Flash Flood Warning 50, NWS Tucson, AZ

194 
WGUS75 KTWC 252046
FFSTWC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE TUCSON AZ
146 PM MST MON AUG 25 2014

AZC023-252215-
/O.CON.KTWC.FF.W.0050.000000T0000Z-140825T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SANTA CRUZ AZ-
146 PM MST MON AUG 25 2014

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 315 PM MST FOR SOUTH
CENTRAL SANTA CRUZ COUNTY...

AT 142 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE A THUNDERSTORM CAPABLE OF PRODUCING FLASH FLOODING OVER THE 
WARNED AREA.

THIS THUNDERSTORM WITH EXCESSIVE RAIN WILL OTHERWISE REMAIN OVER
MAINLY RURAL AREAS OF THE INDICATED COUNTY.

LAT...LON 3140 11083 3145 11076 3140 11073 3135 11073
      3134 11071 3132 11071 3132 11084 3133 11084

$$

937 
WGUS75 KTWC 252205
FFSTWC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE TUCSON AZ
305 PM MST MON AUG 25 2014

AZC023-252215-
/O.EXP.KTWC.FF.W.0050.000000T0000Z-140825T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SANTA CRUZ AZ-
305 PM MST MON AUG 25 2014

...THE FLASH FLOOD WARNING WILL EXPIRE AT 315 PM MST FOR SOUTH
CENTRAL SANTA CRUZ COUNTY...

LAT...LON 3140 11083 3145 11076 3140 11073 3135 11073
      3134 11071 3132 11071 3132 11084 3133 11084

$$

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TUCSON AZ
904 AM MST MON AUG 25 2014

.SYNOPSIS...A SIGNIFICANT CHANGE IN THE WEATHER PATTERN WILL TAKE
PLACE TODAY AND TUESDAY AS DEEPER MOISTURE MOVES BACK INTO ARIZONA.
THIS WILL RESULT IN SHOWERS AND THUNDERSTORMS...SOME WITH VERY HEAVY
RAINFALL...LATER TODAY AND TUESDAY. IMPROVING WEATHER CAN BE
ANTICIPATED WEDNESDAY...WITH DAYTIME TEMPERATURES REBOUNDING TO
SLIGHTLY ABOVE NORMAL READINGS BY THE WEEKEND.

&&

.UPDATED...SEE AVIATION AND FIRE WX DISCUSSIONS BELOW.

&&

.DISCUSSION...ALTO CUMULUS FIELD OVER THE CATALINA MOUNTAINS THIS
MORNING IS A SIGN OF THINGS TO COME LATER TODAY. AS ADVERTISED...THE
MOIST AIR STREAMING UP FROM THE SOUTH IS NOW INVADING SE ARIZONA.
DEW POINTS IN YUMA ARE IN THE MID 70S...WITH MID 60S IN TUCSON. 12Z
MORNING SOUNDING IN TUCSON AND YUMA SHOWED PRECIP WATER VALUES OVER
1.5 INCHES...BUT RECENT SOUNDER SATELLITE IMAGERY SUGGESTS THE 1.8
INCH AND ABOVE AIR IS NOW IN THE NORTHERN EDGE OF THE GULF OF
CALIFORNIA. LOCAL HI RES WRF MODEL RUNS...ALONG WITH THE U OF A WRF
RUNS SHOWS THE ELEVATED PRECIP WATER VALUES SPREADING ACROSS SANTA
CRUZ...PIMA AND PINAL COUNTIES STARTING AROUND 20Z...CONTINUING
THROUGH TUESDAY. SO...JUST LIKE THE MIDNIGHT SHIFT...I AM STILL
CONFIDENT IN A HEAVY RAIN EVENT IMPACTING SE ARIZONA...AND FURTHER
NORTH FOR THAT MATTER. HOWEVER...TIMING IS STILL THE KEY AND WHERE
THE GREATEST UNCERTAINTY LIES. CURRENTLY THINKING TODAY AND TONIGHT
WILL PROVIDE THE BEST SHOT FOR HEAVY RAIN FROM SAY TUCSON
SOUTH...BUT WE SHOULD SEE THAT HEAVIER PRECIP SHIELD SHIFT NORTH
TOWARD GRAHAM AND GREENLEE COUNTIES ON TUESDAY. WE ARE CONSIDERING A
FLASH FLOOD WATCH FOR TODAY AND WILL FURTHER CONSULT THE HIGHER
RESOLUTION DATA TO DETERMINE IF WE CAN FINE TUNE THE BEST TIME AND
LOCATION FOR THE WATCH.

EITHER WAY...BE AWARE THAT HEAVY RAIN AND FLASH FLOODING ARE A
CONCERN FOR THE NEXT 24 TO 48 HOURS.

