000
FXUS65 KTWC 181635
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ 
930 AM MST TUE NOV 18 2008

.SYNOPSIS...
STRONG HIGH PRESSURE ALOFT WILL BRING MOSTLY CLEAR SKIES 
WITH WARM DAYTIME TEMPERATURES THROUGH WEDNESDAY. THE HIGH PRESSURE 
SYSTEM IS EXPECTED TO WEAKEN DURING THE LATTER PART OF THE WEEK AND 
INTO NEXT WEEKEND. THIS WILL LEAD TO SOME INCREASE IN CLOUDINESS AND 
A VERY GRADUAL COOLING TREND.

&&

.DISCUSSION...STRONG UPPER HIGH IS OVER THE SOUTHWEST UNITED STATES. 
DEEP TROUGH IS DIGGING SOUTH OVER THE EAST COAST. THIS PATTERN 
WILL PROMOTE CONTINUED RIDGING OVER ARIZONA THROUGHOUT THE WEEK. AS 
A RESULT DRY CONDITIONS AND ABOVE NORMAL TEMPERATURES WILL PREVAIL 
OVER THE AREA. 12Z TUS SOUNDING SHOWS WARMING BELOW 5000 FEET. 
TEMPERATURES WERE WARMER YESTERDAY THAN FORECAST GUIDANCE 
INDICATED...WITH MANY LOCATIONS WITHIN A DEGREE OR TWO OF RECORD 
VALUES. THIS WAS A RESULT OF STRONG UPPER RIDGING AND OPTIMAL 
DOWNSLOPE WIND COMPONENT. HIGHS TODAY WILL BE NEAR RECORD VALUES AT 
MANY LOCATIONS. ANOTHER WARM DAY ON WEDNESDAY...IN FACT WILL NEED TO 
BUMP CURRENT FORECAST TEMPS UP A COUPLE OF DEGREES. A FEW SPOTS WILL 
AGAIN APPROACH RECORD VALUES ON WEDNESDAY...BUT RECORD HIGHS ARE A 
BIT WARMER WEDNESDAY...SO PROBABLY WILL HAVE A LESSER CHANCE OF 
HITTING VERSUS TODAY.

STRONG SURFACE HIGH IS LOCATED OVER TEXAS...AS WEAK SURFACE TROUGH 
IS POSITIONED OVER THE GULF OF CALIFORNIA. THIS HAS CREATED A FAIRLY 
TIGHT SURFACE GRADIENT OVER SOUTHEAST ARIZONA THIS MORNING...AS A 
RESULT BREEZY EASTERLY WINDS ARE OCCURRING OVER MANY LOCATIONS. 
SPEEDS WILL BE IN THE 10-20 MPH RANGE AND GUSTY IN TERRAIN FAVORED 
AREAS AND LIGHTER ELSEWHERE.

UPPER HIGH WILL GRADUALLY FLATTEN THROUGHOUT THE FORECAST PERIOD. 
THIS WILL CONTINUE THE DRY AND WARM CONDITIONS...WITH A SLIGHT 
COOLING TREND TOWARDS THE END OF THE WEEK. FARTHER OUT IN THE 
EXTENDED MODELS CONTINUE TO HAVE A DIFFICULT TIME RESOLVING THE 
EVOLUTION OF NORTHERN PACIFIC SYSTEMS AND THEIR TRANSITION INTO THE 
WEST COAST...SO WILL LEAVE LOW END NON-WEATHER ASSOCIATED POPS 
INTRODUCED BY THE MID SHIFT.

&&

.FIRE WEATHER...A TIGHT SURFACE PRESSURE GRADIENT WILL PRODUCE GUSTY 
WINDS FROM THE EAST AND SOUTHEAST TODAY. RED FLAG CRITERIA MAY BE 
APPROACHED FROM TIME-TO-TIME THIS MORNING AND INTO EARLY THIS 
AFTERNOON. HOWEVER CONDITIONS ARE NOT LIKELY TO BE WIDESPREAD ENOUGH 
FOR RED FLAG WARNING ISSUANCE.

&&

.AVIATION...THE SKY WILL REMAIN CLEAR MOST AREAS THROUGH TONIGHT. 
HOWEVER A VERY WEAK UPPER LOW OFF NORTHERN BAJA CALIFORNIA WILL 
SPREAD SOME CIRRUS CLOUDS OVER FAR SOUTHEAST ARIZONA TODAY AND 
TONIGHT. SURFACE WINDS TODAY WILL GENERALLY BE OUT OF THE EAST AT 10 
TO 20 KTS WITH OCCASIONAL GUSTS TO 30 KTS. AVIATION DISCUSSION NOT 
AMENDED FOR TAF AMENDMENTS.

&&

.CLIMATE...
RECORD OR NEAR RECORD HIGH TEMPERATURES FOR NOVEMBER 18TH...

                    FORECAST   RECORD/
                      HIGH      YEAR
TUCSON INTL APT        85      86/1990
AJO                    87      87/1943
ORGAN PIPE CACTUS      88      90/2007
ORACLE                 73      77/1975
PICACHO PEAK           87      86/1999
NOGALES 6N             82      84/2006
BISBEE-DOUGLAS APT     79      81/2007
SIERRA VISTA           76      79/2006

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

$$

WEATHER.GOV/TUCSON