Arizona, 2015Heavy Rain in Arizona, May 4, 2015
May 4, 2015 · NWS PSR · 1 event in 1 county or zone
During the early morning hours on May 4th, scattered showers and thunderstorms developed across the central Arizona deserts, and they developed they produced locally moderate to heavy rain. Most of the rainfall totals were less than one half inch, but a few of the stronger thunderstorms produced locally heavier amounts of rain which resulted in minor street flooding across portions of the…
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- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
During the early morning hours on May 4th, scattered showers and thunderstorms developed across the central Arizona deserts, and they developed they produced locally moderate to heavy rain. Most of the rainfall totals were less than one half inch, but a few of the stronger thunderstorms produced locally heavier amounts of rain which resulted in minor street flooding across portions of the greater Phoenix metropolitan area. No flash flooding was reported however. The local street flooding created disruptions to the start of the morning rush hour in Phoenix.
What forecasters said that day
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Phoenix, AZ wrote its last area forecast discussion before the first event at May 3, 7:27 PM MST, 5 hours 33 minutes earlier.
Area forecast discussion, May 3, 7:27 PM MST, 5 hours 33 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
727 PM MST SUN MAY 3 2015
.SYNOPSIS...A SERIES OF PACIFIC WEATHER DISTURBANCES IS FORECAST TO
MOVE INTO THE REGION...RESULTING IN A COOLING TREND. A LARGE AND
COLDER DISTURBANCE IS FORECAST TO MOVE INTO THE REGION EARLY MONDAY
MORNING THROUGH TUESDAY...FOR AN INCREASING CHANCE OF SHOWERS AND
THUNDERSTORMS...MAINLY ACROSS ARIZONA. CLEARING IS EXPECTED LATE
TUESDAY THROUGH THE REMAINDER OF THE WEEK AND NEXT WEEKEND...HOWEVER
WITH SEVERAL PACIFIC WEATHER SYSTEMS FORECAST TO MOVE INTO THE
WESTERN STATES NORTH OF ARIZONA THIS WEEK...BELOW NORMAL TEMPERATURES
ARE EXPECTED THE NEXT SEVEN DAYS.
&&
.DISCUSSION...
ISOLATED SHOWERS CONTINUE TO PERCOLATE ACROSS PORTIONS OF WESTERN
MARICOPA COUNTY AND CENTRAL PINAL COUNTY. UNLIKE YESTERDAY...DUST
PROBLEMS HAVE BEEN FEW AND FAR BETWEEN THIS EVENING AS STORMS HAVE
STRUGGLED TO MAINTAIN CORES ABOVE 20-25KFT. NONETHELESS A FEW SPOTS
SOUTHWEST OF THE METRO MANAGED TO SQUEEZE OUT A FEW HUNDREDTHS OF AN
INCH OF RAINFALL SINCE 00Z.
TAKING A LOOK AT INCOMING 00Z NAM...21Z SREF...AND THE LAST 5-6 RUNS
OF THE HRRR...ALL GUIDANCE IS POINTING TOWARD THE DEVELOPMENT OF
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS AFTER MIDNIGHT WITH
MEASURABLE PRECIP ACROSS THE PHOENIX AREA BEFORE DAYBREAK.
APPROXIMATELY HALF OF THE 21Z SREF MEMBERS INDICATE MEASURABLE PRECIP
AT KPHX AROUND 09Z AND I FELT IT PRUDENT TO ADJUST THE FORECAST IN
THAT DIRECTION. MAKING SOME UPWARD ADJUSTMENTS TO THE POPS AFTER 06Z
AND ACCELERATING THE ONSET OF RAIN ACROSS THE AREA. WHILE AMOUNTS
WILL BE LIGHT /FEW HUNDREDTHS/...IT SHOULD NONETHELESS MAKE FOR A
DAMP MONDAY MORNING COMMUTE.
THE REMAINDER OF THE INHERITED FORECAST GRIDS ARE IN GOOD
SHAPE...WILL MAKE MINOR ADJUSTMENTS TO TEMPS/DEWPOINTS/WINDS BASED ON
OBSERVATIONAL TRENDS BUT NOTHING SIGNIFICANT.
&&
.PREVIOUS DISCUSSION...
MONDAY THROUGH TUESDAY...
FOR MONDAY AND TUESDAY A MAJOR COOL PACIFIC TROF IS STILL ON TRACK
TO MOVE FORECAST TO MOVE INTO SOUTHERN CA TONIGHT THEN INTO AZ MONDAY
MORNING THROUGH TUESDAY MORNING. THIS IS A MUCH COLDER TROF WITH WITH
SOMEWHAT STRONG UPPER LEVEL DYNAMICS...AND...WITH INCREASED BOUNDARY
LAYER MOISTURE WILL LEAD TO A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS AREA-WIDE. SINCE IT WILL BE A SLOW EASTWARD MOVING
TROF...THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO
EARLY TUESDAY.
WEDNESDAY...PARTLY CLOUDY SKIES ARE EXPECTED WITH NO PRECIP AS A
MINOR SHORTWAVE RIDGE MOVES QUICKLY THROUGH THE REGION.
