Alert archive / California / Severe Thunderstorm Warnings in 1999
Severe Thunderstorm Warning 33, NWS Phoenix, AZ
NWS Phoenix, AZ issued this severe thunderstorm warning at Jul 28, 1999, 4:44 PM PDT for Imperial County, California. It was in force for 61 min. 1 report came from inside the area while it was in force.
The area
The counties it named, with what was reported inside it.
The facts
- Issued
- Jul 28, 1999, 4:44 PM PDT (23:44 UTC)
- Expired
- Jul 28, 1999, 5:45 PM PDT
- In force
- 61 min
- Issued by
- NWS Phoenix, AZ
- Area
- Whole counties
County Imperial County, CA
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 28, 4:55 PM PDT | Thunderstorm Wind 59 | El Centro, CA | Peak wind gust of 59 mph reported at El Centro Naval Air Station. Nearby wind damage included power lines and poles down and a roof blown off a house in Brawley. |
NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.
The nearest sounding before it
Yuma Intl Airpor, AZ (KYUM), launched 12:00Z, 11.7 hours before the alert went out and 84 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.
- Mixed-layer CAPE
- 105 J/kg
- Mixed-layer CIN
- -242 J/kg
- Mixed-layer LCL
- 1611 m above ground
- 0-6 km bulk shear
- 16 kt
- 0-1 km storm-relative helicity
- 12 m²/s²
- 0-3 km storm-relative helicity
- 35 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at Jul 28, 2:50 PM PDT, 1 hour 54 minutes earlier.
Area forecast discussion, Jul 28, 2:50 PM PDT, 1 hour 54 minutes before
SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 250 PM MST WED JUL 28 1999 .SYNOPSIS... A MOIST SOUTH TO SOUTHEAST FLOW WILL CONTINUE OVER THE DESERT SOUTHWEST THROUGH THURSDAY. AN UPPER LEVEL DISTURBANCE WILL APPROACH THE FORECAST AREA AND INCREASE THE CHANCE FOR SHOWERS AND THUNDERSTORMS TONIGHT THROUGH MIDDAY THURSDAY. LOCALLY HEAVY RAINFALL CAN BE EXPECTED WITH THE MORE INTENSE STORMS. OTHERWISE...EXPECT VARIABLY CLOUDY SKIES WITH HUMID CONDITIONS TO PERSIST RIGHT ON THROUGH THE UPCOMING WEEKEND...ALONG WITH A CHANCE FOR MAINLY AFTERNOON THUNDERSTORMS OVER THE HIGHER TERRAIN AND NIGHTTIME STORMS OVER THE DESERTS. .DISCUSSION... PROBLEM OF THE DAY IS OBVIOUS...POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED FLASH FLOODING OVER PORTIONS OF OUR CWA. PRECIPITABLE WATER AMOUNTS STILL WELL ABOVE CLIMATOLOGY (GREATER THAN 1.75)...AND EVEN WITH HIGH TEMPS THIS AFTERNOON HELD DOWN BY MORNING CLOUD COVER AND SHOWERS...INSTABILITY FAR FROM NON-EXISTENT. TWO MID-UPPER LEVEL DISTURBANCES AFFECTING CWA PROMISE TO MAKE THIS FORECAST QUITE CHALLENGING AND LOADED WITH UNCERTAINTY. DISTURBANCE NUMBER 1 IS CURRENTLY SUPPORTING DEEP CONVECTION OVER FAR SOUTHEAST CALIFORNIA... WHILE DISTURBANCE NUMBER 2 (D2) MOVING TOWARD SOUTHEAST AZ IS SUPPORTING CONVECTION AT AND SOUTH OF TUCSON. ATTM...STILL FEEL THAT WIDESPREAD SHOWERS