Area Forecast Discussion
Issued by NWS Tucson, AZ

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000
FXUS65 KTWC 200405
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
905 PM MST SAT JUL 19 2014

.SYNOPSIS...EXPECT ISOLATED TO SCATTERED THUNDERSTORMS MOSTLY EAST
AND SOUTH OF TUCSON THROUGH THE MIDDLE OF THE UPCOMING WEEK. MUCH
HOTTER TEMPERATURES WILL OCCUR TUESDAY THROUGH THURSDAY...WITH NEAR
RECORD HIGHS POSSIBLE. A PRONOUNCED INCREASE IN THUNDERSTORM
ACTIVITY SHOULD THEN PREVAIL BY THE END OF THE UPCOMING WEEK.

&&

.DISCUSSION...IR SATELLITE IMAGERY AND SURFACE OBSERVATIONS
INDICATED MOSTLY CLEAR SKIES TO PARTLY CLOUDY SKIES ACROSS MUCH OF
SE AZ AT THIS TIME. SOMEWHAT THICKER CLOUDINESS WAS NOTED OVER FAR
ERN SECTIONS. DEWPOINTS AT LOWER ELEVATIONS VALID 20/04Z RANGED
FROM THE MID 40S-MID 50S F...AND THESE TEMPS WERE GENERALLY 2-6 DEGS
F HIGHER VERSUS 24 HOURS AGO. 20/00Z KTWC SOUNDING TOTAL PRECIP
WATER VALUE WAS ABOUT 1.10 INCHES...OR NEARLY 0.30 INCH LOWER VERSUS
FRI EVENING.

AXIS OF COLDER CLOUD TOPS WITH EMBEDDED SHOWERS/TSTMS EXTENDED FROM
FAR ERN SONORA/WRN CHIHUAHUA NWD INTO SWRN NEW MEXICO. CONVECTIVE
ACTIVITY SHOULD CONTINUE DURING THE NEXT SEVERAL HOURS JUST EAST TO
SOUTHEAST OF THIS FORECAST AREA UNDER DIFFLUENT FLOW ALOFT. CANNOT
COMPLETELY RULE OUT THE POSSIBILITY OF SHOWER/TSTM DEVELOPMENT
ASSOCIATED WITH OUTFLOW THAT MAY ENCROACH UPON FAR SERN SECTIONS
LATER TONIGHT.

HOWEVER...20/00Z NAM AND 20/01Z RUC HRRR DEPICT DRY CONDITIONS TO
OCCUR LATE TONIGHT...AND AM INCLINED TO BELIEVE THESE SOLUTIONS.
THUS...HAVE OPTED FOR DRY CONDITIONS AREA-WIDE THE REST OF TONIGHT.
EXPECT ISOLATED TO SCATTERED SHOWERS/TSTMS MOSTLY EAST AND SOUTH OF
TUCSON SUNDAY AFTERNOON AND SUNDAY EVENING. HIGH TEMPS SUN ARE
FORECAST TO BE QUITE SIMILAR TO TEMPS ACHIEVED THIS AFTERNOON.

PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL.

&&

.AVIATION...VALID THRU 21/06Z.
ISOLATED -TSRA/-SHRA NEAR THE FAR SERN AZ/SWRN NEW MEXICO BORDER
EAST OF KDUG ENDING AROUND 20/06Z. OTHERWISE...DRY CONDITIONS WILL
PREVAIL THE REST OF TONIGHT INTO EARLY SUNDAY MORNING. ISOLATED TO
SCATTERED -TSRA/-SHRA WILL THEN OCCUR MOSTLY EAST AND SOUTH OF KTUS
SUNDAY AFTERNOON AND SUNDAY EVENING. BRIEF MVFR VISIBILITIES AND
WIND GUSTS TO NEAR 35 KTS MAY OCCUR WITH THIS ACTIVITY. CLOUD DECKS
INTO SUNDAY EVENING WILL GENERALLY BE AT 8-12K FT AGL. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...ISOLATED TO SCATTERED THUNDERSTORMS WILL OCCUR
MOSTLY EAST AND SOUTH OF TUCSON THROUGH THE MIDDLE OF THE UPCOMING
WEEK. STRENGTHENING HIGH PRESSURE ALOFT WILL ALSO BRING HOTTER
TEMPERATURES TUESDAY THROUGH THURSDAY. THEREAFTER...INCREASED
THUNDERSTORM ACTIVITY SHOULD OCCUR DURING THE LATTER PART OF THE
UPCOMING WEEK AND INTO NEXT WEEKEND.

