000
FXUS65 KTWC 202120
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
220 PM MST MON MAY 20 2013

.SYNOPSIS...A WEAK UPPER LEVEL RIDGE WILL MOVE ACROSS THE STATE
TUESDAY ANOTHER QUIET WEATHER DAY TUESDAY.  A DEEP UPPER LEVEL LOW
MOVING INTO THE PACIFIC NORTHWEST TUESDAY WILL DEEPEN ALONG THE
ENTIRE WEST COAST AND LINGER OVER THE REGION WELL INTO NEXT WEEK.
THIS WILL RESULT IN A PROLONGED PERIOD OF DRY SOUTHWEST FLOW ACROSS
SOUTHERN ARIZONA WITH ABOVE NORMAL AFTERNOON TEMPERATURES AND A FEW
GUSTY AFTERNOONS.

&&

.DISCUSSION...THE BROAD UPPER LEVEL TROUGH THAT HAS MAINTAINED THE
DRY NW FLOW ACROSS THE AREA WHICH HAS HELD TEMPERATURES NEAR NORMAL
LEVELS IS MOVING OUT INTO THE CENTRAL PLAINS AND WILL NO LONGER BE A
DIRECT PLAYER IN OUR WEATHER.  A SHORT WAVE RIDGE WILL PASS ACROSS
THE AREA TUESDAY HAVING A LIMITED AFFECT ON THE SENSIBLE WEATHER
OTHER THAN ALLOWING TEMPERATURES TO BE A DEGREE OR TWO WARMER AND
SLIGHTLY LESS WIND THAN THIS AFTERNOON.  BUT THE PASSING OF ITS AXIS
WILL OPEN THE DOOR TO THE INFLUENCE OF THE DEEP LATE SEASON UPPER
LOW/TROUGH THAT WILL SETTLE IN ALONG THE WEST COAST AND REMAIN IN
THAT GENERALLY AREA IN ONE FORM OR ANOTHER WELL INTO NEXT WEEK.

THE FIRST HINT OF THAT TROUGH INFLUENCE WILL BE THE HIGH CLOUDS THAT
WILL SPREAD ACROSS THE AREA LATER TUESDAY INTO TUESDAY NIGHT.  THEY
WILL CLEAR OUT DURING THE DAY WEDNESDAY BUT FROM THE LOOK OF THINGS
BANDS OF HIGH LEVEL MOISTURE WILL STREAM ACROSS ARIZONA FROM TIME TO
TIME FROM WEDNESDAY NIGHT INTO NEXT WEEK.  DUE TO THE POSITION OF
THE LOW AND FLOW DIRECTION I AM NOT SEEING ANY POTENTIAL FOR
PRECIPITATION OVER OUR NECK OF THE WOODS.  THE GREATEST IMPACT FOR
OUR AREA FROM THIS SETUP WILL BE THE OCCASIONAL BREEZY/WINDY PERIODS
THAT WE WILL GET ESPECIALLY AS FEATURES ROTATE AROUND THE BASE OF
THE TROUGH.  THE BASIC IDEA IS DRY...SOMEWHAT WARMER THAN NORMAL
WITH GUSTY AFTERNOON WINDS NOW AND THEN THURSDAY INTO EARLY NEXT
WEEK WHICH IS MORE OF A FIRE WEATHER CONCERN THAN A CONCERN FOR THE
GENERAL PUBLIC.  CERNIGLIA

&&

.AVIATION...SKC THRU TONIGHT OR 21/12Z...WITH A THICKENING HIGH
CLOUD TREND TUESDAY. SURFACE WIND THROUGH 21/03Z WLY/NWLY 10-20 KTS
WITH GUSTS 20-30 KTS...THEN SURFACE WIND LESS THAN 10 KTS OVERNIGHT
WITH TUESDAY AFTN WINDS LIGHTER THAN TODAY...MAINLY IN THE 10-15 KT
RANGE. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...NW WINDS WILL DECREASE THROUGH THIS EVENING ALTHOUGH
SOME SPOTS WILL REACH CRITICAL FIRE WEATHER CRITERIA FOR A FEW
HOURS...ESPECIALLY IN THE UPPER GILA RIVER VALLEY.  WILL ISSUE A RED
FLAG WARNING INTO EARLY EVENING.

LIGHTER...MEANING MORE NORMAL DIURNAL WINDS...AND WARMER
TEMPERATURES ARE FORECAST TUESDAY UNDER HIGH PRESSURE.  AS A LARGE
AREA OF LOW PRESSURE SETS UP ALONG THE WEST COAST...SOMEWHAT
STRONGER SOUTHWEST WINDS ARE FORECAST TO BEGIN WEDNESDAY THROUGH THE
HOLIDAY WEEKEND YIELDING OCCASIONAL CRITICAL FIRE WEATHER CONDITIONS
ACROSS SE AZ AS DRY WEATHER PERSISTS...KD

&&

.CLIMATE...TUCSON WILL MAKE ANOTHER RUN TOWARD THE FIRST 100 DEGREE
DAY OF 2013 ON WEDNESDAY.  MOST OF THE TEMPERATURE GUIDANCE THAT WE
ACCESS TO...FROM MOS GUIDANCE TO BIAS-CORRECTED GUIDANCE TO GFS
ENSEMBLES GUIDANCE...ARE NOT FORECASTING 100 FOR TUCSON THIS WEEK.
HOWEVER THE EC AND UKMET 850-700 MB THICKNESS VALUES ON WEDNESDAY
ARE CONTINUING TO SHOW EITHER 99 OR 100 FOR TUCSON.  SO THERE IS A
SLIGHT CHANCE THAT TUCSON WILL HIT 100 THIS WEEK.  AT THIS POINT I
WILL CONTINUE TO KEEP FORECAST HIGH ON WEDNESDAY AT 98.  IF THE
FIRST 100 DOESN`T OCCUR ON WEDNESDAY...WE WILL LIKELY HAVE TO WAIT
UNTIL NEXT MONDAY FOR OUR NEXT SHOT.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...RED FLAG WARNING FOR SOUTHERN
PART OF FIRE WEATHER ZONE 146 AND NE PART OF ZONE 148 UNTIL 8 PM
THIS EVENING.

&&

$$

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