Area Forecast Discussion
Issued by NWS Tucson, AZ

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS65 KTWC 050419
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
919 PM MST FRI SEP 4 2015

.SYNOPSIS...A MOIST ATMOSPHERE WILL REMAIN IN PLACE THROUGH THIS
WEEKEND...WITH ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS THROUGH SUNDAY. A GRADUALLY REDUCTION IN
AREAL COVERAGE OF STORMS WILL OCCUR EARLY NEXT WEEK. BELOW NORMAL
DAYTIME TEMPERATURES WILL PREVAIL THROUGH THIS WEEKEND...WITH HIGH
TEMPERATURES RETURNING CLOSE TO SEASONAL NORMALS BY THE MIDDLE OF
NEXT WEEK.

&&

.DISCUSSION...IT FELT LIKE AN OCTOBER DAY OUT THERE TODAY...WITH
TUCSON RECORDING ITS COOLEST HIGH TEMPERATURE SINCE WAY BACK ON MAY
24TH (83 DEGREES F). CURRENTLY...KEMX RADAR SHOWS JUST LIGHT SHOWERS
CONTINUING MAINLY SOUTH AND EAST OF TUCSON WITH TRENDS TOWARDS
SLOWLY DECREASING COVERAGE. IR SATELLITE LOOPS SHOW MOSTLY CLOUDY TO
CLOUDY SKIES AREA-WIDE...WHICH SHOULD PERSIST THROUGH THE OVERNIGHT
HOURS HELPING TO TEMPER OUR LOWS SOMEWHAT. STILL...ANOTHER COOL
MORNING IS ON TAP TOMORROW WITH BELOW-NORMAL LOWS.

BASED ON SATELLITE AND RADAR TRENDS...AS WELL AS A GLANCE AT THE
RECENT RAP...UNIV OF AZ. WRF-NAM...AND NAM12...DROPPED POPS OUT WEST
BUT WILL KEEP A MENTION OF AT LEAST ISOLATED SHOWERS THROUGH THE
OVERNIGHT PERIOD BASICALLY FROM TUCSON AND POINTS SOUTH AND EAST
WHERE SOME SUBTLE RIPPLES IN THE FLOW MAY OFFER ENOUGH DYNAMIC
SUPPORT TO CONTINUE LIGHT PRECIP THERE INTO THE MORNING HOURS.

TOMORROW MAY ONCE AGAIN BE FAIRLY SUBDUED WEATHER-WISE AS POOR MID-
LEVEL LAPSE RATES AND CLOUD COVER LIMITS OUR OVERALL INSTABILITY.
THAT SAID...THE 05/02Z RAP AND NAM12 INDICATE WE MAY GET SOME
ASSISTANCE FROM WEAK MID-LEVEL FEATURES...AND THE UPPER-LEVEL FLOW
MAY BECOME A TOUCH MORE DIFFLUENT OVERALL.

&&

.AVIATION...VALID THRU 06/06Z.
ISOLATED TO SCATTERED -SHRA WILL PERSIST OVERNIGHT BUT CONTINUE TO
GRADUALLY DECREASE IN COVERAGE SOUTH AND EAST OF KTUS. EXPECT BKN-
OVC CLOUDS AT 9-12 KFT AGL. ISOLATED TO PERHAPS SCATTERED
-SHRA/-TSRA DEVELOPING TOMORROW AFTER ABOUT 05/20Z. BRIEF MVFR
CONDITIONS POSSIBLE IN AND AROUND THE STRONGEST STORMS. OUTSIDE OF
THUNDERSTORM WIND GUSTS...SURFACE WINDS WILL GENERALLY BE LESS THAN
10 KTS AND MAINTAIN A MORE SOUTHERLY COMPONENT THAN USUAL DURING
THE AFTERNOON. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...MOIST CONDITIONS WILL LINGER THROUGH THE NEXT 24
HOURS OVER EASTERN AREAS WITH HIGH TEMPERATURES BELOW NORMAL AND
GOOD RH RECOVERY AREA WIDE. WINDS WILL FAVOR A SOUTHERLY
DIRECTION...BUT WILL BE LIGHT ENOUGH TO SEE STRONG TERRAIN
INFLUENCES. AFTERNOON SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN
IN THE FORECAST THROUGH THE HOLIDAY WEEKEND.

&&

.PREV DISCUSSION...A FEW LINGERING LIGHT SHOWERS ARE POSSIBLE
OVERNIGHT. SCATTERED SHOWERS AND THUNDERSTORMS SHOULD FIRE UP AGAIN
ON SATURDAY AFTERNOON AS MOISTURE CONTINUES TO HANG AROUND.

THEREAFTER...THE TROUGH CURRENTLY LOCATED IN THE PAC NW WILL SWING
EWD THRU THE NRN ROCKIES. SWLY FLOW WILL CONTINUE OVER THE AREA
THROUGH SUNDAY...AND IN CONJUNCTION WITH A BREAK BETWEEN TROPICAL
SYSTEMS...WILL USHER IN SOME DRIER AIR. THIS SLIGHT DOWNTURN IN
ACTIVITY WILL BE SHORT LIVED AS THE NEXT TROPICAL SYSTEM BEGINS TO
PUSH MOISTURE NORTHWARD INTO SE AZ EARLY NEXT WEEK. BY MIDWEEK...THE
UPPER LEVEL JET IS FAIRLY ZONAL FOR A SHORT TIME AND LOCATED NEAR
THE CANADIAN BORDER...ALLOWING FOR WESTERLY FLOW ACROSS THE DESERT
SW. THE TIMING AND LOCATION FOR THE BEST PRECIP CHANCES WILL BE
HIGHLY DEPENDENT ON THE TRACK OF THIS NEXT TROPICAL SYSTEM. THAT
SAID...ONLY MINOR CHANGES WERE MADE TO INHERITED POPS THROUGH THE
MIDDLE OF NEXT WEEK.

LATE NEXT WEEK...BOTH THE 04/12Z GFS/ECMWF INDICATED NWLY FLOW
RETURNING TO THE AREA...WITH RIDGING IN THE WEST AND A TROF DIGGING
THROUGH THE GREAT LAKES REGION. THIS SHOULD HELP TO DRY THINGS OUT
WITH THE CAVEAT BEING ANY LINGERING TROPICAL MOISTURE. FOR
NOW...HAVE MAINTAINED JUST SLIGHT CHANCES FOR PRECIP FOR SRN/ERN
ZONES.

TEMPERATURES THIS WEEKEND WILL REMAIN BELOW NORMAL...FOLLOWED BY A
GRADUAL WARMING TREND TO NEAR-NORMAL LEVELS BY THE MIDDLE OF NEXT
WEEK.

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

&&

$$

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

DISCUSSION...CARLAW
PREV DISCUSSION...FRENCH/CANTIN



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.