Alert archive / Arizona / Flash Flood Warnings in 2009

Flash Flood Warning 16, NWS Tucson, AZ

July 20, 2009Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Jul 20, 2009, 7:36 PM MST for Pima County, Arizona. It was in force for 114 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 20, 2009, 7:36 PM MST (02:36 UTC)
Expired: Jul 20, 2009, 9:30 PM MST
In force: 114 min
Issued by: NWS Tucson, AZ
Area: Storm-based polygon
Flood severity: None

County Pima County, AZ

The radar

The Tucson radar (KEMX), 103 km from the middle of the area, began a volume at 02:38 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Tuscon, AZ (KTUS), launched 00:00Z, 2.6 hours before the alert went out and 78 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 14 J/kg
Mixed-layer CIN: -89 J/kg
Mixed-layer LCL: 2949 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: 9 m²/s²
0-3 km storm-relative helicity: 39 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WGUS55 KTWC 210236
FFWTWC
AZC019-210430-
/O.NEW.KTWC.FF.W.0016.090721T0236Z-090721T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE TUCSON AZ
736 PM MST MON JUL 20 2009

THE NATIONAL WEATHER SERVICE IN TUCSON HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL PIMA COUNTY IN SOUTH CENTRAL ARIZONA...

* UNTIL 930 PM MST

* AT 731 PM MST...NATIONAL WEATHER NATIONAL WEATHER SERVICE RADAR  
INDICATED FROM 1 TO 3 INCHES OF RAINFALL OVER THE PAST TWO HOURS IN 
AN AREA BETWEEN SELLS...SANTA ROSA RANCH AND KITT PEAK. WASHES AND 
LOW WATER CROSSINGS WILL BE FLOODED...ESPECIALLY ALONG HIGHWAY 86. 
THE SAN VICENTE WASH AND WASHES FLOWING NORTH TO SANTA ROSA RANCH 
WILL HAVE THE MOST SIGNIFICANT FLOODING.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO SANTA ROSA
  RANCH AND COMOBABI.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN HILLY TERRAIN THERE ARE HUNDREDS OF LOW WATER CROSSINGS WHICH ARE
POTENTIALLY DANGEROUS IN HEAVY RAIN. DO NOT ATTEMPT TO TRAVEL ACROSS
FLOODED ROADS. FIND ALTERNATE ROUTES. IT TAKES ONLY A FEW INCHES OF
SWIFTLY FLOWING WATER TO CARRY VEHICLES AWAY.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

DO NOT UNDERESTIMATE THE POWER OF FLOOD WATERS. ONLY A FEW INCHES OF
RAPIDLY FLOWING WATER CAN QUICKLY CARRY AWAY YOUR VEHICLE.

&&

LAT...LON 3201 11184 3211 11177 3216 11168 3211 11155
      3192 11155 3193 11174

$$

SHOEMAKER

2 follow-up statements

000 
WGUS75 KTWC 210332
FFSTWC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE TUCSON AZ
832 PM MST MON JUL 20 2009

AZC019-210430-
/O.CON.KTWC.FF.W.0016.000000T0000Z-090721T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PIMA AZ-
832 PM MST MON JUL 20 2009

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 930 PM MST FOR
CENTRAL PIMA COUNTY...

AT 829 PM MST...NATIONAL WEATHER NATIONAL WEATHER SERVICE RADAR  
INDICATED FROM 1 TO 3 INCHES OF RAINFALL OVER THE PAST TWO HOURS IN 
AN AREA BETWEEN SELLS...SANTA ROSA RANCH AND KITT PEAK. WASHES AND 
LOW WATER CROSSINGS WILL BE FLOODED...ESPECIALLY ALONG HIGHWAY 86. 
THE SAN VICENTE WASH AND WASHES FLOWING NORTH TO SANTA ROSA RANCH 
WILL HAVE THE MOST SIGNIFICANT FLOODING.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO SANTA ROSA
RANCH AND COMOBABI.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN HILLY TERRAIN THERE ARE HUNDREDS OF LOW WATER CROSSINGS WHICH ARE
POTENTIALLY DANGEROUS IN HEAVY RAIN. DO NOT ATTEMPT TO TRAVEL ACROSS
FLOODED ROADS. FIND ALTERNATE ROUTES. IT TAKES ONLY A FEW INCHES OF
SWIFTLY FLOWING WATER TO CARRY VEHICLES AWAY.

