Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 101550
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
850 AM MST THU JUL 10 2014

.SYNOPSIS...STORM COVERAGE AND INTENSITY ARE EXPECTED TO INCREASE
OVER THE WEEKEND AS ENERGY APPROACHES THE AREA FROM THE EAST.
OTHERWISE...EXPECT A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS
INTO NEXT WEEK. MOST STORMS WILL OCCUR DURING AFTERNOON AND EVENING
HOURS BUT SOME WILL LINGER OVERNIGHT AT TIMES. SOME STORMS WILL BE
ACCOMPANIED BY LOCALLY HEAVY RAINFALL AND STRONG WINDS.

&&

.DISCUSSION...WATER VAPOR IMAGERY AND 10/12Z UPPER-AIR PLOTS SHOW
HIGH PRESSURE ALOFT JUST TO OUR EAST OVER NEW MEXICO...RESULTING IN
SOUTHERLY MID LEVEL FLOW ACROSS MUCH OF ARIZONA AS EVIDENCED IN THIS
MORNINGS KTWC SOUNDING WHICH SHOWS WEAK FLOW AT THE SURFACE UP TO
AROUND 775MB...THEN 10-25 KNOTS IN THE 700-500MB LAYER...GIVING US A
STEERING FLOW FROM THE SOUTH AT AROUND 15 KNOTS FOR STORMS THAT
DEVELOP TODAY. MOISTURE WAS HIGH WITH A PRECIPITABLE WATER VALUE OF
1.63 INCHES. THE UNMODIFIED SOUNDING SHOWS A LIFTED INDEX OF AROUND
MINUS 5 AND A CAPE OF AROUND 1700 J/KG. MODIFYING THE SOUNDING USING
T=97:TD=58 YIELDS A SIMILAR LI AND A CAPE OF AROUND 1400-1500 J/KG.

THAT SAID...THE U OF A WRF/NAM SHOWS CONVECTION DEVELOPING OVER THE
RIM COUNTY AND THE WHITE MOUNTAINS AT AROUND NOON TODAY...WITH
DEVELOPMENT ALSO OVER THE MOUNTAINS ELSEWHERE. BY AROUND 20-21Z (1-2
PM)...ISOLATED TO SCATTERED STORMS DEVELOP ALONG THE INTERNATIONAL
BORDER FROM WEST OF NOGALES AND EASTWARD TO THE NEW MEXICO BORDER
AND THIS ACTIVITY INCREASES SLIGHTLY IN COVERAGE AND SPREADS TO THE
NORTH AND NORTHWEST REACHING EASTERN PIMA COUNTY BY AROUND 5 PM THIS
AFTERNOON...BUT QUICKLY MOVES INTO EASTERN PINAL COUNTY BY 6 PM...
WITH MOST OF THE ACTIVITY WELL TO THE NORTHWEST OF THE AREA BY
AROUND 10 PM. INHERITED POP FORECAST SEEMS TO REFLECT THIS NOTION
WELL...SO NOT PLANNING ON MAKING ANY CHANGES TO THE POP FORECAST AT
THIS TIME.

AS OF 15Z (8 AM MST)...TEMPERATURES RANGED FROM THE LOWER 70S TO THE
MID 80S...WITH THE TUCSON INTL AIRPORT REPORTING A TEMP OF 82
DEGS...AFTER A MORNING LOW OF 77 DEGS. THE CURRENT HOURLY
TEMPERATURE GRIDS ARE MOSTLY ON TRACK WITH EXPECTED/INHERITED
AFTERNOON HIGH TEMPERATURES...SO NO CHANGES ARE PLANNED TO TEMPS
EITHER...BUT WILL CONTINUE TO MONITOR.

FOR DETAILS REGARDING THE FORECAST BEYOND TODAY...PLEASE REFER TO
THE PREVIOUS DISCUSSION BELOW AND STAY TUNED FOR THE AFTERNOON
DISCUSSION...WHICH WILL HAVE MORE INSIGHT REGARDING THE WEATHER FOR
THE UPCOMING WEEKEND.

&&

.AVIATION...VALID THRU 11/12Z.
SLOW CLEARING THROUGH THE MORNING HOURS. EXPECT SCATTERED TSRA/SHRA
MAINLY EAST AND SOUTH OF KTUS THIS AFTERNOON AND EVENING...WITH
LESSER COVERAGE OF SHOWERS/THUNDERSTORMS WEST OF KTUS. MVFR
VISIBILITIES WILL OCCUR WITH +TSRA...AS WELL AS POTENTIAL WIND GUSTS
MOSTLY AROUND 40 KTS. OTHERWISE...CLOUD DECKS WILL BE AROUND 8-15K
FT AGL. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...MOISTURE WILL REMAIN SUFFICIENT TO PROVIDE SCATTERED
TO PERHAPS NUMEROUS MAINLY AFTERNOON AND EVENING THUNDERSTORMS INTO
NEXT WEEK.

&&

.PREVIOUS DISCUSSION...STILL SOME DEBRIS CLOUD PRIMARILY FROM
EARLIER CONVECTION SOUTH OF THE BORDER. COVERAGE MORE LIMITED THE
PAST 18 HOURS AS EXPECTED WITH AN EMPHASIS ON MOUNTAINS AND
EAST/SOUTHEAST ZONES. DEEP MOISTURE STILL IN PLACE BUT WE HAVE LOST
ANY CLEAR TRIGGERS AND ORGANIZERS OTHER THAN SIMPLE SOLAR INSOLATION
FOR THE TIME BEING. WE`RE PROBABLY LOOKING AT ANOTHER DAY THAT
EMPHASIZES MOUNTAINS AND SOUTHERN LOCATIONS INCLUDING COCHISE AND
SANTA CRUZ COUNTIES.

STARTING TO FOCUS MORE AND MORE ON A BUSY WEEKEND WITH A STRONG
EASTERLY WAVE APPROACHING ACROSS FAR SOUTHERN TEXAS AND NORTHERN
MEXICO...INTO CHIHUAHUA/SONORA/SOUTHEAST ARIZONA SATURDAY AFTERNOON
INTO SUNDAY EVENING. LOW TO MODERATE COVERAGE AND INTENSITY UNTIL
THEN...BUT A BUSY WEEKEND.

&&

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

&&

$$

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

CURRENT DISCUSSION...MOLLERE
PREVIOUS DISCUSSION...MEYER






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