Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 090405
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
905 PM MST MON FEB 8 2016

.SYNOPSIS...DRY AND MUCH WARMER THIS WEEK WITH AFTERNOON HIGHS WELL
ABOVE AVERAGE FOR FEBRUARY.

&&

.DISCUSSION...WATER VAPOR IMAGERY AND 09/00Z UPPER-AIR PLOTS SHOW A
HIGHLY AMPLIFIED TROUGH OVER THE EASTERN HALF OF THE NATION AND A
RIDGE OVER THE WEST. MEANWHILE...A WEAK LOW PRESSURE SYSTEM RESIDES
OVER THE GENERAL VICINITY OF SOUTH CENTRAL BAJA. EXTENSIVE
CLOUDINESS COVERS A LARGE PART OF SONORA AND CHIHUAHUA MEXICO AND
AREAS FARTHER SOUTH. THE NORTHERN FRINGES OF THESE MOSTLY THIN HIGH
CLOUDS ARE JUST SOUTH OF THE ARIZONA AND NEW MEXICO BORDER WITH
SKIES GENERALLY CLEAR ACROSS ALL OF ARIZONA.

AS OF 04Z (9 PM MST)...TEMPERATURES ACROSS THE REGION RANGED FROM
THE LOWER 50S TO THE MID 60S...WITH THE TUCSON INTL AIRPORT
REPORTING A TEMP OF 64 DEGS AFTER ACHIEVING AN AFTERNOON HIGH OF 81
DEGS...WHICH TIED THE RECORD FOR THIS DATE. THE OLD RECORD WAS SET
BACK IN 2006. IN ADDITION...TODAYS HIGH WAS 13 DEGS ABOVE NORMAL FOR
THIS DATE.

THE CURRENT TEMP READINGS SEEM TO BE RIGHT ON TRACK WITH THE
INHERITED OVERNIGHT LOWS...SO NO CHANGES ARE PLANNED AT THIS
TIME...BUT WILL CONTINUE TO MONITOR THROUGH THE EVENING AND WILL
MAKE ADJUSTMENTS IF WARRANTED.

SEE PREVIOUS DISCUSSION FOR DETAILS BEYOND TONIGHT.

&&

.AVIATION...VALID THRU 10/06Z.
VFR WITH SCT CIRRUS AOA 25K FT AGL. SFC WIND WILL MAINTAIN A SELY TO
NELY DIRECTION AT 5-15 KTS WITH AFTERNOON GUSTS UP TO 20 KTS.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...HIGH PRESSURE WILL BRING DRY CONDITIONS WITH WELL
ABOVE AVERAGE HIGH TEMPERATURES THIS WEEK. EASTERLY 20-FT WINDS WILL
ALSO CONTINUE...WITH SPEEDS OF 10 TO 15 MPH AND OCCASIONAL AFTERNOON
GUSTINESS TO AROUND 25 MPH IN AREAS THAT FAVOR EAST WINDS. ALTHOUGH
RED FLAG CONDITIONS ARE NOT ANTICIPATED...DAYTIME MINIMUM RELATIVE
HUMIDITY VALUES WILL BE IN THE UPPER SINGLE DIGITS AND TEENS INTO
NEXT WEEKEND.

&&

.PREV DISCUSSION...PERSISTENCE IS A POWERFUL FORECAST TOOL. STRONG
HIGH PRESSURE WILL CONTINUE TO DOMINATE OUR WEATHER INTO THE COMING
WEEKEND. EXPECT UNSEASONABLE HEIGHT AND THICKNESS VALUES TO BRING
AFTERNOON HIGHS AS MUCH AS 12 TO 15 DEGREES ABOVE AVERAGE. DRY AND
MORE DRY WITH ONLY SOME PATCHES OF CIRRUS ON THE NORTHERN FRINGE OF
A WEAK DISTURBANCE DIRTYING UP THE BASE OF THE RIDGE TO OUR SOUTH.
WITH THIS LARGER SCALE PATTERN THE RIDGE IS GOING TO BE RATHER
STUBBORN FOR SEVERAL DAYS WITH SE AZ ON THE PROTECTED FRONT FLANK OF
THE RIDGE.

AT THE SURFACE WE WILL SEE A PERSISTENT SURFACE HIGH WITH POSITIONS
RANGING FROM THE CENTRAL BASIN TO THE FRONT RANGE OF THE ROCKIES.
WHENEVER WE HAVE A FRONT RANGE POSITION IT CAN ENHANCE AN EASTERLY
RETURN FLOW FROM NEW MEXICO AND LEAD TO BREEZY CONDITIONS AT TIMES.

PATTERN CHANGE IN THE OFFING THE SECOND HALF OF NEXT WEEK. AN AREA
OF CONVECTION TRANSITIONING OUT OF THE CENTRAL PACIFIC IS HINTING AT
A CONSOLIDATION OF A SOUTHERN BRANCH SPLIT WITH GREATER POTENTIAL
FOR WET TRAJECTORY STORMS TO AFFECT SE AZ AFTER THE 17TH. ECMWF
ENSEMBLE MEAN AND SPREAD TRENDS AT 200-240 HOURS CONTINUE TO
REASONABLY SHOW THE RESULTING TRANSITION WITH THE THE GEFS
SUBSEQUENTLY CONTINUING TO SHOW A FAVORABLE CONSOLIDATION OF THE
500MB 5760M ISOBAR INTO A TROUGH AND THEN ZONAL CONFIGURATION AT 240-
312 HOURS. THIS WOULD SUGGEST CONTINUED VULNERABILITY TO STORMS OFF
THE EASTERN PACIFIC AFTER AN INITIAL TRANSITION STORM THE SECOND
HALF OF NEXT WEEK. THE GFS IS EVEN SUGGESTING A SUBTROPICAL
INFLUENCE INTO THE TRANSITION STORM...BUT AT THIS POINT IT`S UNCLEAR
IF THAT WILL BE MORE OF AN ISSUE FOR US OR NEW MEXICO. THE POINT IS
THE PATTERN WILL BECOME MORE FAVORABLE FOR STORMS BY LATER NEXT WEEK
WITH A SMALL CHANCE OF WEAK SUBTROPICAL INFLUENCES FROM THE
SOUTHWEST AS EARLY AS TUESDAY. YOUR MILEAGE MAY VARY.

&&

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

&&

$$

CURRENT DISCUSSION...MOLLERE
PREVIOUS DISCUSSION...MEYER/RASMUSSEN

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


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