Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 180925
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
230 AM MST SAT OCT 18 2014

.SYNOPSIS...DRY AND WARM TODAY. A WEAK TROUGH OF LOW PRESSURE OVER
THE AREA WILL THEN BRING A CHANCE OF SHOWERS AND A FEW THUNDERSTORMS
MAINLY EAST OF TUCSON THE FIRST HALF OF THE NEW WEEK. HIGH PRESSURE
WILL BRING DRIER CONDITIONS DURING THE LATTER PART OF NEXT WEEK
ALONG WITH SEVERAL DEGREES OF WARMING.

&&

.DISCUSSION...SOUTHWESTERLY FLOW BEHIND SUBTROPICAL IMPULSE NOW
LIFTING DOWNSTREAM THROUGH NEW MEXICO. ANOTHER IMPULSE UNDERCUTTING
THE RIDGE AND LOSING HIGHER LATITUDE SUPPORT PHASING IN FROM
SOUTHERN CALIFORNIA AND NORTHERN BAJA OVER THE NEXT 24 HOURS. IT
STILL WON`T HAVE A LOT OF MOISTURE TO WORK WITH FOR MUCH OF OUR AREA
AS WE CONTINUE TO SEE THE BEST MOISTURE AXIS DRAWN UP THROUGH NEW
MEXICO LATE SUNDAY INTO MONDAY. BEST SHOWER COVERAGE STILL EXPECTED
TO BE EAST OF TUCSON...ESPECIALLY NEAR THE NEW MEXICO BORDER.

AS THE LARGER SCALE RIDGE AXIS SHIFTS EASTWARD WE WILL PICK UP
HIGHER LATITUDE FLOW DIGGING WEAKLY INTO THE REGION TUESDAY AND
WEDNESDAY. THIS SHOULD LIFT AND SHEAR THE WEAK MID LEVEL IMPULSE OUT
OF THE PICTURE BY LATE WEDNESDAY. A GENERAL MODEL ENSEMBLE
COMPROMISE SEEMS TO HANDLE THIS WELL WITH SIMILAR TREATMENT OF THE
FULL LATITUDE TROUGH AS IT NEARS THE WEST COAST AS WELL AS THE
INITIAL WEAK SOUTHERLY SPLIT.

HIGH PRESSURE BUILDING IN ACROSS SOUTHERN CALIFORNIA AND ARIZONA
WILL BRING DRIER CONDITIONS AND A WARMING TREND THE SECOND HALF OF
THE WEEK. AFTERNOON HIGHS CLIMB BACK TO AROUND 6-7 DEGREES ABOVE
CLIMO BY FRIDAY.

&&

.AVIATION...VALID THRU 19/09Z.
A RELATIVELY DRY SOUTHWESTERLY FLOW AHEAD OF A WEAK TROUGH WILL
CONTINUE VFR CONDITIONS ACROSS SE AZ WITH SCT CLOUDS ABOVE 12-15K FT
AGL. SURFACE WIND THROUGH EARLY SUNDAY MORNING WILL EXHIBIT NORMAL
DIURNAL WIND TRENDS GENERALLY LESS THAN 10 KTS. AVIATION DISCUSSION
NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...MOSTLY CLEAR TODAY WITH MODEST MOISTURE. A TROUGH OF
LOW PRESSURE OVER THE AREA IN COMBINATION WITH ADEQUATE MOISTURE
WILL RESULT IN A CHANCE OF SHOWERS AND A FEW THUNDERSTORMS SUNDAY
THROUGH TUESDAY OR WEDNESDAY...MAINLY EAST OF TUCSON. DRY CONDITIONS
WILL THEN OCCUR AREA WIDE THE SECOND HALF OF THE WEEK. 20-FOOT WINDS
WILL BE DIURNAL IN NATURE AND GENERALLY LESS THAN 15 MPH THIS
WEEKEND AND INTO NEXT WEEK.

&&

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

$$

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

MEYER/MEADOWS




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