Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 162127
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
230 PM MST TUE SEP 16 2014

.SYNOPSIS...PERIODS OF SHOWERS AND THUNDERSTORMS CAN BE EXPECTED
THROUGH TONIGHT INTO EARLY WEDNESDAY...WITH HEAVY RAINFALL
POSSIBLE.  THE MOST WIDESPREAD AND HEAVIEST RAIN IS EXPECTED
WEDNESDAY AFTERNOON INTO THURSDAY WITH POTENTIAL FLOODING AND FLASH
FLOOD ISSUES.  THEREAFTER...LINGERING TROPICAL MOISTURE WILL KEEP
SCATTERED SHOWERS AND THUNDERSTORMS IN THE FORECAST FRIDAY THROUGH
THE WEEKEND.

&&

.DISCUSSION...AREAS OF LIGHT TO MODERATE SHOWERS CONTINUE TO MOVE
NORTH ACROSS THE REGION THIS AFTERNOON AS MOISTURE CONTINUES TO
SWEEP NORTH.  LIMITED SUNSHINE AND LACK OF DYNAMICS BETWEEN BANDS
HAS MELLOWED THE CONVECTION THUS FAR.  HOWEVER A BAND JUST TO THE
SOUTH IS HEADED OUR WAY AND WILL LIKELY GENERATE STEADIER
PRECIPITATION ACROSS THE AREA AS IT MOVES NORTH AND LIKELY AN
INCREASE IN INTENSITY.  HIRES MODELS SUGGEST SOME SIGNIFICANT CELLS
DEVELOPING LATER THIS EVENING AND OVERNIGHT ACROSS SOUTHERN AREAS AS
THIS BAND PASSES AND ODILE CONTINUES ITS SLOW MARCH NORTH.  WITH
THAT IN MIND HAVE MOVED UP THE TIME OF THE FLASH FLOOD WATCH FOR
SANTA CRUZ AND SOUTHERN PIMA COUNTIES BY 6 HOURS TO START THIS
EVENING JUST AS A PRECAUTION AS THERE IS POTENTIAL FOR LOCALLY HEAVY
RAINS TONIGHT FOR SOME LOCATIONS.  THAT SAID...THE MAIN TIME OF
CONCERN REMAINS LATER WEDNESDAY INTO EARLY THURSDAY.

TROPICAL STORM ODILE IS EXPECTED TO MAKE LANDFALL OVER NORTHWEST
SONORA MEXICO WEDNESDAY MORNING THEN MOVE NORTHEAST INTO CENTRAL
ARIZONA THROUGH THURSDAY MORNING WITH THE MAIN CONCERN HEAVY RAIN.
PERIODS OF HEAVY RAIN ARE ANTICIPATED NEAR AND TO THE RIGHT OF THE
TRACK OF THE SYSTEM WITH A FAIRLY SHARP CUTOFF TO THE WEST...SO THE
TRACK THAT ODILE DECIDES TO TAKE IS CRITICAL TO WHERE THE HEAVIEST
RAIN MAY FALL.

THE CURRENT THINKING IS THE STORM WILL PASS BY...NEAR OR JUST WEST
OF TUCSON WITH THE CORE OF THE HEAVIER RAIN IN THAT AREA AND TO THE
EAST...BUT STAY CURRENT WITH THE LATEST UPDATES AS THIS IS A VERY
DYNAMIC SITUATION.  AS IS NORMALLY THE CASE AND EXPECTED THIS TIME
AS WELL...RAINFALL AMOUNTS WILL BE HIGHLY VARIABLE ACROSS THE AREA
EVEN OVER SHORT DISTANCES.  THE POTENTIAL EXISTS FOR 3 TO 5 INCHES
OF RAIN THROUGH THURSDAY OVER SIGNIFICANT AREAS WITH LOCALLY HIGHER
AMOUNTS NOT OUT OF THE QUESTION.  OF NOTE IS THAT A SIGNIFICANT
PORTION OF THE HEAVY RAIN IS EXPECTED TO OCCUR WEDNESDAY NIGHT WITH
CREEK AND STREAM RISES OCCURRING DURING NIGHTTIME HOURS.

WITH THAT PATH IN MIND...THE AREAS OF BIGGEST THREAT FOR FLASH FLOOD
AND FLOOD ACTIVITY WOULD BE IN SANTA CRUZ...SOUTHERN AND EASTERN
PIMA...COCHISE...SOUTHERN GRAHAM...AND GREENLEE COUNTIES AND FLASH
FLOOD WATCHES ARE IN AFFECT.  PLEASE SEE THE HYDROLOGY SECTION
BELOW FOR MORE DETAILS ON RIVER AND CREEK FLOODING POTENTIAL.