DO NOT UNDERESTIMATE THE POWER OF FLOOD WATERS. ONLY A FEW INCHES OF
RAPIDLY FLOWING WATER CAN QUICKLY CARRY AWAY YOUR VEHICLE.

&&

LAT...LON 3201 11184 3211 11177 3216 11168 3211 11155
      3192 11155 3193 11174

$$

CS

000 
WGUS75 KTWC 210421
FFSTWC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE TUCSON AZ
921 PM MST MON JUL 20 2009

AZC019-210432-
/O.EXP.KTWC.FF.W.0016.000000T0000Z-090721T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PIMA AZ-
921 PM MST MON JUL 20 2009

...THE FLASH FLOOD WARNING WILL EXPIRE AT 930 PM MST FOR CENTRAL PIMA
COUNTY...

LAT...LON 3201 11184 3211 11177 3216 11168 3211 11155
      3192 11155 3193 11174

$$

CS

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Tucson, AZ wrote its last area forecast discussion before this flash flood warning went out at Jul 20, 1:06 PM MST, 6 hours 30 minutes earlier.

Area forecast discussion, Jul 20, 1:06 PM MST, 6 hours 30 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
110 PM MST MON JULY 20 2009

.SYNOPSIS...STRONG HIGH PRESSURE ALOFT WILL BRING HOT CONDITIONS TO
SOUTHEAST ARIZONA THROUGH AT LEAST THE MIDDLE OF THE WEEK. MOISTURE
WILL ALSO BE SUFFICIENT FOR THE DAILY CYCLE OF SCATTERED MAINLY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS.

&&

.DISCUSSION...SOME CLOUDS ARE BEGINNING TO FORM OVER THE MOUNTAIN
TOPS AND HIGHER ELEVATIONS OF SOUTHEAST ARIZONA...THOUGH SCATTERED
SHOWER AND THUNDERSTORM ACTIVITY STILL LOOKING TO HOLD OFF. LOOKING
OUTSIDE THE CWA...ACTIVITY HAS STARTED IN EARNEST ALONG THE RIM.
GIVEN WEAK FLOW SEEN IN THE 12Z SOUNDING...NOT CONFIDENT THAT MUCH
OF THAT WILL MAKE ITS WAY DOWN HERE. WILL LIKELY NEED TO WAIT FOR
HOMEGROWN STORMS. STARTING TO SEE JUST A SMALL HANDFUL OF THOSE AT
THE TIME OF THIS WRITING...MAINLY ALONG THE INTERNATIONAL BORDER AND
ONE ISOLATED CELL OVER CENTRAL PIMA COUNTY. DEWPOINTS HAVE FALLEN TO
THE UPPER 40S AND THAT DRYING WILL HELP IN THE FORMATION OF GUSTY
WINDS/DOWNBURSTS FROM ANY STORMS THAT MAY DEVELOP TODAY.

NOT MUCH CHANGE IN THINKING WITH REGARDS TO FORECAST...SO FOR
DETAILS...PLEASE SEE PREV DISCUSSION SECTION BELOW.

&&

.AVIATION...EXPECT ISOLATED TO SCATTERED TSRA/SHRA THE REST OF THIS
AFTERNOON AND EVENING. THE STRONGEST TSRA WILL BE ACCOMPANIED WITH
WIND GUSTS OF 40-45 KTS. OTHERWISE...SCATTERED TO OCCASIONALLY
BROKEN CUMULOFORM CLOUDS WITH BASES 11-13K FT AGL INTO THIS EVENING.
TSRA/ SHRA TO DECREASE IN COVERAGE AFTER 04Z AND ANY CONVECTIVE
CLOUD DEBRIS TO DISSIPATE DURING THE NIGHT. SURFACE WINDS WLY/NWLY
5-15 KTS THRU 06Z THEN SLY/SELY 5-15 KTS LATE TONIGHT AND INTO
TUESDAY MORNING. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...ISOLATED TO SCATTERED THUNDERSTORMS WILL OCCUR THIS
WEEK...WITH THE BULK OF ACTIVITY DURING THE AFTERNOON AND EARLY
NIGHTTIME HOURS. GENERALLY LIGHT DIURNALLY DRIVEN SURFACE WINDS
EXCEPT STRONG AND ERRATIC WINDS NEAR THE STRONGEST THUNDERSTORMS.
ABOVE NORMAL DAYTIME TEMPERATURES TO OCCUR THIS WEEK.