THURSDAY THROUGH SATURDAY...ANOTHER COOL TROF IS FORECAST TO MOVE
INTO THE WESTERN REGION MAINLY NORTH OF OUR FORECAST AREA. PRECIP
CHANCES SHOULD MOSTLY BE CONFINED TO OUR SOUTHEAST CA JOSHUA TREE
ZONE 30. HOWEVER...STRONG 500-300 MB HEIGHT FALLS OVER THE MOHAVE
DESERT OF CA FRIDAY SUGGESTS VERY STRONG GUSTY WEST WINDS ACROSS
MUCH OF SOUTHEAST CA AND THE COLORADO RIVER VALLEY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
SHOWERS HAVE AVOIDED THE PHOENIX TERMINALS SO FAR THIS EVENING...BUT
WILL BECOME MORE SCATTERED IN NATURE AROUND 09Z WITH SEVERAL HOURS OF
-SHRA EXPECTED AT ALL 3 PHOENIX TAF SITES. EXPECTING CIGS TO LOWER TO
AROUND 4-6KFT /WILL VARY BASED ON INTENSITY OF PASSING SHOWERS/
THROUGH APPROX 15Z...THEN IMPROVE FOR A BIT INTO THE EARLY AFTERNOON
HOURS. EXPECTING ANOTHER ROUND OF ISOLATED/SCATTERED LATE-DAY -SHRA
AFTER 22Z BUT AT THIS POINT WILL ONLY MENTION VCSH AS CONFIDENCE IN
AREAL COVERAGE IS LOW. AS FOR WINDS...SHOULD SEE A PERSISTENT
WESTERLY DIRECTION AT KPHX OVERNIGHT ALTHOUGH KIWA MAY TRY AND TAKE
ITS USUAL TURN OUT OF THE SOUTHEAST AFTER MIDNIGHT.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NOT EXPECTING ANY SHOWERS TO IMPACT EITHER KIPL OR KBLH. MOST LIKELY
IMPACT FROM THE APPROACHING TROUGH WILL BE IN THE FORM OF BLOWOFF
CIRRUS AND BREEZY AFTERNOON WINDS. OTHERWISE...WEATHER IMPACTS SHOULD
BE CONFINED TO AREAS EAST OF THE CO RIVER.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
DRY WEATHER...AND SLIGHTLY WARMER TEMPERATURES TO RETURN WEDNESDAY
AS WEAK HIGH PRESSURE PASSES OVER THE REGION. GUSTY WINDS AND COOLER
TEMPERATURES TO PREVAIL ACROSS THE REGION FROM THURSDAY ONWARD INTO
SATURDAY AS ANOTHER PACIFIC STORM SYSTEM MOVES ACROSS THE GREAT
BASIN. FIRE DANGER LEVELS WILL LIKELY BE ELEVATED DURING THIS PERIOD
AS AFTERNOON HUMIDITIES FALL INTO THE TEENS. SLIGHTLY WARMER
TEMPERATURES AND LESS WIND CAN BE EXPECTED ON SATURDAY AS THE
AFOREMENTIONED PACIFIC STORM SYSTEM BEGINS TO MOVE OFF TO THE EAST.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/VASQUEZ
AVIATION...LEINS
FIRE WEATHER...NOLTE/PERCHA
In the hours before
Local storm report, May 4, 12:52 AM MST, 8 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
1252 AM MST MON MAY 04 2015
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1250 AM HEAVY RAIN 4 S LAVEEN 33.36N 112.14W
05/04/2015 E0.25 INCH MARICOPA AZ CO-OP OBSERVER
&&
EVENT NUMBER PSR1500033
MPHeavy Rain, Maricopa
- When
- May 4, 1:00 AM MST to 4:30 AM MST
- Where
- Maricopa County, 2.97 mi ESE of Laveen
- Reported by
- Trained Spotter
- Coordinates
- 33.360, -112.120
Scattered showers and thunderstorms developed shortly after midnight across the south central Arizona deserts on May 4th, and they produced locally moderate to heavy rainfall over the greater Phoenix metropolitan area. Around 0112MST, a coop observer near Chandler Fashion Square Mall estimated one half of an inch of rain fell since midnight. The thunderstorms that produced the heavy rain also generated frequent lighting and winds over 40 mph. Showers persisted through the early morning and at 0413MST, a trained spotter 3 miles northwest of South Mountain Park reported minor street flooding at the intersection of 27th Avenue and Dobbins Road. The local street flooding created disruptions to the start of the morning rush hour in Phoenix.
- Heavy Rain
- Rainfall totals unusual for the place and season that did not produce a flood.
After NWS Directive 10-1605, the rules offices file Storm Data by.
- Flash Flood and Flooding in Texas, May 4 to 5, 20151 injured · $311 million · 6 events
- Hurricane in Guam, May 4 to 7, 20151 death · $100,000 · 1 event
- Flash Flood and Hail in Iowa, May 4, 20151 death · 2 injured · 0.88 in hail · 3 events
- Flash Flood and Hail in New Mexico, May 4 to 5, 2015$3.0 million · 1.5 in hail · 11 events
- Tornadoes and Flash Flood in Kansas, May 4, 2015EF1 · 15 events
- Flash Flooding and Hail in Texas, May 4 to 5, 2015$17,000 · 2.5 in hail · 24 events
- Flash Flood in Colorado, May 4, 2015$20,000 · 1 event
- Flash Flooding and Hail in Kansas, May 4, 20151 in hail · 13 events
- Hail in Indiana, May 4, 20151.75 in hail · 8 events
- Flash Flooding and Flood in Missouri, May 4, 20151 in hail · 7 events
- Flash Flood and Hail in Illinois, May 4, 20151 in hail · 4 events
- Flooding in Kansas, May 4 to 5, 2015$800 · 4 events
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 566148.