AND THUNDERSTORMS ARE A GOOD BET OVER SOUTH- CENTRAL AZ TONIGHT THANKS TO D2 DYNAMICS. WILL HILITE POTENTIAL FOR HEAVY RAINFALL SOUTH-CENTRAL AZ IN HWO. PER COORDINATION CALL WITH TUCSON...HAVE OPTED NOT TO ISSUE FFA FOR AREA AT THIS TIME...AS CONVECTION TO OUR SOUTH NOT OVERLY IMPRESSIVE. IF UPPER DISTURBANCE DOES WHAT I EXPECT...SHOULD SEE MORNING SHOWERS OVER MUCH OF SW AND S-CNTRL AZ THURSDAY...FOLLOWED BY PARTLY CLOUDY SKIES WITH ISOLATED THUNDERSTORMS MAINLY OVER HIGHER TERRAIN THURSDAY AFTN/EVENING. STORMS WILL CERTAINLY EXIST AND BE VIGOROUS OVER HIGHER TERRAIN GIVEN GREATER CAPE DUE TO SLIGHTLY WARMER MAX TEMPS NEXT TWO DAYS. WILL GO WITH AT LEAST MODERATELY WET MONSOON FORECAST IN EXTENDED AS UPPER HIGH OVER FOUR CORNERS + MOISTURE RICH ATMOSPHERE = ACTIVE CONVECTIVE AFTERNOONS AND NIGHTS. DG
In the hours before
Special weather statement, Jul 28, 3:34 PM PDT, 1 hour 10 minutes before
AZZ020>028-CAZ030>033-291200- HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE PHOENIX AZ 333 PM MST (333 PM PDT) WED JUL 28 1999 ...LOCALLY HEAVY RAINFALL POSSIBLE ESPECIALLY OVER SOUTH CENTRAL ARIZONA TONIGHT... THUNDERSTORMS ARE POSSIBLE OVER ALL OF THE FORECAST AREA LATE THIS AFTERNOON AND TONIGHT. THE AIRMASS IS EXTEMELY MOIST...SO ANY STORMS THAT FORM WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAIN. AT THIS TIME...THE BEST CHANCE FOR LOCALLY HEAVY RAINFALL WILL BE OVER SOUTH CENTRAL ARIZONA TONIGHT. THIS OUTLOOK WILL BE ISSUED ONLY ON DAYS WHEN SOME FORM OF HAZARDOUS WEATHER IS EXPECTED SOMEWHERE OVER THE PHOENIX AREA OF WARNING RESPONSIBILITY...WHICH INCLUDES SOUTH CENTRAL AND SOUTHWEST ARIZONA AS WELL AS FAR SOUTHEAST CALIFORNIA. FOR PURPOSES OF THIS OUTLOOK HAZARDOUS WEATHER REFERS TO ANY OF THE FOLLOWING...LOCALLY HEAVY RAINFALL WHICH RESULTS IN FLOODING AND RUNNING WASHES...SAND OR DUST STORM WHICH REDUCES VISIBILITY TO ONE QUARTER MILE OR LESS...DAMAGING WINDS IN EXCESS OF 57 MPH...AND HAIL AT LEAST THREE QUARTERS OF AN INCH IN DIAMETER. WHEN HAZARDOUS WEATHER IS IMMINENT OR OCCURRING...THE PHOENIX NATIONAL WEATHER SERVICE FORECAST OFFICE WILL PROVIDE IMPORTANT LIFE- SAVING INFORMATION IN THE FORM OF WARNINGS...FOLLOW UP STATEMENTS... AND SHORT TERM FORECASTS. STORM SPOTTER ACTIVATION MAY BE NECESSARY LATER TODAY. DG
The office that day
Everything else NWS Phoenix, AZ issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 27, 5:40 PM PDT | Severe Thunderstorm Warning | PSR | Gila | 60 min |
| Jul 27, 6:04 PM PDT | Flash Flood Warning | PSR | Gila | 91 min |
| Jul 28, 11:02 AM PDT | Flash Flood Warning | PSR | Maricopa | 88 min |
| Jul 28, 4:29 PM PDT | Flash Flood Warning | PSR | Imperial | 91 min |
Nearby
Severe Thunderstorm Warnings in California, 1999Every severe thunderstorm warning in 1999
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.