DEPENDING ON HOW FAST THE REMAINS OF ODILE MOVES...THE STEADIER RAIN
WILL TAPER OFF DURING THE DAY THURSDAY FROM WEST TO EAST WITH
SCATTERED SHOWERS BEING LEFT IN ITS WAKE.  BY FRIDAY...A SHORT WAVE
RIDGE BUILDS OVER THE AREA AS WHATS LEFT OF ODILE MOVES INTO
NORTHERN TEXAS.  EVEN WITH THE RIDGE...A FAIR AMOUNT OF MOISTURE
REMAINS BEHIND FOR SCATTERED SHOWERS AND THUNDERSTORMS TO REMAIN IN
THE FORECAST.

THEN FOR THE WEEKEND AN UPPER LOW OFF THE SOUTHERN CALIFORNIA COAST
WILL SLOWLY LIFT NE THROUGH MONDAY MAINTAINING A MOIST SOUTHERLY
FLOW OVER THE REGION.  THUS WE WILL LIKELY HAVE SCATTERED CONVECTION
THROUGH THE WEEKEND WITH AN AFTERNOON AND EVENING FOCUS.  BEYOND
THAT THERE IS NO SIGNIFICANT DRYING TREND UNTIL WEDNESDAY WITH
LINGERING CONVECTION THROUGH AT LEAST THEN.  CERNIGLIA

&&

.HYDROLOGY...TROPICAL STORM ODILE IS EXPECTED TO GENERATE HEAVY
RAINFALL ACROSS MUCH OF SOUTHEAST ARIZONA THROUGH THURSDAY WITH
STORM TOTAL RAINFALL AMOUNTS RANGING FROM 1.5 TO 6 INCHES POSSIBLE.
FLOODING ON CREEKS AND WASHES IS POSSIBLE WEDNESDAY THROUGH THURSDAY
WITH MAIN STEM RIVER FLOODING POSSIBLE THROUGH THE WEEKEND.  THE
MAIN STEM RIVERS OF CONCERN ARE THE GILA...SAN PEDRO AND SANTA
CRUZ.  SOME OF THE SMALLER CREEKS OF CONCERN INCLUDE BUT NOT LIMITED
TO THE SABINO...THE BRAWLEY AND THE NOGALES WASH.  FOR INDIVIDUAL
RIVER FORECASTS PLEASE REFER TO THE COLORADO BASIN RIVER FORECAST
CENTER WED SITE AT WWW.CBRFC.NOAA.GOV  CERNIGLIA/BOYLE

&&

.AVIATION...VALID THRU 18/00Z
ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
CONTINUE TO INCREASE THROUGH THIS EVENING...WITH WIDESPREAD ACTIVITY
EXPECTED BY MIDDAY WEDNESDAY AND CONTINUING INTO THURSDAY. AREAS OF
CIGS NEAR 5K FT AGL DEVELOPING ACROSS SOUTHERN PARTS OF THE REGION
WITH MULTIPLE LAYERS ABOVE...WITH MVFR CONDITIONS POSSIBLE AS THE
SYSTEM MAKES ITS WAY THROUGH SOUTHERN ARIZONA. SFC WINDS WILL
GENERALLY BE LESS THAN 10 KTS...EXCEPT STRONGER SOUTHEAST WINDS
DEVELOPING ALONG THE INTERNATIONAL BORDER NEAR NOGALES WHERE WINDS
OF 15 TO 20 MPH WITH STRONGER GUSTS WILL BE POSSIBLE...ESPECIALLY IN
THE VICINITY OF STRONGER SHOWERS AND/OR THUNDERSTORMS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...INCREASING TROPICAL MOISTURE WITH WIDESPREAD SHOWER
AND THUNDERSTORM ACTIVITY DEVELOPING...ESPECIALLY LATE TONIGHT
THROUGH THURSDAY. THERE IS A GOOD THREAT OF FLOODING ISSUES LATE
WEDNESDAY...WEDNESDAY NIGHT AND THURSDAY. EVEN AFTER ODILE WE EXPECT
TO KEEP ENOUGH MOISTURE AROUND FOR A CHANCE OF SHOWERS AND
THUNDERSTORMS FRIDAY INTO THE WEEKEND.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
  FLASH FLOOD WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY
  AFTERNOON FOR AZZ501-505-506-509-510.

  FLASH FLOOD WATCH THROUGH THURSDAY AFTERNOON FOR
  AZZ507-508-512-513.

  FLASH FLOOD WATCH FROM THIS EVENING THROUGH THURSDAY
  AFTERNOON FOR AZZ502>504-511-514-515.

&&

$$

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