LINE WITH THE TROUGH TO IMPACT ARIZONA ON CHRISTMAS DAY.
CURRENT INDICATIONS ARE THAT THIS SYSTEM WILL HAVE VERY LIMITED
MOISTURE...AND WILL BRING STRONGER WINDS...COOLER TEMPERATURES...AND
ONLY A SLIGHT CHANCE FOR RAIN AND SNOW TO THE NORTHLAND.

&&

.AVIATION...FOR THE 00Z PACKAGE...LOW CLOUDS AND FOG REMAIN WITHIN
THE LITTLE COLORADO RIVER VALLEY GENERALLY TO THE NORTHWEST OF KINW.
THIS REGION OF LOW CLOUDS AND FOG ARE FORECAST TO EXPAND BEGINNING
IN THE EARLY EVENING. IFR TO VLIFR CONDITIONS WILL GENERALLY BE
LIMITED TO AREAS WITHIN THE LITTLE COLORADO RIVER VALLEY. IFR TO
VLIFR CONDITIONS ARE LIKELY OVERNIGHT AT KINW...WITH IFR CONDITIONS
POSSIBLE AT KPGA. VFR CONDITIONS ARE EXPECTED ELSEWHERE. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.


&&

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

&&

$$

PUBLIC.....BAK/JJ
AVIATION...RICKEY/BOHLIN

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF




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