FXUS65 KFGZ 250929
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
230 AM MST FRI DEC 25 2009
.SYNOPSIS...A DRY AND COLD NORTHERLY FLOW WILL PERSIST INTO THE
WEEKEND. UNSETTLED WEATHER MAY RETURN EARLY NEXT WEEK AS A SERIES OF
PACIFIC WEATHER DISTURBANCES MOVE ACROSS THE SOUTHWEST UNITED STATES.
&&
DISCUSSION...HIGH PRESSURE IN THE MID- TO UPPER-LEVELS REMAINED
ALONG THE WEST COAST WHILE A STRONG LOW PRESSURE SYSTEM CONTINUED TO
SPIN OVER THE EASTERN TWO-THIRDS OF THE UNITED STATES. AS A
RESULT...A DEEP LAYER NORTH TO NORTHWEST FLOW WAS POSITIONED ACROSS
THE SOUTHWEST UNITED STATES. ASSOCIATED WITH THE LOW TO THE EAST AND
NORTHERLY FLOW A DEEP, COLD AIR MASS HAS PLUNGED SOUTHWARD FROM OVER
THE POLAR REGIONS. THE WESTERN EDGE OF THIS COLD POOL WILL CONTINUE
TO SPILL OVER THE ROCKY MOUNTAINS AND INTO ARIZONA INTO NEXT WEEK.
AS A RESULT...BELOW NORMAL TEMPERATURES LOOK TO CONTINUE. BY EARLY
NEXT WEEK...SEVERAL WEATHER DISTURBANCES WILL IMPACT THE SOUTHWEST. A
VERY WEAK SHORTWAVE WILL MOVE ACROSS ON SUNDAY WITH THE MAIN IMPACT
BEING AN INCREASE IN CLOUDS FROM SATURDAY INTO SUNDAY. A STRONGER
DISTURBANCE WILL MOVE ACROSS THE AREA ON MONDAY AND TUESDAY.
MODELS CONTINUE TO SHOW THE MAIN ENERGY WITH THE MONDAY/TUESDAY
SYSTEM HEADING WELL SOUTH OF ARIZONA WITH THE BEST CHANCE FOR
SHOWERS OVER THE EASTERN MOGOLLON RIM AND WHITE MOUNTAINS. ANOTHER
WEAK DISTURBANCE WILL MOVE ACROSS THE AREA FROM THE NORTHWEST AROUND
WEDNESDAY. NOT EXPECTING A SIGNIFICANT AMOUNT OF PRECIPITATION AT
THIS TIME HOWEVER, QUTIE A BIT OF UNCERTAINTLY REMAINS AND WILL NEED
TO MONITOR THE MONDAY THROUGH WEDNESDAY PERIOD CLOSELY .
TOWARD THE END OF NEXT WEEK...AT THIS TIME MODELS ARE INDICATING
THAT A SERIES OF WEAK AND MAINLY DRY WEATHER DISTURBANCES WILL BRUSH
NORTHERN ARIZONA. AS A RESULT...THE WEATHER LOOKS TO REMAIN MAINLY
DRY WITH TEMPERATURES MODERATING TO NEAR NORMAL LEVELS.
&&
.AVIATION...FOR THE 12Z PACKAGE...VFR CONDITIONS WITH OCCASIONAL
NORTH-NORTHEASTERLY BREEZES FOR THE 24 HR TAF PERIOD. AVIATION
DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC.........MCCOLLUM
AVIATION.......TC
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER INFORMATION.