JJB

&&

.AVIATION...VALID THRU 26/18Z.
AREA SPLIT BETWEEN HURRICANE MARIE TO THE SOUTH AND A DIGGING UPPER
TROUGH TO THE NORTH. THE LATER WILL KEEP PUMPING CIRRUS LEVEL CLOUDS
INTO THE AREA...WHILE THE FORMER WILL PUMP IN LOW/MID LEVEL MOISTURE
IN. ENOUGH MOISTURE IN PLACE FOR SCT -SHRA THIS AFTERNOON. POINT
SOUNDINGS SHOW LOWEST 5-8 KFT REMAINING DRY THOUGH WHICH SUPPORTS
SOME GUSTY OUTFLOW WINDS EVEN THOUGH FLOW ALOFT REMAINS WEAK. THE
GENERAL LACK OF STORM MOTION WILL HELP SATURATE THE COLUMN EARLY SO
THIS THREAT WILL LESSEN LATER IN THE PERIOD. ALSO...EXPECT DEEPER
MOISTURE TO SLOW WORK INTO THE AREA WHICH WILL CONTRIBUTE AS WELL.
THE SLOW STORM MOTION AND FAIRLY TROPICAL NATURE OF THE AIRMASS WILL
SUPPORT MVFR-IFR CONDITIONS NEAR THE STRONGER SHOWERS. HAVE REMOVED
THE TS MENTION FROM ALL TERMINALS AS TIMING AND CONFIDENCE IS TOO
LOW TO SUPPORT GIVEN THE LACK OF ELEVATED INSTABILITY.
NEVERTHELESS...ISOLATED TS DEVELOPMENT WILL BE POSSIBLE ACROSS THE
AREA BUT CAN'T PIN POINT DEVELOPMENT NEAR THE TERMINALS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...DEEPER MOISTURE WILL CONTINUE TO SETTLE IN ACROSS
AREA TODAY AS MOISTURE FROM HURRICANE MARIE SURGES NORTHWARD. THIS
AFTERNOON THERE WILL BE SOME POTENTIAL FOR GUSTY OUTFLOW WINDS AS
LOW LEVEL WILL REMAIN RELATIVELY DRY...THOUGH THIS WILL DIMINISH
LATER IN THE EVENING AS COLUMN BECOMES SATURATED. LIGHTNING ACTIVITY
CONTINUES TO LOOK FAIRLY LIMITED. STORM MOTION WILL BE FAIRLY SLOW
SO GIVEN THIS AND THE DEEP MOISTURE EXPECTED THIS LOOKS TO BE A GOOD
CHANCE FOR WETTING RAINS ACROSS THE AREA. CONFIDENCE IN WHEN THE
MOISTURE/SHOWERS WILL ERODE REMAINS LOW...BUT SHOULD SEE DRY
CONDITIONS AGAIN LATE WEDNESDAY AS THE UPPER TROUGH DIGGING ACROSS
THE WRN CONUS SLIDES THROUGH THE REGION. THIS WILL ALLOW TEMPS TO
CLIMB BACK TO NEAR NORMAL BY THE END OF THE MONTH.

&&

.PREV DISCUSSION...A BIG CHANGE IN THE WEATHER PATTERN WAS SHAPING
UP FOR THE NEXT COUPLE OF DAYS AS DEEPER MOISTURE RETURNS TO THE
REGION. LATEST MODELS CONTINUED TO SHOW 2 LARGE SCALE WEATHER
FEATURES THAT WILL BECOME A FACTOR IN BRINGING WIDESPREAD RAIN TO
SOUTHEAST ARIZONA LATER TODAY AND TUESDAY. HURRICANE MARIE
POSITIONED WELL OFF THE SOUTHERN TIP OF BAJA THIS MORNING WILL
CONTRIBUTE TO THE NORTHWARD PUSH OF MOISTURE POOLED SOUTH OF THE
INTERNATIONAL BORDER TODAY AND TUESDAY. RECENT SURFACE OBSERVATIONS
SUGGESTED THAT THIS MOISTURE INCREASE WAS ALREADY MATERIALIZING AS
DEWPOINTS HAVE CLIMBED INTO THE LOW TO MID 70S IN YUMA ALONG WITH
READINGS IN THE MID 60S BEING REPORTED IN TUCSON EARLY THIS MORNING.
THIS DEEPER MOISTURE WILL INTERACT WITH THE TAIL END OF A LOW
PRESSURE SYSTEM MOVING THROUGH NEVADA AND UTAH TONIGHT INTO EARLY
WEDNESDAY. THERE WAS A HIGH DEGREE OF CONFIDENCE THAT THE
INGREDIENTS FOR HEAVY RAINFALL AND SUBSEQUENT FLASH FLOODING WILL
COME TOGETHER DURING THE NEXT 12 TO 36 HOURS ACROSS SOUTHEAST
ARIZONA. CONFIDENCE REMAINED RATHER LOW...HOWEVER...ON THE TIMING OF
THE HEAVIEST RAINFALL AS MODEL SOLUTIONS DIFFER. SOME POINT TO
TONIGHT AND OTHERS SUGGEST TUESDAY AFTERNOON AND EVENING WILL BE THE
HEAVIEST. THAT SAID...NOT CONFIDENT ENOUGH ON THE TIMING TO JUSTIFY
POSTING A FLASH FLOOD WATCH ON THE MORNING FORECAST PACKAGE. FOR
NOW...WILL BANK ON TUESDAY AFTERNOON AND EARLY EVENING FOR BEING THE
BEST TIME FRAME FOR THE BULK OF THE HEAVY RAINFALL AREAWIDE. ALONG
WITH THE CLOUDINESS AND RAIN...COOLER DAYTIME TEMPERATURES CAN BE
ANTICIPATED. BY WEDNESDAY...THE RAPID DECREASE IN MOISTURE SHOULD
START THE DRYING TREND THROUGH THE WEEKEND. THIS DRYING TREND WILL
TRANSLATE TO A WARMING TREND AS WELL...WITH PROJECTED HIGH
TEMPERATURES REBOUNDING TO SLIGHTLY ABOVE NORMAL READINGS THIS
WEEKEND.

&&

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