Alert archive / Nebraska / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 33, NWS Omaha, NE

May 3, 1999Wayne County, Nebraska

NWS Omaha, NE issued this severe thunderstorm warning at May 3, 1999, 8:20 PM CDT for Wayne County, Nebraska. It was in force for 45 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: May 3, 1999, 8:20 PM CDT (01:20 UTC)
Expired: May 3, 1999, 9:05 PM CDT
In force: 45 min
Issued by: NWS Omaha, NE
Area: Whole counties

County Wayne County, NE

The radar

The Omaha radar (KOAX), 117 km from the middle of the area, began a volume at 01:22 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.

What was reported inside it

Time	Report	Where	Remark
May 3, 8:45 PM CDT	Hail 0.88	Wayne, NE

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

Omaha, NE (KOAX), launched 00:00Z, 1.3 hours before the alert went out and 117 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: 1468 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 1303 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 89 m²/s²
0-3 km storm-relative helicity: 242 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 6.5

Open this sounding in Storm Lab

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 Omaha, NE wrote its last area forecast discussion before this severe thunderstorm warning went out at May 3, 2:35 PM CDT, 5 hours 45 minutes earlier.

Area forecast discussion, May 3, 2:35 PM CDT, 5 hours 45 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
235 PM CDT MON MAY 3 1999

18Z SOUNDING SHOWS SOME INCREASED MOISTR ADVECTION AND SFC DEWPOINTS
UP TO 60 AT HSI LNK BIE FNB AND OFF.  ALL THREE MODELS WOULD INDICATE
IMPROVED UPPER SUPPORT LATER TONIGHT.  TOP AND OAX SOUNDINGS SHOWED ABOUT
57 AND 78 B- WITH LITTLE PROB WITH SECOND INVERSION ALOFT.  WITH JET
JUST ROTATING INTO SRN SIDE OF CIRC THIS EVE...AND THE PRONOUNCED S TO
N JET IN FRONT NOT PRESENT PRECIP MAY HOLD OFF UNTIL AFT MIDNIGHT.

ALL THREE MODELS WANT TO RAPIDLY EXPAND THE MOISTURE THROUGH THE STACK
TO 12Z...AND ALSO UNDERGO SOME SERIOUS DESTABLIZATION.  OVERNIGHT
ACTIVITY LIKELY TO LAST INTO TUE.  WITH RELATIVE HIGH RH BUT WARM
AIRMASS WILL FAVOR LOWER 70S OVER UPPER 60S TUE.  WITH VERY DISTINCT
COLD FRONT LIKELY TUE NIGHT COULD EXPECT FRONTAL WEATHER WITH SOMEWHAT
COOLER TEMPS TUE NIGHT AND LOWER TO MID 60S ON WED NOT UNWARRANTED.

.OMA...NONE
POERS

In the hours before

Special weather statement, May 3, 5:30 PM CDT, 2 hours 50 minutes before

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-041200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
530 PM CDT MON MAY 3 1999

...SEVERE WEATHER OUTLOOK FOR EASTERN NEBRASKA AND SOUTHWEST IOWA...

SPOTTER ACTION...
STORM SPOTTER ACTIVATION MAY BE REQUIRED TONIGHT IN EASTERN NEBRASKA
AND SOUTHWEST IOWA.

DISCUSSION...
AN UNSTABLE AND MOIST AIR MASS IS IN PLACE ACROSS EASTERN NEBRASKA AND
SOUTHWEST IOWA. STRONG SOUTH WINDS THROUGH THE NIGHT WILL LEAD TO AN
EVEN FURTHER INCREASE IN GULF MOISTURE INTO THE REGION. THIS AIR MASS
WILL INTERACT WITH DISTURBANCES IN THE UPPER ATMOSPHERE MOVING INTO THE
PLAINS AND SURFACE BOUNDARIES...TO BRING A CHANCE FOR THUNDERSTORMS TO
THE REGION TONIGHT.

DUE TO THE DEGREE OF INSTABILITY...SOME OF THESE STORMS COULD BECOME
SEVERE. LARGE HAIL AND DAMAGING WIND GUSTS APPEAR TO BE THE MAIN RISK.
HOWEVER ISOLATED TORNADOES ARE POSSIBLE BASED ON WIND SHEAR PROFILES IN
THE LOWER ATMOSPHERE.

GW

The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 3, 7:20 PM CDT	Severe Thunderstorm Warning	OAX	Butler	50 min
May 3, 7:39 PM CDT	Severe Thunderstorm Warning	OAX	Cuming	51 min
May 3, 7:50 PM CDT	Severe Thunderstorm Warning	OAX	Colfax	65 min
May 3, 7:55 PM CDT	Severe Thunderstorm Warning	OAX	Stanton	50 min
May 3, 8:02 PM CDT	Severe Thunderstorm Warning	OAX	Dodge	48 min
May 3, 8:31 PM CDT	Tornado Warning	OAX	Antelope	34 min
May 3, 8:33 PM CDT	Severe Thunderstorm Warning	OAX	Pierce	47 min
May 3, 8:52 PM CDT	Tornado Warning	OAX	Knox	48 min
May 3, 8:56 PM CDT	Severe Thunderstorm Warning	OAX	Cedar, Knox	64 min
May 3, 9:30 PM CDT	Tornado Warning	OAX	Cedar	50 min
May 3, 9:38 PM CDT	Tornado Warning	OAX	Knox	32 min
May 4, 6:25 AM CDT	Severe Thunderstorm Warning	OAX	Cass, Otoe	45 min
May 4, 7:39 AM CDT	Severe Thunderstorm Warning	OAX	Douglas, Washington	31 min

Nearby

Severe Thunderstorm Warnings in Nebraska, 1999 Every 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; radar from the NEXRAD Level II archive.