Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 281112
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
400 AM MST MON JUL 28 2014

.SYNOPSIS...THERE IS A GOOD CHANCE OF THUNDERSTORMS THIS AFTERNOON
AND EVENING FOLLOWED BY DRIER CONDITIONS TUESDAY THROUGH THURSDAY.
INCREASING CHANCES OF THUNDERSTORMS WILL THEN OCCUR FRIDAY THROUGH
SUNDAY AS DEEPER MOISTURE RETURNS TO THE AREA. EXPECT A WARMING
TREND TUESDAY AND WEDNESDAY WITH A MODERATION IN DAYTIME
TEMPERATURES BY THIS WEEKEND.

&&

.DISCUSSION...KEMX WSR-88D DETECTED ISOLATED MOSTLY LESS THAN 30 DBZ
ECHOES MOVING NEWD ACROSS SRN GRAHAM/NERN COCHISE COUNTIES AT 1055Z.
THE REST OF SE AZ WAS VOID OF PRECIP ECHOES AT THIS TIME. CLOUD TOPS
HAVE WARMED CONSIDERABLY DURING THE PAST 2-3 HOURS AS PER IR
SATELLITE IMAGERY. A CYCLONIC CIRCULATION FEATURE CENTERED OVER NRN
COCHISE COUNTY WAS EVIDENT VIA RADAR/SATELLITE IMAGERY.

THERE WERE PRONOUNCED DIFFERENCES BETWEEN THE 28/06Z NAM AND SEVERAL
RUC HRRR SOLUTIONS REGARDING PRECIP POTENTIAL INTO THIS AFTERNOON.
THE RUC HRRR HAS BEEN VERY CONSISTENT WITH LIMITING PRECIP ECHOES TO
NEAR THE ERN MOUNTAINS FROM LATE THIS MORNING INTO EARLY THIS
AFTERNOON. HOWEVER...THE NAM DEPICTS FAIRLY MODEST QPF/S TO OCCUR
FROM TUCSON EWD TO THE NEW MEXICO BORDER BY LATE THIS MORNING AND
CONTINUE INTO THIS AFTERNOON. DRY CONDITIONS WERE PROGGED ACROSS WRN
PIMA COUNTY.

A KEY ELEMENT REGARDING SHOWER/TSTM POTENTIAL LATER TODAY MAY BE THE
INFLUENCE FROM THE AFOREMENTIONED CYCLONIC CIRCULATION SYSTEM. A
SUBSIDENCE AREA MAY OCCUR AS THIS FEATURE DEPARTS NWD INTO EAST
CENTRAL ARIZONA. THIS SCENARIO WOULD GIVE CREDENCE TO THE VARIOUS
RUC HRRR SOLUTIONS. HOWEVER...GIVEN THE ONGOING DECREASING CLOUD
COVER...THE COMBINATION OF AMPLE MOISTURE WITH FAIRLY STOUT
INSOLATION MAY LEAD TO GREATER COVERAGE OF SHOWERS/TSTMS AS PER THE
MOST RECENT NAM SOLUTION.

THE OFFICIAL FORECAST FOR THIS MORNING GIVES GENERALLY A SLIGHT
CHANCE OF SHOWERS/TSTMS ACROSS THE ERN MOUNTAINS FOLLOWED BY
SCATTERED TO NUMEROUS SHOWER/TSTMS THIS AFTERNOON INTO THIS EVENING.
FAIRLY SLOW STORM MOTIONS SHOULD TRANSLATE INTO LOCALLY HEAVY
RAINFALL. A FEW GUSTS MAY BRIEFLY APPROACH SEVERE THRESHOLDS THIS
AFTERNOON INTO EARLY THIS EVENING. A SLIGHT CHANCE OF SHOWERS/TSTMS
WILL THEN OCCUR LATE TONIGHT.

TUE-THUR...
28/00Z GFS/ECMWF WERE SIMILAR WITH DEPICTING A DRYING TREND AS WLY/
NWLY MID-LEVEL IS PROGGED TO OCCUR. THE LEAST COVERAGE OF SHOWERS/
TSTMS SHOULD OCCUR WED ASSUMING THE GFS/ECMWF SOLUTIONS TO BE
REALITY.

FRI-SUN...
GFS/ECWMF WERE SIMILAR WITH DEPICTING INCREASING MOISTURE ACROSS SE
AZ AS THE UPPER HIGH BECOMES CENTERED NEAR THE FOUR CORNERS REGION.
HAVE NOTED THAT THESE SOLUTIONS HAVE DEPICTED REDUCED QPF/S...
PARTICULARLY THIS WEEKEND...VERSUS GFS/ECMWF SOLUTIONS FROM 24 HOURS
AGO. AT ANY RATE...FORECAST CONFIDENCE IS FAIRLY HIGH THAT DEEPER
MOISTURE WILL LEAD TO SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS/
TSTMS.

HIGH TEMPS THIS AFTERNOON WILL GENERALLY BE SIMILAR TO TEMPS
ACHIEVED SUN AFTERNOON. A WARMING TREND WILL THEN OCCUR TUE-WED
FOLLOWED BY A MODERATION IN DAYTIME TEMPS BY THIS WEEKEND.

&&

.AVIATION...VALID THRU 29/12Z.
A FEW -TSRA/-SHRA WILL OCCUR MAINLY NEAR THE MOUNTAINS EAST OF KTUS
THIS MORNING...THEN SCATTERED TO NUMEROUS TSRA/SHRA WILL PREVAIL
THIS AFTERNOON INTO THIS EVENING. MVFR CONDITIONS WILL OCCUR WITH
THE STRONGER TSRA ALONG WITH WIND GUSTS TO AROUND 45 KTS. CLOUD
DECKS WILL GENERALLY BE AT 7-12K FT AGL THRU EARLY TUESDAY MORNING.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...SCATTERED TO NUMEROUS THUNDERSTORMS WILL OCCUR THIS
AFTERNOON AND EVENING. EXPECT STRONG...GUSTY AND ERRATIC WINDS
ASSOCIATED WITH THE STRONGER STORMS. DRIER CONDITIONS WILL THEN
PROVIDE DECREASED THUNDERSTORM ACTIVITY TUESDAY THROUGH THURSDAY.
THEREAFTER...SCATTERED MOSTLY AFTERNOON AND EVENING THUNDERSTORMS
WILL PREVAIL FRIDAY THROUGH SUNDAY AS DEEPER MOISTURE RETURNS TO THE
AREA. OTHERWISE...NORMAL DIURNAL WIND TRENDS WILL OCCUR WITH
OCCASIONAL GUSTS DURING THE AFTERNOON HOURS DUE TO DAYTIME HEATING.

&&

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

&&

$$

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