000
FXUS65 KTWC 062115
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
215 PM MST FRI DEC 6 2013

.SYNOPSIS...ANOTHER COOL AND DRY DAY IS EXPECTED SATURDAY THEN A
STORM SYSTEM PASSING BY WELL TO THE NORTH LATE THIS WEEKEND WILL
BRING A CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW TO MAINLY NORTHERN
AREAS LATE SATURDAY INTO SUNDAY.  DRY CONDITIONS WILL THEN BE
IN STORE FOR THE COMING WEEK WITH MUCH BELOW NORMAL TEMPERATURES
MONDAY AND TUESDAY WARMING TO NEAR NORMAL BY THE END OF THE WEEK.

&&

.DISCUSSION...SUNNY AND RATHER COOL WITH TEMPERATURES STRUGGLING TO
CLIMB THANKS TO THE COLD AIR MASS SITTING OVER THE REGION.  MOST
AREAS WILL END UP 10-12 DEGREES COLDER THAN NORMAL TODAY.  THIS AIR
MASS WILL LOOSEN ITS GRIP A BIT SATURDAY AND THAT ALONG WITH A
SLIGHT INCREASE IN HIGH LEVEL MOISTURE WILL HELP TO HOLD UP SATURDAY
MORNING LOW TEMPERATURES A FEW DEGREES WARMER THAN THIS MORNING.
THEN HIGH TEMPERATURES DURING THE AFTERNOON SHOULD BE AROUND 5
DEGREES WARMER HOWEVER THERE WILL BE A BIT OF A SOUTHWEST BREEZE
WHICH WILL MAKE IT FEEL COOLER.

FOR LATE SATURDAY INTO SUNDAY...ANOTHER WAVE PASSING THROUGH THE
MEAN WESTERN US TROUGH WILL BRING A THREAT OF SHOWERS TO THE AREA
ALONG WITH SOMEWHAT REINFORCING THE COOL AIR MASS OVER THE REGION.
MODELS CONTINUE TO TREND TOWARD IT PASSING FURTHER NORTH MEANING THE
PRIMARY AREA OF PRECIPITATION SHIFTS FURTHER NORTH.  AT THIS POINT
LOOKS LIKE THE WHITES WILL SEE PRECIPITATION WHILE AREAS NEAR THE
MEXICO BORDER WILL LIKELY NOT SEE ANY.  THEREFORE HAVE ADJUSTED POPS
FOR SATURDAY NIGHT AND SUNDAY...HIGHER NORTH AND LOWER SOUTH.  THIS
EFFECTIVELY REMOVED THE CHANCE OF PRECIP OVER THE SOUTHERN THIRD OF
THE AREA SATURDAY NIGHT.  BEST SHOT OF SHOWERS THROUGHOUT WOULD BE
EARLY SUNDAY MORNING...THEN CLEARING OUT FROM THE WEST THROUGH THE
AFTERNOON AND EVENING.  OVERALL A COOL...PARTLY CLOUDY DAYS WITH A
BREEZE.

THEN THE MEAN LARGE SCALE TROUGH STARTS TO SHIFT EAST BUT BEFORE IT
DOES ONE FINAL WEAK WAVE WILL PASS ACROSS THE AREA.  THIS FEATURE
WILL BE DRY BUT WILL AGAIN SERVE TO MAINTAIN THE COOL CONDITIONS
MONDAY INTO TUESDAY MORNING WITH TEMPERATURES 10-15 DEGREES COLDER
THAN NORMAL.  DECENT POTENTIAL FOR WIDESPREAD BELOW FREEZING
TEMPERATURES MONDAY AND TUESDAY MORNINGS.

BEYOND THAT...MODELS INDICATE WEAK FLOW ALOFT WITH A VERY WEAK LOW
WELL TO OUR SW.  LATEST EC RUN IS A BIT MORE AGGRESSIVE WITH THIS
FEATURE EVEN INDICATING SOME LIGHT PRECIP OVER SE AZ ON WEDNESDAY.
AT THIS TIME HAVE DISCOUNTED THIS SOLUTION BUT WILL NEED TO BE
WATCHED.  OTHER THAN THAT A GENERAL WARMING TREND THROUGH THE WEEK
WITH TEMPERATURES NEARING NORMAL LEVELS BY THE END OF THE WEEK.
LONG RANGE MODELS CONTINUE TO HINT AT ANOTHER COLD UPPER LEVEL
SYSTEM AFFECTING OUR AREA NEXT WEEKEND BUT THAT IS BEYOND OUR
FORECAST PERIOD AT THIS TIME.  CERNIGLIA

&&

.AVIATION...VALID THU 07/00Z.  CLEAR SKIES ACROSS AZ TODAY WITH A
FEW WISPS OF CIRRUS LATER TONIGHT THEN A FEW CLOUDS ABV 15K FT
DEVELOPING AFT 07/21Z.  SURFACE WIND MOSTLY LESS THAN 10 KTS THRU
SATURDAY MORNING OR 07/18Z THEN BECOMING SW 8 TO 15 KT.  AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.  CERNIGLIA

&&

.FIRE WEATHER...MOSTLY CLEAR...COOL AND DRY THROUGH SATURDAY WITH
LIGHT WINDS THROUGH MIDDAY SATURDAY.  A WEATHER SYSTEM PASSING BY
WELL TO THE NORTH WILL BRING A CHANCE OF VALLEY RAIN AND MOUNTAIN
SNOW LATE SATURDAY INTO SUNDAY...MAINLY ACROSS NORTHERN AREAS.  AS
IT PASSES IT WILL ALSO KICK UP A BIT OF A SW BREEZE SATURDAY
AFTERNOON INTO SUNDAY.  BEYOND THAT DRY CONDITIONS ARE EXPECTED NEXT
WEEK WITH WELL BELOW NORMAL TEMPERATURES AT THE START OF THE WEEK
WHICH WILL GRADUALLY WARM UP TO NEAR NORMAL BY THE END OF THE WEEK.
CERNIGLIA

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

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