Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 012119
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
215 PM MST MON SEP 1 2014

.SYNOPSIS...HOT AND DRY TO START THE WEEK. THE CHANCE OF
THUNDERSTORMS WILL INCREASE WEDNESDAY INTO THE WEEKEND AS MOISTURE
INCREASES ACROSS THE AREA.

&&

.DISCUSSION...STILL UNSEASONABLY DRY TO START SEPTEMBER WITH
PRECIPITABLE WATER VALUES AROUND .7 OF AN INCH (ABOUT 55 PERCENT OF
NORMAL) AND SURFACE DEW POINTS HANGING ON TO VALUES IN THE 40S TO
LOWER 50S.

MUCH DEEPER MOISTURE JUST SOUTH OF US THROUGH CENTRAL AND SOUTHERN
SONORA WITH A DEEPER FETCH BUILDING UP THE GULF OF CALIFORNIA AS
WELL. ORGANIZED CONVECTION JUST SOUTH OF THE GULF HELPING SURGE
ACTIVITY THROUGH THE CENTRAL GULF. THIS IS FURTHER PRIMING THE
REGION IMMEDIATELY SOUTH OF US AND KEEPING THINGS ON TRACK FOR
MOISTURE SEEPING BACK IN FROM THE SOUTH AS HIGH PRESSURE SETS UP
EAST OF THE AREA BY WEDNESDAY AND THURSDAY.

TROPICAL INFLUENCES ARE STARTING TO LOOK EVEN MORE IMPRESSIVE FOR
THE WEEKEND INTO EARLY NEXT WEEK AS A DISTURBANCE NEAR THE SOUTHWEST
COAST OF MEXICO AROUND 15N IS EXPECTED TO SLOWLY ORGANIZE OVER THE
NEXT 5 DAYS INTO A TROPICAL CYCLONE (NORBERT) AND PUSH TOWARD THE
SOUTHERN TIP OF BAJA. THIS WOULD BE A FAVORABLE POSITION TO STRONGLY
REINFORCE THE NORTHWARD MOISTURE PUSH. 12Z MEDIUM RANGE MODELS
REFLECT THIS VERY WELL BY NEXT WEEKEND AND EARLY NEXT WEEK. WE
CONTINUE TO INCREASE THE SHOWER AND THUNDERSTORM COVERAGE TREND THE
SECOND HALF OF THE WEEK INTO NEXT WEEKEND...WITH AN EMPHASIS ON LATE
SATURDAY INTO MONDAY. AFTER A COUPLE OF AVERAGE THUNDERSTORM DAYS
LATE IN THE WEEK...IT`S STARTING TO LOOK PRETTY WET NEXT WEEKEND
INTO EARLY NEXT WEEK.

A LITTLE FURTHER OUT...ECMWF HAS A VERY INTERESTING WEST COAST
TROUGH RESOLUTION THAT DRAWS THE REMNANT LOW FROM THE TROPICAL
SYSTEM INTO SOUTHERN ARIZONA AROUND THE MIDDLE OF NEXT WEEK. YEAH
THAT`S DAYS 8-9 BUT YEOW. CPC 6-10 DAY OUTLOOK FOR CALLING FOR
ELEVATED PROBABILITY OF ABOVE NORMAL PRECIP FOR THE SATURDAY TO
WEDNESDAY PERIOD IS LOOKING SOLID.

&&

.AVIATION...VALID THRU 02/23Z.
FEW-SCT CLOUDS WITH BASES AT 9-13K FT AGL MAINLY EAST OF A KOLS-KSAD
LINE THROUGH THE EARLY EVENING HOURS TONIGHT AND THEN AGAIN TUESDAY
AFTERNOON. OTHERWISE...SKC CONDITIONS. WLY/NWLY SURFACE WIND AT 10
TO 15 KTS THRU 02/02Z...THEN SURFACE WIND LESS THAN 10 KTS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...DRY AND WARM CONDITIONS ARE EXPECTED THROUGH
TUESDAY. THERE WILL BE A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
ALONG THE INTERNATIONAL BORDER SOUTH AND SOUTHEAST OF TUCSON
WEDNESDAY. SHOWER AND THUNDERSTORM CHANCES WILL THEN INCREASE
THURSDAY THROUGH THE UPCOMING WEEKEND AS MOISTURE INCREASES ACROSS
THE AREA. 20-FOOT WINDS WILL BE WEST/NORTHWEST AT 10 TO 15 MPH
DURING THE AFTERNOON HOURS THE NEXT FEW DAYS...AND DIURNALLY/TERRAIN
DRIVEN AT LESS THAN 10 MPH THE REST OF THE DAY.

&&

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

&&

$$

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

MEYER/ZELL






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