FXUS65 KTWC 300351
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
851 PM MST THU JUL 29 2010

.SYNOPSIS...A SERIES OF WEATHER DISTURBANCES ACTING ON DEEP MOISTURE 
IN PLACE OVER SOUTHEAST ARIZONA WILL BRING INCREASED THUNDERSTORM 
CHANCES THROUGH THIS WEEKEND. VERY HEAVY RAIN...FLOODING AND 
ISOLATED MICROBURSTS WILL BE THE MAIN THREATS.

&&

.DISCUSSION...SCATTERED SHOWERS AND A FEW THUNDERSTORMS CONTINUED 
ACROSS PARTS OF GRAHAM...COCHISE AND EASTERN SANTA CRUZ COUNTIES. 
THIS ACTIVITY WAS SLOWLY MOVING WESTWARD AND MAY MOVE INTO PARTS OF 
EASTERN PIMA AND PINAL COUNTIES YET TONIGHT. OVERALL...EXPECT 
ACTIVITY TO DIMINISH AFTER MIDNIGHT BUT CANNOT RULE OUT A FEW 
SHOWERS OR THUNDERSTORMS THROUGH AT LEAST 12Z FRI. OTHERWISE...STILL 
LOOKING AT FAVORABLE CONDITIONS FOR ELEVATED CHANCES OF SHOWERS AND 
THUNDERSTORMS FRIDAY AND OVER THE WEEKEND. PLEASE REFER TO THE 
PREVIOUS DISCUSSION SECTION BELOW FOR MORE DETAILS. 

&&

.AVIATION...SCT-LCLY TSRA WILL HAVE SCT-BKN BASES AROUND 5-7KFT WITH 
CIGS/VSBYS REACHING THE MVFR CATEGORY AT TIMES IN TSRA WITH 
MOUNTAINS OBSCURATIONS PREVALENT THROUGH 10Z FRI. AFT 10Z FRI EXPECT 
ISOLD SHOWERS WITH SCT-BKN BASES OF 7-9KFT AGL ALTHOUGH LOWER CLOUDS 
AND FOG OBSCURING MOUNTAINS WILL BE POSSIBLE FROM 10Z-15Z. SFC WINDS 
WILL BE LESS THAN 10 KTS...EXPECT GUSTS NEAR 40 KTS NEAR THE 
STRONGER THUNDERSTORMS. AVIATION DISCUSSION NOT UPDATED FOR TAF 
AMENDMENTS.

&&

.FIRE WEATHER...NO FIRE WEATHER CONCERNS AT THIS TIME.  

&&

.PREV DISCUSSION...UPPER CIRCULATION MOVING W FROM NM WEAKENS 
FURTHER WHILE THE ONE OVER BAJA NUDGES SLIGHTLY NORTHWARD. THIS MAY 
ACTUALLY CREATE A MORE CONDUCIVE ENVIRONMENT TO LIFT MOISTURE 
REMAINING IN PLACE.  HAVE MAINTAINED OR SLIGHTLY RAISED POPS.  
LATEST SREF CONTINUES TO POINT TO MORE WIDESPREAD HEAVIER RAIN SO 
FLASH FLOOD WATCH MAY END UP MORE SUITED FOR FRIDAY AND/OR SATURDAY 
THAN TODAY.

MODELS LOOK MORE ACTIVE SUN AND MON THAN DURING PREVIOUS RUNS BUT 
FOCUS MAY NEVERTHELESS BE SHIFTING INTO NWD CWFA AND NORTHWARD.  DID 
RAISE SOME OF THE OVERNIGHT POPS SAT NGT AND SUN NGT THOUGH DUE TO 
CONTINUED DEEP MOISTURE AND DISTURBANCES IN THE AREA. DID NOT MAKE 
MUCH IN THE WAY OF CHANGES TO LATER PERIODS AT THIS TIME. MODELS 
SUGGEST THAT TUES/WED COULD BE LESS ACTIVITY THAN OF LATE BUT THAT 
COULD CERTAINLY CHANGE.

&&

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

$$

WEATHER.GOV/TUCSON