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000
FXUS65 KTWC 140933
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
235 AM MST TUE MAY 14 2013

.SYNOPSIS...A WEAK LOW IN NORTHERN MEXICO WILL PUSH NORTHEAST
THROUGH THE AREA TODAY...WITH A CHANCE OF MAINLY MOUNTAIN
THUNDERSTORMS THIS AFTERNOON AND EVENING. OTHERWISE...TEMPERATURES
WILL CONTINUE TO HEAT UP DURING THE WORK WEEK WITH HIGHS NEAR 100
DEGREES IN THE LOWER DESERT LOCATIONS AND 90S ELSEWHERE. A STRONGER
SYSTEM WILL MOVE NORTH OF THE REGION THIS COMING WEEKEND...RESULTING
IN SEVERAL DEGREES OF COOLING AND BREEZY CONDITIONS.

&&

.DISCUSSION...SOME MID CLOUD ENHANCEMENT THIS MORNING ON THE
NORTHERN PERIPHERY OF THE WEAKENING LOW IN NORTHWEST MEXICO. A FEW
SPRINKLES REACHING THE GROUND UNDER MOSTLY VIRGA EARLY THIS MORNING.
SOME BOUNDARY LAYER MOISTURE INCREASE UNDER THE MID LEVEL
MOISTURE...AS THE LOW SHEARS INTO NEW MEXICO ON IT`S WAY TO HIGHER
LATITUDES OVER THE NEXT 12 TO 24 HOURS. WE SHOULD MANAGE ENOUGH
INSTABILITY FOR UNSEASONABLE MODERATE CONVECTIVE DEVELOPMENT OVER
THE MOUNTAINS AS REFLECTED BY LATEST HRRR AND NAMDNG5 TRENDS. LATEST
RAPID REFRESH AND PREVIOUS UOFAZ WRF OUTPUT SUGGEST DEVELOPING 250
TO 400 VALLEY CAPE THIS AFTERNOON. COMBINED WITH A LESS FAVORABLE
FLOW WE STILL DON`T EXPECT TO BE ABLE TO SUPPORT MUCH CONVECTION IN
MOST VALLEY LOCATIONS...HOWEVER SOME ORGANIZED OUTFLOW FROM
COLLAPSING STORMS AS THEY TRY TO PUSH INTO VALLEYS EXPECTED AND FEW
HUNDREDTHS HERE AND THERE NOT OUT OF THE QUESTION.

THE RIDGE CLEANS UP A BIT AS THIS WEAKNESS KICKS WELL NORTHEAST
TONIGHT...BUT LOSES GEOMETRY AS THE AXIS SHIFTS EAST OF US THURSDAY
WITH A DEVELOPING SYSTEM NEAR THE PACIFIC NORTHWEST. AFTER A PAUSE
IN THE HEATING TREND TODAY...WE`LL HAVE TIME TO JUMP BACK INTO
HOTTER TEMPERATURES WEDNESDAY AND THURSDAY BUT STILL HAVING A HARD
TIME JUSTIFYING THE FIRST 100 AT TIA...98 OR 99 IS ABOUT ALL WE CAN
CURRENTLY SQUEEZE OUT OF THE FORECASTED THICKNESS AND HEIGHT TRENDS.

TROUGH PUSHING THROUGH THE REGION FRIDAY INTO THE WEEKEND. AS ONE
MIGHT EXPECT FOR THE SECOND HALF OF MAY...DYNAMICS AND BEST MOISTURE
WELL NORTH OF OUR CWA BUT WE CAN EXPECT A MODEST COOLING TREND AND
GUSTY WINDS OUT OF THE SYSTEM.

WEAKENING RIDGE PHASING ACROSS THE AREA EARLY NEXT WEEK COULD BRING
THE FIRST 100 FOR TIA MONDAY OR TUESDAY IF WE CAN`T MANAGE IT THIS
WEEK.

&&

.AVIATION...SKC-SCT 12KFT AGL LCL BKN 10KFT AGL WITH ISOLD -SHRA.
FROM 14/20Z THRU 15/04Z SCT-BKN 12KFT WDLY SCTD -SHRA/TS BKN 8KFT
AGL...MAINLY E AND S OF KTUS. AFT 15/04Z...FEW-SCT LCLY BKN 10KFT
AGL. SFC WIND E-S 5-10 KTS WITH LCL GUSTS TO 18 KTS...FROM 14/19Z
THRU 15/04Z SFC WND W-S 8-15 KTS WITH OCNL GUSTS 18-24 KTS...HIGHER
GUSTS NR SHRA/TS E AND S OF KTUS...AFT 15/04Z WIND TERRAIN DRIVEN
LESS THAN 10 KTS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...A WEAK UPPER LOW OVER NORTHERN MEXICO WILL MOVE
NORTHEAST TODAY INTO THIS EVENING. ENOUGH MOISTURE IS AROUND FOR THE
DEVELOPMENT OF ISOLATED SHOWERS...POSSIBLY A THUNDERSTORM...FROM
TUCSON EAST AND SOUTH. WEAK RIDGE OF HIGH PRESSURE OVER THE AREA
WEDNESDAY AND THURSDAY BEFORE AN UPPER LEVEL TROUGH MOVES THROUGH
THE INTERMOUNTAIN WEST FRIDAY AND SATURDAY BRINGING BREEZY TO
LOCALLY WINDY CONDITIONS TO THE REGION.

&&

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

&&

$$

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