Alert archive / Minnesota / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 128, NWS Twin Cities, MN

July 13, 1999Hennepin County, Wright County, Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at Jul 13, 1999, 10:50 PM CDT for Hennepin County, Wright County, Minnesota. It was in force for 40 min. 3 reports 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 13, 1999, 10:50 PM CDT (03:50 UTC)
Expired: Jul 13, 1999, 11:30 PM CDT
In force: 40 min
Issued by: NWS Twin Cities, MN
Area: Whole counties

Counties Hennepin County, MN, Wright County, MN

The radar

The Minneapolis radar (KMPX), 29 km from the middle of the area, began a volume at 03:50 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
Jul 13, 10:55 PM CDT	Hail 1	Delano, MN	Occurred in the city of Rockford on the Wright County side.
Jul 13, 10:55 PM CDT	Hail 1	Rockford, MN	Rockford straddles both Hennepin and Wright Counties.
Jul 13, 11:00 PM CDT	Hail 1.75	Buffalo, MN

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

Minneapolis, MN (KMPX), launched 00:00Z, 3.8 hours before the alert went out and 28 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: 1643 J/kg
Mixed-layer CIN: -105 J/kg
Mixed-layer LCL: 1437 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 70 m²/s²
0-3 km storm-relative helicity: 152 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 1.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KMPX 140352 RRA
SVRMSP
MNC053-171-140430-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TWIN CITIES-CHANHASSEN MN
1050 PM CDT TUE JUL 13 1999


THE NATIONAL WEATHER SERVICE IN TWIN CITIES-CHANHASSEN MN HAS ISSUED
A

* SEVERE THUNDERSTORM WARNING FOR...
  HENNEPIN COUNTY IN EAST CENTRAL MINNESOTA
  EASTERN WRIGHT COUNTY IN CENTRAL MINNESOTA

* UNTIL 1130 PM CDT

* AT 1050 PM CDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM WITH LARGE HAIL AND DAMAGING WINDS 2 MILES EAST
  OF MONTROSE...OR ABOUT 28 MILES NORTHEAST OF HUTCHINSON...MOVING
  NORTHEAST AT 25 MPH.

* SOME LOCATIONS AFFECTED BY THIS STORM INCLUDE...
  PLYMOUTH
  MAPLE GROVE
  BUFFALO
  MINNEAPOLIS

LARGE HAIL AND DAMAGING WINDS ARE LIKELY WITH THIS STORM. TAKE COVER
IN A STURDY BUILDING AND STAY AWAY FROM WINDOWS.

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 Twin Cities, MN wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 13, 8:45 PM CDT, 2 hours 5 minutes earlier.

Area forecast discussion, Jul 13, 8:45 PM CDT, 2 hours 5 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
845 PM CDT TUE JUL 13 1999

FORECAST CONCERNS ARE CONVECTION CHANCES TONIGHT. STORMS TO OUR NORTH
DEVELOPED ALONG OLD BOUNDARY FROM LAST NIGHT AND ALONG INSTABILITY
GRADIENT..ALTHOUGH NOT THAT STRONG. STORM HAVE BEEN WEAKENING WITH
NOT REAL STRONG LOW LEVEL FLOW. STORMS IN ND COULD STILL RIDE SE
INTO AREA LATE TONIGHT. 21Z RUB HAD CARRIED SOME 850 MB MOIST CONV
FROM S MN UP INTO N MN OVERNIGHT BY 06Z. OF OTHER CONCERN IS
PERSISTENT AREA OF MOIST CONV OVER PARTS OF SW MN AND SOME ISOLATED
CELLS HAVE DEVELOPED IN FAR SW MN. THESE ARE CURRENTLY RIDING ESE
AND WILL PROBABLY JUST PASS SOUTH OF OUR AREA. WILL HOWEVER..THROW
IN A LIGHT CHANCE FOR PARTS OF SW DUE TO SIG MOIST CONV. 00Z
SOUNDINGS FOR BOTH ABR AND MPX SHOW A BIT OF A CAP AND NOT A GREAT
DEAL OF MOISTURE. MID LEVEL WINDS NOT REAL IMPRESSIVE EITHER. THINK
MOST ACTIVITY WILL REMAIN WIDELY SCATTERED.

.MSP...NONE
RICHARDSON

The office that day

Everything else NWS Twin Cities, MN issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 13, 9:05 PM CDT	Severe Thunderstorm Warning	MPX	Redwood	25 min
Jul 13, 11:11 PM CDT	Severe Thunderstorm Warning	MPX	Anoka	34 min
Jul 13, 11:32 PM CDT	Severe Thunderstorm Warning	MPX	Wright	28 min
Jul 13, 11:37 PM CDT	Severe Thunderstorm Warning	MPX	Chisago	23 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 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.