Alert archive / Minnesota / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 76, NWS Duluth, MN

July 31, 2001Koochiching County, Minnesota

NWS Duluth, MN issued this severe thunderstorm warning at Jul 31, 2001, 7:35 PM CDT for Koochiching County, Minnesota. It was in force for 55 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 31, 2001, 7:35 PM CDT (00:35 UTC)
Expired
Jul 31, 2001, 8:30 PM CDT
In force
55 min
Issued by
NWS Duluth, MN
Area
Whole counties

County Koochiching County, MN

The radar

The Duluth radar (KDLH), 196 km from the middle of the area, began a volume at 00:39 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 31, 7:45 PM CDTThunderstorm Wind 60 EBirchdale, MNNumerous trees were reported blown down along State Highway 11 between Birchdale and Pelland. The wind speed is estimated.

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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 31, 4:00 PM CDTTornado WatchSPC6 hr

The nearest sounding before it

International Fa, MN (KINL), launched 00:00Z, 0.6 hours before the alert went out and 51 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, International Fa, MN at 00:00Z on 2001-08-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1223 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, International Fa, MN at 00:00Z on 2001-08-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 558 square meters per square second.19395878Sfc1 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
1223 J/kg
Mixed-layer CIN
-187 J/kg
Mixed-layer LCL
537 m above ground
0-6 km bulk shear
63 kt
0-1 km storm-relative helicity
558 m²/s²
0-3 km storm-relative helicity
694 m²/s²
Significant tornado parameter
0.0
Supercell composite
26.2

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 Duluth, MN wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 31, 2:50 PM CDT, 4 hours 45 minutes earlier.

Area forecast discussion, Jul 31, 2:50 PM CDT, 4 hours 45 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
250 PM CDT TUE JUL 31 2001

EXTREME INSTABILITY IN PLACE TNT WITH LIFTED INDICES -3 TO -7 AND
CAPES 2000 TO OVER 3000. STRONG 50 KTS+ LLJ DEVELOPS THIS EVENING
AND WITH THETA-E RIDGE BUILDING OVER NORTHERN MN...THE STAGE WILL BE
SET FOR THUNDERSTORMS WITH HEAVY RAIN. MODELS IN FAIRLY GOOD
AGREEMENT WITH MOVEMENT OF LOW/FRONTAL SYSTEM TNT... THEN AVN PUSHES
IT THRU NWRN WI WED MUCH FASTER THAN ETA. CHOSE TO GO WITH THE
SLOWER AND MORE CONSERVATIVE ETA...AND KEPT CHC OF PRECIP FOR ERN
CWA INTO WED MORNING.

PRECIPITALBE WATER OVER 2 INCHES...AND RAINFALL AMOUNTS OVER 3
INCHES NOT OUT OF THE QUESTION WITH SUCH A WATER-LOGGED ATMOSPHERE.
WILL GO WITH FLASH FLOOD WATCH FOR NORTHERN MN...GENERALLY NORTH OF
A LINE FROM WALKER TO TWO HARBORS. FLASH FLOOD GUIDANCE RANGES FROM
3-4 INCHES. RADAR ESTIMATES AVERAGE 1 TO 2 INCHES FOR MUCH OF THE
BORDER REGION WITH SOME 4-5 INCHE AMOUNTS FROM OVERNIGHT AND THIS
AFTERNOONS STORMS..SO GROUND IS VERY SATURATED.

HIGH PRESSURE BUILDS IN WEDNESDAY...FOR A DRIER AFTERNOON.  HIGH
KEEPS HOLD THROUGH THURSDAY.

.DLH...FLASH FLOOD WATCH NORTHERN MN

CLC

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 31, 8:08 PM CDTSevere Thunderstorm WarningDLHSaint Louis52 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2001Every severe thunderstorm warning in 2001

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.