FXUS65 KFGZ 220411
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
910 PM MST MON DEC 21 2009
.SYNOPSIS...CLOUDY SKIES WILL CONTINUE TONIGHT. A PACIFIC STORM
SYSTEM WILL BRING SNOW AND LOWER ELEVATION RAIN WITH MUCH COLDER
TEMPERATURES TUESDAY AND WEDNESDAY. DRY WEATHER IS FORECAST FOR
THURSDAY THROUGH SATURDAY...WITH HIGH TEMPERATURES REMAINING BELOW
NORMAL.
&&
.DISCUSSION...A SIGNIFICANT WINTER STORM CONTINUES TO TAKE SHAPE
TONIGHT OVER THE WESTERN STATES. THE MAIN LOW IS NOW LOCATED ACROSS
THE PACIFIC NORTHWEST...DIVING SOUTH-SOUTHEASTWARD OVERNIGHT. AHEAD
OF THIS MAIN LOW...A STRONG JET STREAM IS MOVING INTO SOUTHERN
CALIFORNIA AND INTO ARIZONA. INCREASING MOISTURE...ESPECIALLY AT THE
MID LEVELS...ALONG WITH DIVERGENCE ALOFT DUE TO THE JET...SHOULD
LEAD TO SOME LIGHT PRECIPITATION LATE TONIGHT THROUGH EARLY TUESDAY
MORNING FROM FLAGSTAFF NORTHWARD. SNOW LEVELS ARE EXPECTED TO BE
NEAR 5500 FEET...WITH AROUND AN INCH POSSIBLE BY MORNING. FORECASTS
HAVE BEEN UPDATED TO INCLUDE THIS SCENARIO.
LATEST FORECAST GUIDANCE REMAINS IN GOOD AGREEMENT IN BRINGING THE
LOW OVER THE PACIFIC NORTHWEST RAPIDLY SOUTHWARD...CENTERED NEAR LAS
VEGAS BY LATE TUESDAY AFTERNOON...THEN NEAR THE WHITE MTNS BY
WEDNESDAY MORNING. THIS WILL CREATE A PERIOD OF STRONG UPWARD MOTION
OVER MOST OF OUR FORECAST AREA...WITH SNOW DEVELOPING ABOVE
5500-6000 FEET...SPREADING EASTWARD THROUGH THE DAY. MODERATE TO
HEAVY SNOW AMOUNTS ARE LIKELY ALONG WITH GUSTY WINDS...MAKING FOR
POOR TRAVEL CONDITIONS. SOME WRAP AROUND SNOW IS INDICATED NORTH OF
THE LOW TRACK...ACROSS NORTHEAST AND NORTH CENTRAL ARIZONA TUESDAY
NIGHT INTO WEDNESDAY MORNING.
A WINTER WX ADVISORY IS IN EFFECT FOR PORTIONS OF THE NORTHLAND
TUESDAY AND WEDNESDAY. SEE PHXWSWFGZ FOR DETAILS. THE CURRENT
ADVISORY IS FOR ELEVATIONS ABOVE 6500 FEET. THOUGH SNOW WILL OCCUR
BELOW THIS LEVEL...EVENTUALLY BELOW 5000 FEET...THE CURRENT THINKING
IS THAT THE BULK OF PRECIP ACCUMULATION WILL HAVE ENDED BEFORE SNOW
LEVEL REALLY CRASH WEDNESDAY MORNING. CURRENT FORECASTS ARE IN GOOD
SHAPE...THOUGH SOME ADJUSTMENTS WILL BE MADE TO INCLUDE AN INCH OR
TWO OF SNOW DOWN INTO THE LOWER PORTIONS OF THE LITTLE COLORADO RIVER
VALLEY...AND EVEN THE PAGE AREA TUESDAY AFTERNOON AND EVENING.
ON WEDNESDAY...THE UPPER LOW IS MOVING EASTWARD THROUGH THE DAY.
THERE IS A WRAP AROUND MOISTURE SIGNAL WEDNESDAY AFTERNOON OVER
AREAS ALONG AND NORTH OF THE MOGOLLON RIM...AND WILL KEEP A SLIGHT
CHANCE OF PRECIP GOING FOR AREAS EAST OF A LINE FROM PAGE TO PAYSON.
WEST OF THIS LINE CLEARING CONDITIONS ARE EXPECTED.
THURSDAY THROUGH SATURDAY...DRY WX WILL RETURN BUT TEMPS WILL REMAIN
BELOW NORMAL. SUNDAY AND MONDAY...ANOTHER PACIFIC STORM IS SHOWN TO
MOVE INTO THE DESERT SOUTHWEST BRINGING ANOTHER CHANCE OF RAIN AND
SNOW.
&&
.AVIATION...FOR THE 06Z PACKAGE...FOR THE 06Z PACKAGE...EXPECT
GRADUALLY LOWERING CIGS FROM KFLG WEST AND NORTH THROUGH 12Z-15Z.
SCT -SHSN WILL DEVELOP AFT 08Z-10Z...MAINLY NORTH OF KFLG. MVFR
CONDITIONS WILL EXIST MOST AREAS NORTH OF KFLG BY 12Z-14Z.
CONDITIONS WILL CONTINUE TO DETERIORATE THROUGH TUESDAY AMD TUESDAY
NIGHT FROM NORTHWEST TO SOUTHEAST. WDSPRD MVFR CONDITIONS WILL EXIST
BY 16Z-18Z...WITH SCT IFR CONDITIONS IN SNOW ABV 6000 FEET BY
19Z-21Z. CONDITIONS WILL NOT IMPROVE THROUGH 06Z WEDNESDAY. AVIATION
DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 9 AM TUESDAY TO 9 AM MST WEDNESDAY
FOR AZZ004-006-015-016.
WINTER WEATHER ADVISORY FROM NOON TUESDAY TO NOON MST WEDNESDAY
FOR AZZ011-039.
WINTER WEATHER ADVISORY FROM 3 PM TUESDAY TO 3 PM MST WEDNESDAY
FOR AZZ017.
&&
$$
PUBLIC.........JJ / DL
AVIATION.......PETERSON
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER
INFORMATION.