&&

.CLIMATE...NEAR RECORD HEAT EXPECTED TUESDAY THROUGH THURSDAY. THE
FORECAST EXCEEDS RECORD LEVELS ON WEDNESDAY AND THURSDAY WITH
TEMPERATURES AROUND 110 AT TUCSON INTERNATIONAL. THIS WOULD BE THE
FIRST 110 TEMPS OF THE YEAR AND HOTTEST JULY TEMPS SINCE 2011 (110
OR GREATER OCCURRENCES ARE MOST COMMON IN JUNE BEFORE THE MONSOON
ARRIVES).

&&

.PREV DISCUSSION...SUNDAY DOESN`T LOOK MUCH BETTER AND EVEN STARTS
TO PICK UP A BIT OF A SOUTHWESTERLY FLOW IN WESTERN AREAS AS THE
RIDGE STARTS TO BUILD IN ERNEST THROUGH WEST TEXAS AND SOUTHERN NEW
MEXICO. THE MONSOON WILL PROBABLY SPUTTER WITH BELOW AVERAGE DAYS
MUCH OF THE COMING WEEK.

STRONG RIDGE BUILDING THROUGH THE DESERT SOUTHWEST AND FRONT RANGE
THIS COMING WEEK. COMBINED WITH THE MARGINAL MOISTURE SITUATION
EXPECT NEAR RECORD HEAT TUESDAY AND ESPECIALLY WEDNESDAY AND
THURSDAY. THICKNESS REGRESSION ANALYSIS AND MODEL H8 TEMPS SCREAMING
FOR RECORD VALUES WEDNESDAY AND THURSDAY. THE EVENT IS AN OUTLIER SO
WE`RE BETTER SERVED WITH SOLID INDIVIDUAL MODEL ANALYSIS PERFORMANCE
OVER CONSENSUS SUITES. RAW DATA FROM BOTH GFS AND ECMWF SEEM TO BE
HANDLING THE MID WEEK HEAT PRETTY WELL...WITH MOS DATA A LITTLE LOW
DUE CLIMO INFLUENCE. WE WILL GO WITH TEMPERATURES NEAR 110 AT TIA
BOTH WEDNESDAY AND THURSDAY AS A BASELINE BUT POTENTIAL IS THERE FOR
A COUPLE OF DEGREES HOTTER. THE MAIN FACTOR TO INTERFERE WITH THE
RECORD HEAT FORECAST AT THIS POINT WOULD BE MOISTURE...AND AS OF NOW
IT ISN`T LOOKING TERRIBLY WET BY AT LEAST WEDNESDAY.

SURGE...PROBABLY A STRONG SURGE...WOULD BE A GOOD FIRST GUESS AFTER
A COUPLE OF DAYS OF RECORD HEAT AS LONG AS LARGER SCALE FEATURES
DON`T INTERFERE. WITH THE RIDGE AXIS ORIENTED EAST-WEST AND
POSITIONED NORTH OF OUR AREA WE SHOULD BE FINE FOR OUR PART OF THE
STATE. THE ECMWF EVEN SETS UP A STRONG MOISTURE FIELD THROUGH SONORA
AND INTO SOUTHEAST ARIZONA BY FRIDAY AND SATURDAY.

&&

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

&&

$$

VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON

FRANCIS
PREV DISCUSSION...MEYER




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