Alert archive / Alabama / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 103, NWS Mobile, AL

May 4, 1999Clarke County, Alabama

NWS Mobile, AL issued this severe thunderstorm warning at May 4, 1999, 4:04 PM CDT for Clarke County, Alabama. It was in force for 71 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
May 4, 1999, 4:04 PM CDT (21:04 UTC)
Expired
May 4, 1999, 5:15 PM CDT
In force
71 min
Issued by
NWS Mobile, AL
Area
Whole counties

County Clarke County, AL

The nearest sounding before it

Eglin AFB/Valpar, FL (KVPS), launched 12:00Z, 9.1 hours before the alert went out and 184 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-pSkew-T log-p diagram, Eglin AFB/Valpar, FL at 12:00Z on 1999-05-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Eglin AFB/Valpar, FL at 12:00Z on 1999-05-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 232 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1519 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
232 m²/s²
0-3 km storm-relative helicity
292 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.

999 
WUUS1 KMOB 042107 RRA
SVRMOB
ALC025-042215-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOBILE AL
404 PM CDT TUE MAY 4 1999

THE NATIONAL WEATHER SERVICE IN MOBILE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CLARKE COUNTY IN SOUTHWESTERN ALABAMA

* UNTIL 515 PM CDT

* AT 403 PM CDT... AS INDICATED BY DOPPLER RADAR A SEVERE THUNDERSTORM
  WAS LOCATED 10 MILES WEST OF THOMASVILLE OR 3 MILES SOUTH OF
  TALLAHATTA SPRINGS... MOVING NORTHEAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL REACH THE VICINITY OF -
  TALLAHATTA SPRINGS BY 405 PM CDT
  THOMASVILLE BY 420 PM CDT
  ROUNDHILL BY 425 PM CDT

WHEN THUNDERSTORMS ARE OCCURRING...PEOPLE SHOULD MOVE INSIDE A STRONG
BUILDING. DO NOT STAND BY WINDOWS. DO NOT USE TELEPHONES OR
ELECTRICAL APPLIANCES UNLESS IN AN EMERGENCY UNTIL THE STORM HAS
PASSED. MOTORISTS SHOULD NOT DRIVE INTO LOW WATER CROSSINGS.

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 Mobile, AL wrote its last area forecast discussion before this severe thunderstorm warning went out at May 4, 2:28 PM CDT, 1 hour 36 minutes earlier.

Area forecast discussion, May 4, 2:28 PM CDT, 1 hour 36 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
228 pM CDT TUE MAY 4 1999

MODELS INITIALIZED WELL AT 18Z WITH 986MB SFC LOW ACROSS CENTRAL KS
AND UPPER LEVEL TROF STACKED BACK OVER CO.  AVN SEEMS TO HAVE BEST
HANDLE ON WEAK SHORT WAVE ENERGY CURRENTLY TRACKING ACROSS MS-LA-AL
AND PUSHING EWD THIS AFTN.  THIS ENERGY COUPLED WITH AFTN HTG...
STRONG SFC MOISTURE CONVERGENCE AND BROAD AREA OF DIFFLUENT FLOW
ALOFT ARE PRODUCING SCATTERED STRONG-SVR TSTMS OVER PORTIONS OF FA
THIS AFTN. EXPECT SHORT WAVE ENERGY TO PUSH EAST OF AREA LATER
TONIGHT WITH A BREAK IN THE ACTIVITY LIKELY BEGINNING BY 9-10 PM TNGT
THRU WED MRNG.  BY EARLY WED AFTN...MODELS SHOW INCREASING CAPES
(2000-3000+ CAPES) AND THTA-E RIDGING ACROSS FA AS SFC FRONT MOVES
INTO WEST LA WITH APPROACHING UPPER LEVEL SHORT WAVE.  THIS SHOULD
RESULT IN DEVELOPING SCATTERED CONVECTION ACROSS MUCH OF FA BY WED
AFTN...THEN INCREASING IN COVERAGE WED NGT AS FRONT PUSHES INTO MS-SE
LA LATE WED NIGHT THRU EARLY THU MRNG WITH STRONG MOISTURE
CONVERGENCE AND INCREASING INSTABILITIES POOLED JUST OUT AHEAD.  AS
FRONT PUSHES INTO FA THU MRNG...EXPECT DECREASING POPS BY THU AFTN AS
BEST UPPER SUPPORT LIFTS WELL NE AND INSTABILITIES GET PUSHED EWD OUT
AHEAD OF FRONT. ALTHO ISOLATED SVR TSTMS WILL REMAIN POSSIBLE WED
AFTN-THU MRNG...NOT EXPECTING ANY WIDESPREAD THREAT HERE WITH MAIN
UPPER LEVEL PUNCH REMAINING WELL NORTH OF FA...BUT WILL MONITOR FOR
THE ISOLATED THREAT.  BEST QPF ACCUMULATIONS ARE EXPECTED FROM LATE
WED AFTN THRU EARLY THU MRNG WITH WIDESPREAD 1/4 TO 1/2 INCH LIKELY
WITH SOME ISOLATED 1-3 INCHES POSSIBLE.  FA REMAINS EXTREMELY DRY SO
FLASH FLOOD THREAT SHOULD REMAIN MINIMAL AT THIS TIME. GUIDANCE TEMPS
LOOK CLOSE...SO WILL NOT STRAY FAR THRU PERIOD.

LONG RANGE...FRONT WILL LIKELY STALL OVER COASTAL WATERS THU NIGHT
INTO FRI...THEN PUSH BACK NORTH AS WF OVER THE WEEKEND AS NEXT SYSTEM
TRACKS ACROSS NORTH CENTRAL U.S. AND SFC RIDGE BUILDS BACK IN FROM
FL.

MOB 68/82/68/80 4653  PNS 70/79/70/78 4653
DTS 70/79/70/78 4653  GZH 64/83/65/81 4653 39

The office that day

Everything else NWS Mobile, AL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 4, 11:57 AM CDTSevere Thunderstorm WarningMOBChoctaw48 min
May 4, 12:48 PM CDTSevere Thunderstorm WarningMOBMobile57 min
May 4, 1:30 PM CDTSevere Thunderstorm WarningMOBBaldwin75 min
May 4, 3:14 PM CDTSevere Thunderstorm WarningMOBBaldwin76 min

Nearby

Severe Thunderstorm Warnings in Alabama, 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; the sounding from the Mesonet's radiosonde archive.