Area Forecast Discussion
Issued by NWS Tucson, AZ

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000
FXUS65 KTWC 210418
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
915 PM MST SUN JUL 20 2014

.SYNOPSIS...EXPECT ISOLATED TO SCATTERED THUNDERSTORMS MOSTLY EAST
AND SOUTH OF TUCSON THROUGH THE MIDDLE OF THIS WEEK. MUCH HOTTER
TEMPERATURES WILL OCCUR TUESDAY THROUGH THURSDAY...WITH NEAR RECORD
HIGHS POSSIBLE. AN INCREASE IN THUNDERSTORM ACTIVITY SHOULD OCCUR
LATE IN THE WEEK AND INTO THE WEEKEND.

&&

.DISCUSSION...04Z SFC TEMPS RANGED FROM THE MID 70S IN COCHISE
COUNTY TO THE MID 90S IN THE WESTERN PIMA COUNTY. A SIMILAR GRADIENT
OF DEWPOINTS WAS PRESENT...FROM NEAR 60 CLOSE TO KDUG DECREASING TO
THE UPPER 30S IN THE WESTERN DESERTS. 04Z IR IMAGERY WAS SHOWING A
DECENT COMPLEX OVER NRN SONORA WHICH WAS SLOWLY MAKING ITS WAY NORTH
INTO EXTREME SERN AZ...WITH A FEW LIGHTNING STRIKES OCCURING ON THE
MEXICAN SIDE OF THE BORDER. SEVERAL OUTFLOWS ARE APPARENT ON RADAR
HEADING TO THE NORTHWEST WITH A FEW WEAK ECHOES POPPING UP NEAR
SIERRA VISTA. AS SUCH...HAVE DECIDED TO LEAVE SLIGHT CHC POPS IN THE
FORECAST ADJACENT TO THE AZ/MEXICO BORDER IN COCHISE COUNTY UNTIL
09Z. OTHERWISE...THE REST OF THE FORECAST LOOKS TO BE IN GOOD SHAPE.
FOR ADDITIONAL INFORMATION...PLEASE SEE THE PREVIOUS DISCUSSION
BELOW.

&&

.AVIATION...VALID THRU 22/06Z.
ISOLATED -TSRA/-SHRA SE OF KTUS MAINLY FROM KFHU TO KDUG ENDING
AROUND 20/09Z. DRY CONDITIONS WILL PREVAIL ELSEWHERE THE REST OF
TONIGHT INTO MONDAY MORNING. ISOLATED -TSRA/-SHRA WILL THEN OCCUR
MOSTLY EAST AND SOUTH OF KTUS MONDAY AFTERNOON AND MONDAY EVENING.
BRIEF WIND GUSTS TO NEAR 35 KTS MAY OCCUR WITH THIS ACTIVITY.
OTHERWISE...CLOUD DECKS FROM KTUS EWD/SWD WILL MOSTLY BE ABOVE 10K
FT AGL OUTSIDE OF TSRA. MOSTLY CLEAR SKIES WILL PREVAIL WEST OF
KTUS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...ISOLATED THUNDERSTORMS SHOULD BE LIMITED TO EAST AND
SOUTH OF TUCSON MONDAY AFTERNOON AND MONDAY EVENING. THUNDERSTORM
ACTIVITY IS THEN EXPECTED TO GRADUALLY SPREAD WESTWARD ACROSS THE
AREA STARTING TUESDAY AND CONTINUE THE REST OF THE WEEK. STRONG HIGH
PRESSURE ALOFT WILL ALSO BRING HOTTER TEMPERATURES TUESDAY THROUGH
THURSDAY.

&&

.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...THE HIGH IS PROGGED TO MEANDER ACROSS THE GENERAL
VICINITY THROUGH MIDWEEK WITH A SIMILAR THREAT FOR ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY OVER THE MOUNTAINS...AS
WELL AS ALONG THE INTERNATIONAL BORDER EACH AFTERNOON AND EVENING.
FROM WEDNESDAY AND BEYOND I DID NOT MAKE ANY ADJUSTMENTS TO THE
INHERITED POP FORECAST DUE TO CONTINUED UNCERTAINTIES THIS TIME OF
YEAR. I INHERITED AN UPSWING IN THUNDERSTORM ACTIVITY
FRIDAY...ESPECIALLY ALONG THE INTERNATIONAL BORDER NEAR NOGALES AND
DOUGLAS. HOWEVER...CONFIDENCE ON THIS HAPPENING IS NOT AS HIGH SINCE
THE LATEST MODEL RUNS SHOW THE RIDGE BUILDING WEDNESDAY AND NEARLY
OVERHEAD FOR THURSDAY AND FRIDAY. PREVIOUS SOLUTIONS WERE SUGGESTING
AN INVERTED TROUGH MOVING WESTWARD ACROSS NORTHERN MEXICO...BUT NOW
THIS FEATURE IS LESS PRONOUNCED AND FARTHER SOUTH. THAT SAID...THE
RAIN CHANCES FOR FRIDAY MAY BE TOO HIGH. OVERNIGHT SHIFT WILL WANT
TO TAKE A CLOSER LOOK AT THIS AFTER RECEIPT OF 00Z MODEL RUNS.

THE BIG STORY HOWEVER IS THE EXPECTED HOT TEMPERATURES DURING THE
MIDDLE TO LATTER PART OF THE WEEK. HIGHS FOR TUCSON EXPECTED TO
POTENTIALLY REACH THE 110 DEG MARK...WITH SLIGHTLY HIGHER READINGS
FOR THE FAR WESTERN DESERTS. HIGH TEMPERATURES WILL BE ABOVE NORMAL
THROUGHOUT THE ENTIRE FORECAST PERIOD...WITH THE WARMEST DAYS
OCCURRING WEDNESDAY AND THURSDAY WHEN HIGHS WILL BE 10 TO 12 DEGS
ABOVE NORMAL...OTHERWISE HIGHS RUNNING ABOUT 4 TO 7 DEGS ABOVE
NORMAL EACH DAY. LOWS GENERALLY 3 TO 5 DEGS ABOVE NORMAL EACH
MORNING.

&&

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

&&

$$

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

DISCUSSION...FRENCH
PREVIOUS DISCUSSION...MOLLERE
FIRE WEATHER/AVIATION...FRANCIS




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