&&

.PREV DISCUSSION...SOME DEBRIS CLOUDINESS TO START THE
MORNING...WHICH LOOKS MORE IMPRESSIVE ON SATELLITE THAN IT DOES OUT
THE WINDOW. TRENDS HAVE IT THINNING...SO THAT IS NOT EXPECTED TO
INTERFERE WITH DEVELOPMENT TODAY. MORE ON THAT LATER. DEWPOINTS AT
AREA ASOS STATIONS WERE MOSTLY IN THE MID 50S...WITH THE EXCEPTION
OF KDUG JUST SHY OF 50. TAKING A LOOK AT THE 12Z SOUNDING...A LITTLE
MORE WET BUT SLIGHTLY MORE STABLE THAN 24 HOURS AGO WITH BETTER
DIRECTIONAL SHEER...THOUGH STILL FAIRLY WEAK FLOW. ALSO OF NOTE ON
THE SATELLITE...ALREADY GETTING SOME ACTIVITY SOUTH OF THE
BORDER...WAY SOUTH...AS WELL AS SOME LINGERING ACTIVITY SOUTHEAST OF
PRESCOTT.

TAKING WHAT IS ALREADY HAPPENING INTO ACCOUNT...12Z NAM SHOWS A
COUPLE OF DISTURBANCES THAT WILL IMPACT SE AZ TODAY...ONE OVER
SOUTHERN NV AT THIS TIME MOVING INTO NORTHERN AZ...THE OTHER PUSHING
INTO SE AZ FROM THE SOUTH. SHOULD THIS HOLD...AND THE AFOREMENTIONED
ACTIVITY HINTS STRONGLY IN FAVOR OF THIS...SHOULD SEE A SIMILAR DAY
TODAY AS WHAT WAS SEEN YESTERDAY...WITH ACTIVITY FLARING UP BOTH ON
THE RIM AND ALONG THE INTERNATIONAL BORDER...EACH SPREADING INTO SE
AZ. WITH THE WEAK FLOW...NOT EXPECTING ANY STORMS THAT DEVELOP TO
MOVE ALL THAT FAST. MORE MOISTURE AT THE SURFACE...SHOULD IT
HOLD...MAY HELP MITIGATE A WIND THREAT FROM STORMS THAT
DEVELOP...BUT GIVEN THAT THERE IS NOT MUCH DIFFERENCE IN CONDITIONS
VERSUS 24 HOURS AGO...DO NOT FEEL COMFORTABLE RULING THAT OUT AT
THIS TIME.

MOVING OUT OF THE VERY SHORT TERM...THE HIGH WOBBLES WESTWARD AND
THIS WOBBLING WILL MAKE TUES AND WEDS LOOK SIMILAR TO TODAY
ACCORDING TO THE MODELS. MOVING BEYOND MID WEEK...MID TO LONG RANGE
MODELS SHOW THE RIDGE INTENSIFYING WITH THE HIGH CENTER NORTH OF THE
FOUR CORNERS. THIS WOULD TAKE IT OUT OF THE PRIME REAL ESTATE FOR
BRINGING MOISTURE INTO SE AZ WHICH WOULD VALIDATE THE INHERITED LOW
RANGE MONSOON POPS. WILL WAIT AND SEE WHAT THE 12Z RUN OFFERS...BUT
CAN SEE NO REASON TO ARGUE.

ONE LAST THING TO MENTION...WITH THE RIDGE REMAINING IN PLACE...AND
EVEN INTENSIFYING...AFTERNOON HIGH TEMPERATURES ARE EXPECTED TO
REMAIN ABOVE CLIMATOLOGICAL NORMALS AND SHOW LITTLE VARIANCE FROM
DAY TO DAY. THIS WOULD KEEP THE TUCSON METRO OVER THE CENTURY MARK
FOR THE ENTIRE FORECAST PERIOD...PUSHING THE WESTERN DESERTS TO
CLOSER TO 110 AND EASTERN VALLEYS TO THE UPPER 90S.

