Alert archive / Minnesota / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 132, NWS Grand Forks, ND

July 21, 2002Grant County, Otter Tail County, Wadena County, Minnesota

NWS Grand Forks, ND issued this severe thunderstorm warning at Jul 21, 2002, 6:45 AM CDT for Grant County, Otter Tail County, Wadena County, Minnesota. It was in force for 60 min. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 21, 2002, 6:45 AM CDT (11:45 UTC)
Expired
Jul 21, 2002, 7:45 AM CDT
In force
60 min
Issued by
NWS Grand Forks, ND
Area
Counties, with a storm outline in the text

Counties Grant County, MN, Otter Tail County, MN, Wadena County, MN

The radar

The Fargo/Grand Forks radar (KMVX), 195 km from the middle of the area, began a volume at 11:49 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

TimeReportWhereRemark
Jul 21, 7:00 AM CDTThunderstorm WindBattle Lake, MNNumerous trees were blown down, several falling on garages.
Jul 21, 7:10 AM CDTThunderstorm WindHenning, MNPower poles were blown down by the strong wind. A tree also fell on the city playground equipment, causing a total loss. A new church being constructed was also flattened.
Jul 21, 7:28 AM CDTThunderstorm Wind 52 MVerndale, MNA MNDOT RWIS site measured a 60 mph wind gust.

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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 11.8 hours before the alert went out and 219 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, Minneapolis, MN at 00:00Z on 2002-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4791 joules per kilogram.LCLLFCEL10008507005003002001001 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, Minneapolis, MN at 00:00Z on 2002-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 269 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
4791 J/kg
Mixed-layer CIN
-73 J/kg
Mixed-layer LCL
842 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
269 m²/s²
0-3 km storm-relative helicity
412 m²/s²
Significant tornado parameter
7.4
Supercell composite
49.7

Open this sounding in Storm Lab

The text

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

850 
WUUS53 KFGF 211145
SVRFAR
MNC051-111-159-211245-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS
644 AM CDT SUN JUL 21 2002

THE NATIONAL WEATHER SERVICE IN GRAND FORKS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...

  WADENA COUNTY IN CENTRAL MINNESOTA...
  GRANT COUNTY IN WEST CENTRAL MINNESOTA AND   
  SOUTHERN OTTER TAIL COUNTY IN WEST CENTRAL MINNESOTA.

* UNTIL 745 AM CDT.

* AT 643 AM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THE
  LEADING EDGE OF SEVERE THUNDERSTORMS ALONG A LINE EXTENDING FROM 3
  MILES SOUTHWEST OF FERGUS FALLS TO 34 MILES SOUTH OF FERGUS
  FALLS...MOVEMENT WAS TO THE NORTHEAST AT 20 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...

  HOFFMAN AT 645 AM...
  FERGUS FALLS AT 650 AM...
  DALTON AT 655 AM AND
  ERDAHL AT 700 AM.

THIS THUNDERSTORM HAS A HISTORY OF DAMAGING WINDS...EXPECT WIND GUST 
UP TO 90 MPH WITH THIS STORM.

REMEMBER SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE
TORNADOES WITH LITTLE OR NO ADVANCE WARNING.

LAT...LON 4629 9628 4574 9595 4624 9455 4664 9489


8

NNNN

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 Grand Forks, ND wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 21, 2:05 AM CDT, 4 hours 40 minutes earlier.

Area forecast discussion, Jul 21, 2:05 AM CDT, 4 hours 40 minutes before
FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
205 AM CDT SUN JUL 21 2002

FORECAST CHALLENGE IS PRECIP THREAT TODAY...THEN TEMPS

.OVERVIEW...
MAIN SFC COLD FRONT STILL SLOWLY PUSHING INTO NORTHEAST ND THIS
AM...WITH ABUNDANT MOISTURE/INSTABILITY FROM GFK AND POINTS SOUTH
AND EAST. ONE AREA OF ELEVATED CONVECTION IN CENTRAL MN JUST EAST OF
AREA IN STRONG 850MB WARM AIR ADVECTION...ANOTHER PUSHING INTO NORTH
CENTRAL SD IN LEFT EXIT REGION OF 40KT 850MB JET AHEAD OF 500MB
SHORTWAVE MOVING INTO WESTERN DAKOTAS. MODELS STILL HAVING HARD TIME
WITH CURRENT SET UP...BUT ETA DID BEST WITH MOISTURE/INSTABILITY SO
WILL UTILIZE.

.SHORT TERM...
WILL MENTION PATCHY FOG IN ALL BUT NORTHERN ZONES THIS
MORNING...WITH ABUNDANT LOW LEVEL MOISTURE AND WEAK SFC FLOW.
MAIN 850MB FRONT AND UPPER SUPPORT MOVES THROUGH REGION
TODAY...EXPECT A ROUND OF THUNDERSTORMS ACROSS SOUTHERN 2/3 OF FA
SOUTH OF A GFK TO BJI LINE. CAPES STILL AROUND 2000J/KG FROM 12-18Z
IN FAR SOUTH...SO WOULDN/T RULE OUT AN ISOLATED SEVERE EVENT HERE
WITH NEW SLIGHT RISK AREA IN SWODY1 NEAR SOUTHEAST REGION. BEST
850MB COOLING WORKS INTO REGION THIS AFTERNOON...SO ONLY THING THAT
WILL LIMIT INSOLATION IS CLOUD COVER. EXPECT TEMPS TO BE ABOUT 5
DEGREES COOLER THAN YESTERDAY...AS DRIER AIR FILTERS INTO REGION BY
AFTERNOON.

.LONG TERM...
850MB TEMPS COOL TO AROUND +8C BY MONDAY AFTERNOON...AS DRY HIGH
PRESSURE SETTLES OVER REGION BY TUESDAY. THIS WILL MEAN TEMPS BELOW
NORMAL FOR MONDAY TUESDAY...WITH LOWS TUESDAY MORNING INTO THE UPPER
40S NORTH TO AROUND 50 SOUTH...ALMOST 20 DEGREES BELOW NORMAL.

.EXTENDED...
NO CHANGES PLANNED AT THIS TIME.

.FGF...NONE.

KELLENBENZ

The office that day

Everything else NWS Grand Forks, ND issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 21, 5:48 AM CDTSevere Thunderstorm WarningFGFGrant, Otter Tail, Wilkin57 min
Jul 21, 7:43 AM CDTSevere Thunderstorm WarningFGFWadena32 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2002Every severe thunderstorm warning in 2002

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.