Alert archive / Arizona / Severe Thunderstorm Warnings in 1999
Severe Thunderstorm Warning 18, NWS Phoenix, AZ
NWS Phoenix, AZ issued this severe thunderstorm warning at Jul 14, 1999, 3:47 PM MST for Maricopa County, Arizona. It was in force for 48 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 14, 1999, 3:47 PM MST (22:47 UTC)
- Expired
- Jul 14, 1999, 4:35 PM MST
- In force
- 48 min
- Issued by
- NWS Phoenix, AZ
- Area
- Whole counties
County Maricopa County, AZ
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 14, 4:27 PM MST | Thunderstorm Wind 60 | Mesa, AZ | Trees and power poles downed.. Numerous reports of street flooding. |
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
Phoenix, AZ (KPSR), launched 12:00Z, 10.8 hours before the alert went out and 49 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
- 513 J/kg
- Mixed-layer CIN
- -153 J/kg
- Mixed-layer LCL
- 1695 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 47 m²/s²
- 0-3 km storm-relative helicity
- 77 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
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 14, 2:45 PM MST, 1 hour 2 minutes earlier.
Area forecast discussion, Jul 14, 2:45 PM MST, 1 hour 2 minutes before
SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 245 PM MST WED JUL 14 1999 .SYNOPSIS... A MOIST AIRMASS IS MOVING SLOWLY EAST ACROSS SOUTH CENTRAL AZ TONIGHT. A BROAD TROUGH OF LOW PRESSURE MOVES TO THE EAST TONIGHT TRIGGERING SCATTERED THUNDERSTORMS WITH HEAVY RAINFALL IN SOUTH CENTRAL AZ. A SOUTHWEST FLOW ALOFT ON THURSDAY WILL BRING SLIGHTLY DRIER AIR INTO THE SOUTHWEST AND SOUTH CENTRAL AREA. CHANCE OF AFTERNOON THUNDERTORMS CONTINUES MAINLY TO THE EAST ON FRIDAY AND INTO THE WEEKEND. .DISCUSSION... DEEP CONVECTION OVER SOUTH CENTRAL MIDDAY TODAY HAS TEMPORAIRLY DIMINISHIED THUNDERTORMS LATE THIS AFTERNOON. HOWEVER THE STRONG THUNDERSTORMS SHOULD RETURN THIS EVENING...TRIGGERING ON THE OLD OUTFLOW BOUNDAIRIES FROM THE PREVIOUS STORMS...A MOVE NORTHEAST ACROSS THE SAME AREAS THAT HAD RAINS EARLIER TODAY. THE SUBTLE AXIS OF A BROAD TROUGH ALOFT SHOULD SWING TO THE EAST OF SOUTH CENTRAL AZ BY 06Z TONIGHT. AFTER THE AXIS PASSAGE CNVCTV ACTIVITY SHOULD DMSH. A WEAK RDIGE FOLLOWS...INTO OUR AREA ON THURSDAY...THEN A E PAC TROUGH DEEPENS SW OF SRN CA...ON FRIDAY BRINGING A BETTER DEFINED SOUTHWEST FLOW INTO THE AREA. THE E PAC TROUGH SHD BE THE DOMINATE FEATURE THOUGH THE WEEKEND. PERHAPS HEARLDING A SLIGHTLY DRIER CLIME IN THE SOUTHWEST REGION OF OUR AREA GOING INTO EARLY NEXT WEEK. IN THE MEANTIME...A FLASH FLOOD WATCH WILL BE IN EFFECT UNTIL 11 PM MST FOR CENTRAL AZ...MARICOPA...SOUTHERN GILA...AND NORTHWEST PINAL COUNTY.
The office that day
Everything else NWS Phoenix, AZ issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 13, 7:03 PM MST | Flash Flood Warning | PSR | Maricopa | 3 hr |
| Jul 14, 1:23 PM MST | Severe Thunderstorm Warning | PSR | Gila | 62 min |
| Jul 14, 3:25 PM MST | Severe Thunderstorm Warning | PSR | Maricopa | 60 min |
| Jul 14, 4:07 PM MST | Flash Flood Warning | PSR | Maricopa | 93 min |
| Jul 14, 4:24 PM MST | Severe Thunderstorm Warning | PSR | Pinal | 46 min |
| Jul 14, 4:38 PM MST | Severe Thunderstorm Warning | PSR | Maricopa | 37 min |
Nearby
Severe Thunderstorm Warnings in Arizona, 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.