Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 150856
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
156 AM MST WED OCT 15 2014

.SYNOPSIS...DRY CONDITIONS WITH GENERALLY ABOVE NORMAL DAYTIME
TEMPERATURES WILL PREVAIL THROUGH THURSDAY. A WEAK AREA OF LOW
PRESSURE MAY THEN BRING A FEW SHOWERS ACROSS THE HIGHER TERRAIN EAST
OF TUCSON THIS WEEKEND AND EARLY NEXT WEEK.

&&

.DISCUSSION...WATER VAPOR IMAGERY AND 15/00Z UPPER-AIR PLOTS
INDICATE THE RIDGE AXIS EXTENDS FROM THE SONORA/CHIHUAHUA BORDER
THEN NORTH ACROSS WESTERN NEW MEXICO...INTO COLORADO AND THE
NORTHERN ROCKIES/PLAINS STATES. MEANWHILE...AN UPPER LOW RESIDES
OVER THE COASTAL WATERS OF THE PACIFIC NORTHWEST WITH A SHORTWAVE
TROUGH OVER THE OPEN WATERS OF THE EASTERN PACIFIC WELL TO THE WEST
OF SOUTHERN BAJA. WV AND IR IMAGERY SHOW PLENTY OF MOISTURE OUT
AHEAD OF THESE TWO FEATURES THAT EXTEND FROM MUCH OF THE EASTERN
PACIFIC THROUGH SOUTHERN CALIFORNIA...MUCH OF NEVADA AND INTO IDAHO
AND WESTERN MONTANA.

MODELS INDICATE THAT THE CENTER OF HIGH PRESSURE WILL MOVE EAST TO
WESTERN TEXAS LATE TODAY...WHILE THE NORTHERN EXTENT OF THE RIDGE
AXIS WILL BE OVER THE UPPER MIDWEST IN RESPONSE TO THE TROUGH OFF
THE PACIFIC NW COAST MOVING THROUGH THE NORTHWESTERN QUADRANT OF THE
NATION. BY TONIGHT AND INTO THURSDAY ZONAL FLOW WILL DEVELOP ACROSS
THE DESERT SOUTHWEST AS THE HIGH BECOMES ORIENTED GENERALLY WEST TO
EAST ACROSS MEXICO INTO TEXAS. THE AFOREMENTIONED WEAK TROUGH OFF
THE BAJA COAST WILL APPROACH NORTHERN BAJA BY LATE THURSDAY/EARLY
FRIDAY AND CUT ACROSS ARIZONA LATE FRIDAY/EARLY SATURDAY. SOME
LIMITED MOISTURE TO ACCOMPANY THIS SYSTEM...SO WILL KEEP THE
ISOLATED MOUNTAIN SHOWERS IN THE FORECAST FOR SATURDAY.

AS THE WEAK SHORTWAVE TROUGH MOVES ACROSS ARIZONA EARLY SATURDAY...
AN UPSTREAM TROUGH WILL APPROACH THE WEST COAST AND THEN BECOME A
CUTOFF LOW OVER THE NORTHERN GULF OF CALIFORNIA BY LATE SUNDAY/EARLY
MONDAY BEFORE MOVING SOUTHEAST INTO MEXICO BY TUESDAY. THIS SYSTEM
COULD BRING ISOLATED SHOWERS FOR MAINLY THE MOUNTAINS DURING THE
SUNDAY TO MONDAY TIME FRAME. THEREAFTER...ANOTHER PACIFIC TROUGH
WILL MOVE INTO THE GREAT BASIN AND SOUTHERN CALIFORNIA AND SHOULD
SHUNT MOISTURE TO THE EAST FOR TUESDAY.

HIGH TEMPERATURES WILL GENERALLY BE AROUND 6 TO 8 DEGS ABOVE NORMAL
TODAY...THEN 3 TO 5 DEGS ABOVE NORMAL THEREAFTER. LOW TEMPS WILL BE
AROUND 4 TO 7 DEGS ABOVE NORMAL EACH MORNING.

&&

.AVIATION...VALID THRU 16/12Z.
SCATTERED TO BROKEN HIGH CLOUDS ABOVE 20K FT AGL MOVING INTO THE
AREA FROM THE WEST TODAY. SURFACE WIND WILL BE MAINLY LESS THAN 10
KTS WITH AN EAST TO SOUTHEAST COMPONENT THRU THIS MORNING...BECOMING
SOUTHWEST TO WEST 5-15 KNOTS THIS AFTERNOON WITH A FEW GUSTS TO NEAR
20 KTS MAINLY THIS MORNING...ESPECIALLY IN THE VICINITY OF KTUS.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...DRY CONDITIONS WILL PREVAIL THROUGH THURSDAY. A WEAK
AREA OF LOW PRESSURE WILL THEN BECOME ESTABLISHED OVER THE DESERT
SOUTHWEST BY THIS WEEKEND AND CONTINUE INTO EARLY NEXT WEEK. THERE
MAY BE ENOUGH MOISTURE TO GENERATE A FEW SHOWERS MAINLY NEAR THE
HIGHER TERRAIN EAST OF TUCSON SATURDAY THROUGH MONDAY. DRY
CONDITIONS WILL THEN PREVAIL AREA WIDE EARLY NEXT TUESDAY. 20-FOOT
WINDS WILL BE MAINLY EAST TO SOUTHEAST INTO WEDNESDAY MORNING
FOLLOWED BY NORMAL DIURNAL WIND TRENDS DURING THE LATTER PART OF
THIS WEEK.

&&

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

$$

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

MOLLERE







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