Alert archive / Minnesota / Tornado Watches in 1998

Tornado Watch 749

July 18, 199815 counties in Minnesota; 4 counties in North Dakota

The Storm Prediction Center issued this tornado watch at Jul 18, 1998, 5:15 PM CDT for 15 counties in Minnesota; 4 counties in North Dakota. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Jul 18, 1998, 5:15 PM CDT (22:15 UTC)
Expired: Jul 18, 1998, 11:00 PM CDT
In force: 6 hr
Issued by: the Storm Prediction Center

Counties Becker County, MN, Beltrami County, MN, Clay County, MN, Clearwater County, MN, Douglas County, MN, Grant County, MN, Hubbard County, MN, Mahnomen County, MN, Norman County, MN, Otter Tail County, MN, Pennington County, MN, Polk County, MN, Red Lake County, MN, Wadena County, MN, Wilkin County, MN, Cass County, ND, Ransom County, ND, Richland County, ND, Sargent County, ND

The radar

The Fargo/Grand Forks radar (KMVX), 105 km from the middle of the area, began a volume at 22:15 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.

Warnings issued inside it

10 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jul 18, 5:41 PM CDT	Tornado Warning	FGF	Pennington	34 min
Jul 18, 6:01 PM CDT	Severe Thunderstorm Warning	FGF	Red Lake	49 min
Jul 18, 6:33 PM CDT	Severe Thunderstorm Warning	FGF	Polk	32 min
Jul 18, 7:01 PM CDT	Severe Thunderstorm Warning	FGF	Clearwater	34 min
Jul 18, 7:11 PM CDT	Severe Thunderstorm Warning	FGF	Ransom	34 min
Jul 18, 7:25 PM CDT	Tornado Warning	FGF	Ransom	30 min
Jul 18, 7:44 PM CDT	Severe Thunderstorm Warning	FGF	Wilkin	46 min
Jul 18, 8:11 PM CDT	Severe Thunderstorm Warning	FGF	Richland	34 min
Jul 18, 8:42 PM CDT	Severe Thunderstorm Warning	FGF	Richland	18 min
Jul 18, 8:47 PM CDT	Tornado Warning	FGF	Wilkin	33 min

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 10.3 hours before the alert went out and 256 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: 1629 J/kg
Mixed-layer CIN: -175 J/kg
Mixed-layer LCL: 970 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 116 m²/s²
0-3 km storm-relative helicity: 175 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.2

Open this sounding in Storm Lab

The text

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

852 
WWUS9 KMKC 182145
SEL9  
MKC WW 182145
NDZ000-MNZ000-190400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 749
STORM PREDICTION CENTER NORMAN OK
445 PM CDT SAT JUL 18 1998

THE STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

   EASTERN NORTH DAKOTA                       
   NORTHWESTERN MINNESOTA                          

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 515 PM UNTIL
1100 PM CDT.

TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 65 STATUTE MILES EAST AND WEST
OF A LINE FROM 70 MILES SOUTH OF FARGO NORTH DAKOTA TO 40 MILES
EAST OF THIEF RIVER FALLS MINNESOTA.

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. 
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.


DISCUSSION...SURFACE BASED THUNDERSTORMS BEGINNING TO DEVELOP OVER
EXTREME NORTHWEST MN AND ERN ND EXPECTED TO INTENSIFY AND MOVE
EASTWARD ABOUT 30 KT.  WIND FIELDS SUGGEST ISOLATED SUPERCELLS
LIKELY WITH POTENTIAL FOR TORNADOES. 

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 70 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. 
MEAN STORM MOTION VECTOR 28035.


...JOHNS

455,0981 480,0964 480,0935 455,0952

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 18, 7:30 AM CDT	Severe Thunderstorm Watch	SPC	Becker, Clay, Kittson, Mahnomen, Marshall, Norman and 4 more	6 hr
Jul 18, 6:00 PM CDT	Tornado Watch	SPC	Traverse	5 hr

Nearby

Tornado Watches in Minnesota, 1998 Tornado Watches in North Dakota, 1998 Every tornado watch in 1998

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; radar from the NEXRAD Level II archive.