Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 182139
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
230 PM MST FRI JUL 18 2014

.SYNOPSIS...DRIER AIR WILL LIMIT THUNDERSTORM COVERAGE AGAIN TODAY.
A MOISTURE INCREASE OVER THE WEEKEND IS EXPECTED TO BRING BETTER
THUNDERSTORM COVERAGE BACK TO SOUTHEAST ARIZONA. HOWEVER...MUCH OF
NEXT WEEK MAY SEE BELOW AVERAGE MOISTURE. MUCH HOTTER TEMPERATURES
ARE FORECAST FOR TUESDAY THROUGH THURSDAY...WITH NEAR RECORD HIGHS
POSSIBLE. WE SHOULD THEN SEE A MARKED INCREASE IN THUNDERSTORM
ACTIVITY ONCE AGAIN BY THE END OF THE WEEK.

&&

.DISCUSSION...MARGINAL MOISTURE AGAIN TODAY BUT SOME SIGNS OF
IMPROVEMENT. 12Z KTWC SOUNDING HAD PRECIPITABLE WATER BETWEEN 1 AND
1.1 INCHES...BUT CURRENT BLENDED SATELLITE ESTIMATES ARE CLOSER TO
1.2 INCHES. SURFACE DEWPTS ARE UP 4 TO 8 DEGREES COMPARED TO 24
HOURS AGO IN MOST LOCATIONS...GENERALLY IN THE UPPER 40S TO MIDDLE
50S.

ACTIVITY IS INCREASING ACROSS NORTHERN SONORA TODAY WITH 1.5 INCH PW
VALUES PUSHING FROM SOUTHERN SONORA INTO CENTRAL SONORA. GUAYMAS
SOUNDING SHOWED SOUTHERLY FLOW INCREASING OVER THE PAST 24 TO 36
HOURS...5K FEET DEEP AT 12Z BUT STILL ONLY 8 TO 10 KTS. KYUX (YUMA)
VAD WIND PROFILE NOW SHOWING AN INCREASING SOUTHERLY COMPONENT AS
WELL...ALSO ONLY 5-10 KTS FROM THE S-SE. HOWEVER...IT WAS AROUND 4K
FEET DEEP THIS MORNING AND IS CURRENTLY UP TO 6-7K FEET DEEP. STILL
THAT`S NOT TERRIBLY STRONG AND SURFACE DEWPTS THAT HAD JUMPED BACK
INTO THE 60S EARLIER ARE NOW BACK INTO THE MIDDLE 50S TO UPPER 40S.
CURRENTLY STILL EXPECTING ISOLATED MOUNTAIN AND BORDER ACTIVITY THIS
AFTERNOON AND EVENING. WITH SOUTHEASTERLY FLOW...THE CONVECTION IN
NORTHERN SONORA WILL TRY TO PUSH INTO SE AZ THIS EVENING WITH
OVERNIGHT ECHOES POSSIBLE ON THE RADAR.

THE IMPULSE EVIDENT ON WATER VAPOR IMAGERY PUSHING THROUGH SONORA
AND THE NORTHERN GULF OF CALIFORNIA WILL PROBABLY HELP ANY POSSIBLE
OVERNIGHT TO EARLY MORNING ACTIVITY. SOME SUBSIDENCE BEHIND THIS
FEATURE POSSIBLE DURING THE DAY TOMORROW FOR OUR PART OF THE
STATE...BUT WE SHOULD STILL FIRE NEAR THE BORDER DURING THE
AFTERNOON AND HAVE A DECENT CHANCE TO PUSH A FEW STORMS INTO THE
TUCSON AREA LATE SATURDAY AFTERNOON OR EARLY EVENING. OVERALL
COVERAGE FOR THE WEEKEND SHOULD BE UP COMPARED TO YESTERDAY AND
TODAY...BUT NOT AS BUSY AS WHAT WE SAW FOR THE FIRST HALF OF JULY.

STILL LOOKING AT HOTTER TEMPERATURES BY THE MIDDLE OF NEXT WEEK WITH
A VERY STRONG RIDGE BUILDING THROUGH THE DESERT SOUTHWEST. NEAR
RECORD LEVELS ARE POSSIBLE WEDNESDAY AND THURSDAY AS WE STILL
STRUGGLE WITH AVAILABLE MOISTURE. WE MIGHT END UP NEAR EXCESSIVE
HEAT LEVELS WITH BOTH ECMWF AND GFS THICKNESSES SUPPORTING
TEMPERATURES ABOVE 110 AT TUCSON WEDNESDAY AND THURSDAY. BY THURSDAY
OR FRIDAY THIS SHOULD HELP SET UP A DEEP MOISTURE SURGE AND KNOCK
THE TEMPERATURES BACK CLOSER TO CLIMO BY FRIDAY AND SATURDAY NEXT
WEEK.

&&

.AVIATION...ISOLATED TSRA/SHRA EAST AND SOUTH OF KTUS THIS AFTERNOON
AND EVENING WITH DRY CONDITIONS ELSEWHERE. MVFR VISIBILITIES MAY
OCCUR WITH THE STRONGER TSRA...AS WELL AS WIND GUSTS TO AROUND 40
KTS. CLOUD BASES ASSOCIATED WITH TSRA/SHRA AT 6-8K FT AGL. CLEARING
TRENDS AFTER 19/05Z. BREEZY SURFACE WIND IN THE GILA RIVER VALLEY IN
THE VICINITY OF KSAD...WITH WLY/NWLY SURFACE WIND AT 14-18 KTS THIS
AFTERNOON/EARLY EVENING. OTHERWISE...OUTSIDE OF TSRA...LIGHT SURFACE
WIND GENERALLY AT 12 KNOTS OR LESS. AVIATION DISCUSSION NOT UPDATED
FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...ISOLATED SHOWERS AND THUNDERSTORMS WILL OCCUR THIS
AFTERNOON AND EVENING...MAINLY NEAR THE INTERNATIONAL BORDER AND IN
THE EASTERN MOUNTAINS NEAR THE NEW MEXICO BORDER...WITH RELATIVELY
DRY CONDITIONS ELSEWHERE. EXPECT SOME GUSTY WINDS TODAY AND SATURDAY
IN THE UPPER GILA RIVER VALLEY AROUND SAFFORD. A MORE FAVORABLE FLOW
PATTERN WILL THEN OCCUR FOR SHOWER AND THUNDERSTORM DEVELOPMENT
SATURDAY THROUGH MONDAY. THEREAFTER...HIGH PRESSURE ALOFT WILL
STRENGTHEN OVER THE REGION MID TO LATE NEXT WEEK...RESULTING IN
HOTTER TEMPERATURES...ESPECIALLY WEDNESDAY AND THURSDAY.

&&

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

&&

$$

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