Area Forecast Discussion
Issued by NWS Tucson, AZ

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000
FXUS65 KTWC 240356
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
900 PM MST WED JUL 23 2014

.SYNOPSIS...ENOUGH MOISTURE IS BACK IN PLACE FOR A FEW SHOWERS AND
THUNDERSTORMS. HOTTER TEMPERATURES ARE POSSIBLE AGAIN THURSDAY.
THUNDERSTORMS ARE EXPECTED TO INCREASE FRIDAY INTO THE
WEEKEND...ESPECIALLY SATURDAY AFTERNOON AND SATURDAY NIGHT.

&&

.DISCUSSION...STILL A FEW SHOWERS WITH EMBEDDED THUNDERSTORMS AROUND
FIRING ON OUTFLOWS FROM EARLIER ACTIVITY. A GREAT POTENTIAL
CONVECTION DAY WASTED WITH LESS THAN FAVORABLE MID LEVEL TEMPERATURE
PROFILE. TRENDS POINT TOWARD LESS ON THURSDAY WITH MOISTURE AGAIN
TEMPORARILY A CONCERN AS UPSTREAM AREAS IN SOUTHERN NEW MEXICO DRY
OUT A LITTLE. 00Z KTWC SOUNDING CAME IN WITH A HEALTHY 1.6 INCHES
BUT LATEST BLENDED SATELLITE PRECIPITABLE WATER ESTIMATES JUST UNDER
AN INCH IN SOUTH CENTRAL NEW MEXICO AS LOWER LEVELS SHOW SOME DRYING
TRENDS.

UPWARD TREND STARTS AGAIN ON FRIDAY AS WE ADD A SOUTHERLY COMPONENT
TO THE FLOW...AND EVEN MORE ON SATURDAY WITH INVERTED TROUGH
INFLUENCE WRAPPING AROUND THE HIGH.

&&

.AVIATION...VALID THRU 25/03Z.
ISOLATED -SHRA/-TSRA THIS EVENING...WITH CLEARING TRENDS IN THE
EARLY MORNING HOURS. LESS CONVECTION AND CLOUD COVER IN GENERAL
EXPECTED THURSDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.

&&

.FIRE WEATHER...MOISTURE HAS RETURNED TO SOUTHEAST ARIZONA WITH
SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
ACROSS MOST OF SOUTHEAST ARIZONA. THERE WILL BE A BRIEF DOWNTURN IN
STORM COVERAGE THURSDAY BEFORE A MORE TYPICAL MONSOON PATTERN MOVES
IN BY THIS WEEKEND. EXPECT STRONG...GUSTY AND ERRATIC WINDS WITH THE
STRONGER THUNDERSTORMS. POTENTIALLY HOTTER TEMPERATURES THURSDAY
WITH STRONG HIGH PRESSURE NEARBY...BUT WITH THIS MAY BE MITIGATED
SOMEWHAT BY THE MOISTURE.

&&

.PREV DISCUSSION...STORMS ARE CURRENTLY FORMING ACROSS CENTRAL PIMA
COUNTY AND ACROSS THE RIM. STORM MOTION IS PITIFUL THOUGH...WITH
MAYBE 10 MPH OF WESTERLY MOTION WITH THE FASTER MOVING STORMS. GIVEN
THE DECENT PRECIP WATER VALUES...I AM CONCERNED FOR ISOLATED FLOOD
THREAT. LATEST HRRR SEEMS TO HAVE THE BEST HANDLE ON THE CONVECTION
THUS FAR AND HINTS AT CONVECTION FOCUSED MAINLY ACROSS THE CENTRAL
PORTION OF OUR AREA...OR NEAR THE I-10 CORRIDOR. COULD SEE SOME
MARGINALLY SEVERE STORMS TODAY. BUT THE TALL SKINNY CAPE
PROFILE...ALSO NOTED WITH THE .05 NORMALIZED CAPE VALUE...SUGGEST
LIMITED PARCEL ACCELERATION TODAY SO IT MAY BE DIFFICULT TO SUSTAIN
STRONG A LASTING UPDRAFTS.

I INCREASED TOMORROWS MIN TEMPERATURES IN THE VALLEYS BY A FEW
DEGREES BASED ON MIN TEMPS FROM THIS MORNING. THE NEAR RECORD WARM
LOWS ARE AGAIN POSSIBLE UNLESS CONVECTIVE OUTFLOWS PROVIDE LOCALIZED
COOLING. THE UPPER RIDGE AGAIN DROPS SOUTH TOMORROW AND THE MODELS
RESPOND BY DECREASING THE MID LEVEL MOISTURE. SO CONVECTIVE ACTIVITY
SHOULD BE DOWN...BUT THE TEMPS WILL BE UP AGAIN. MOISTURE SLOWLY
RETURNS FRIDAY AND AN INVERTED TROUGH SHOULD MOVE ACROSS THE AREA
SATURDAY. SO WE CURRENTLY FOCUS THE HIGHEST POPS OVER THE NEXT 7
DAYS ON SATURDAY THINKING THE ADDED LIFT FROM THE INVERTED TROUGH
WILL BE ENOUGH TO OVERCOME THE MARGINAL MOISTURE CONTENT. MOISTURE
CONTENT STARTS TO DISSIPATE SUNDAY BEFORE A MORE PRONOUNCED DRYING
TREND BEGINS MONDAY.

NEXT WEEK...THE LONG WAVE PATTERN SHOWS A HIGH AMPLITUDE RIDGE OVER
THE WEST WITH A DEEP TROUGH OVER THE EAST. THIS TYPE OF BLOCKING
PATTERN CAN GREATLY REDUCE THE PRECIP CHANCES AND PROMOTE WARMER
THAN NORMAL CONDITIONS. CERTAINLY CAN NOT RULE OUT SOME ISOLATED
STORMS NEXT WEEK...BUT I`M MORE CONCERNED FOR THE EXCESSIVE HEAT
POTENTIAL. CURRENT GUIDANCE IS SHOWING SIMILAR TEMPS AS WE
EXPERIENCED THIS WEEK...BUT 850-700MB THICKNESS VALUES SUGGEST WE
MAY BE A FEW DEGREES TOO COOL FOR MAX TEMPS NEXT WEEK.

JJB

&&

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

&&

$$

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MEYER/CERNIGLIA





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