INHERITED FORECAST APPEARS TO BE ON TRACK. EXPECT TO MAKE SOME
SLIGHT TWEAKS TO TAKE INTO ACCOUNT CURRENT OBS AND NEWEST MODEL
DATA...BUT OTHERWISE NO SIGNIFICANT CHANGES EXPECTED.

&&

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

WEATHER.GOV/TUCSON

Hazardous weather outlook, Jul 20, 8:57 AM MST, 10 hours 39 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
857 AM MST MON JUL 20 2009

AZZ019-030-034-035-211200-
NORTHERN GREENLEE COUNTY-UPPER GILA RIVER VALLEY-
SANTA CRUZ COUNTY-COCHISE COUNTY-
857 AM MST MON JUL 20 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST
ARIZONA.

.DAY ONE...TODAY AND TONIGHT

ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP THIS AFTERNOON AND CONTINUE INTO THIS EVENING. THE
STRONGEST STORMS MAY PRODUCE BRIEF HEAVY RAIN AND WIND GUSTS UP TO
45 MPH. THE BULK OF THE ACTIVITY IS FORECAST TO END BY AROUND
MIDNIGHT TONIGHT.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THE DAILY CYCLE OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
IS EXPECTED TO CONTINUE THROUGH SUNDAY...WITH ACTIVITY EXPECTED TO
DEVELOP DURING THE AFTERNOON AND CONTINUE INTO THE EVENING HOURS.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

AZZ029-031>033-211200-
SOUTHEAST PINAL COUNTY-WESTERN PIMA COUNTY-TOHONO OODHAM NATION-
TUCSON METRO/MARANA/GREEN VALLEY-
857 AM MST MON JUL 20 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
ARIZONA AND SOUTHEAST ARIZONA.

.DAY ONE...TODAY AND TONIGHT

ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP ACROSS THE AREA THIS AFTERNOON INTO THIS EVENING. THE
STRONGEST STORMS MAY PRODUCE BRIEF PERIODS OF HEAVY RAIN...WIND
GUSTS UP TO 45 MPH AND REDUCED VISIBILITIES DUE TO BLOWING DUST.
THE MAJORITY OF ACTIVITY IS EXPECTED TO END BY MIDNIGHT TONIGHT.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THE DAILY CYCLE OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
IS EXPECTED TO CONTINUE THROUGH WEDNESDAY BEFORE BECOMING MORE
ISOLATED FOR THE REMAINDER OF THE WEEK. ACTIVITY IS EXPECTED TO
DEVELOP DURING THE AFTERNOON AND CONTINUE INTO THE EVENING HOURS.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

WEATHER.GOV/TUCSON

In the hours before

Local storm report, Jul 20, 5:30 PM MST, 2 hours 6 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON AZ
530 PM MST MON JUL 20 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0408 PM     TSTM WND DMG     7 W THREE POINTS        32.07N 111.40W
07/20/2009                   PIMA               AZ   BROADCAST MEDIA

            20 POWER POLES BLOWN DOWN ON STATE HIGHWAY 86 WEST OF
            THREE POINTS.

&&

JD

Local storm report, Jul 20, 7:11 PM MST, 25 minutes before

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE TUCSON AZ
711 PM MST MON JUL 20 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0247 PM     TSTM WND DMG     W RYAN FIELD            32.14N 111.17W
07/20/2009                   PIMA               AZ   LAW ENFORCEMENT

            20 POWER POLES BLOWN DOWN NEAR VALENCIA AND AJO WAY.

&&

CSHOEMAK

The office that day

Everything else NWS Tucson, AZ issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 20, 5:19 PM MST	Severe Thunderstorm Warning	TWC	Pima	41 min
Jul 20, 6:29 PM MST	Severe Thunderstorm Warning	TWC	Pima	46 min
Jul 20, 6:56 PM MST	Areal Flood Advisory	TWC	Pima	4 hr

Nearby

Flash Flood Warnings in Arizona, 2009 Every flash flood warning in 2009

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.