Alert archive / Minnesota / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 249, NWS Grand Forks, ND

July 31, 2001Polk County, Minnesota

NWS Grand Forks, ND issued this severe thunderstorm warning at Jul 31, 2001, 7:58 PM CDT for Polk County, Minnesota. It was in force for 32 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, 7:58 PM CDT (00:58 UTC)
Expired: Jul 31, 2001, 8:30 PM CDT
In force: 32 min
Issued by: NWS Grand Forks, ND
Area: Whole counties

County Polk County, MN

The radar

The Fargo/Grand Forks radar (KMVX), 74 km from the middle of the area, began a volume at 01:01 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 31, 8:05 PM CDT	Hail 0.88	Fosston, 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 watch it was issued in

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

Issued	Product	Office	Lasted
Jul 31, 4:00 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

International Fa, MN (KINL), launched 00:00Z, 1.0 hours before the alert went out and 246 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: 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

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

000 
WUUS53 KFGF 010058
SVRFAR

MNC119-010130-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE EASTERN ND-GRAND FORKS
758 PM CDT TUE JUL 31 2001

THE NATIONAL WEATHER SERVICE IN GRAND FORKS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...

  SOUTHEASTERN POLK COUNTY IN NORTHWEST MINNESOTA.

* UNTIL 830 PM CDT.

* AT 756 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 2 MILES NORTH OF FOSSTON...OR ABOUT 40 MILES
  SOUTHEAST OF THIEF RIVER FALLS...MOVEMENT WAS TO THE NORTHEAST AT
  40 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...

  OLGA AT 805 PM CDT.

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

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1000 PM CDT TUESDAY EVENING
FOR NORTHWESTERN MINNESOTA AND EASTERN NORTH DAKOTA.


$$

14

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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 31, 3:25 PM CDT, 4 hours 33 minutes earlier.

Area forecast discussion, Jul 31, 3:25 PM CDT, 4 hours 33 minutes before

FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
325 PM CDT TUE JUL 31 2001

FORECAST CHALLENGE FOR TONIGHT AND WED IS PCPN. CURRENT SATELLITE
IMAGERY HAS ALL BUT SE CWFA CLOUDY. KMVX HAS SVR TSRA OVER N
CWFA...WITH OTHER TSRA TRYING TO GET ORGANIZED IN FRONTAL ZONE IN E
ND. LATEST MSAS SFC PRESSURE ANALYSIS HAS LOW PRESSURE CENTERED NEAR
MBG...WITH FRONT EXTENDING BET JMS-FAR TO GFK-DVL TO HCO. WHEN
COMPARING INITIALIZATION CONDITIONS TO MODELS...ETA INITIALIZED
BEST...BUT USED COMPROMISE SOLUTION AS NO MODEL HANDING SCENARIO
ENTIRELY. MODEL SOUNDINGS QUITE SATURATED WITH PW'S REMAINING AROUND
2.0 INCHES OVER CWFA THROUGH THE NIGHT. IN ADDITION...SFC LOW TRACKS
THROUGH CWFA OVERNIGHT...WITH GOOD 850 MB LLJ...NICE THETA-E
RIDGE...AS WELL AS A 700MB TROF AND UPPER LEVEL SHORTWAVE...ALL
SETTING SITES ON CWFA TO KEEP HEAVY RAIN AND SVR POTENTIAL TONIGHT.
WITH FFG VALUES FOR MAJORITY OF COUNTIES UNDER 2 INCHES...WILL KEEP
FFA OUT FOR CWFA TONIGHT...BUT WILL LET NIGHT SHIFT DETERMINE IF E
CWFA WILL NEED TO EXTEND FFA INTO WED. THANKS TO BIS AND DLH FOR
COORD.

FORECAST CHALLENGE FOR WED NIGHT AND THU IS TEMPS. STRONG CAA AHEAD
OF SFC HIGH WILL BRING BREEZY CONDITIONS TO CWFA ON WED. HIGH BUILDS
INTO CWFA BY 06Z THU...WITH GOOD 850 MB Q-VECTOR DIVERGENCE AND
WINDS GOING LIGHT AND VARIABLE...EXPECT TEMPS TO FALL INTO 55 TO 65
DEGREE RANGE. THEN ON THU...SFC HIGH MOVES E WITH SE-S RETURN FLOW
SETTING UP...ALLOWING TEMPS TO BUMP BACK INTO THE LOW TO MIDDLE 80S.

EXTENDED RANGE MODELS IN REASONABLY GOOD AGREEMENT IN SFC AND MID
LEVEL FEATURES THROUGH PERIOD IN BUILDING UPPER RIDGE INTO FORECAST
AREA. MODELS CONSISTENT IN SHOWING AREA OF LOW PRESSURE OVR DAKOTAS
WHICH MAY BRING CHC OF MAINLY NIGHTTIME TSRA THIS WEEKEND. FOLLOWING
THIS AN UPPER RIDGE BUILDS...SO WARM TEMPS AT 700MB MAY SQUELCH ANY
CHANCE FOR CONVECTION. FOR NOW WILL KEEP FCST DRY FOR EARLY NEXT
WEEK BECAUSE OF POTENTIAL CAPPING. AT OR ABOVE AVERAGE TEMPS TEMPS
TO CONTINUE WITH WARMEST TEMPS FIRST PART OF NEXT WEEK.

.FGF...FLASH FLOOD WATCH FULL CWFA TONIGHT.

NG/AMV

In the hours before

Local storm report, Jul 31, 5:15 PM CDT, 2 hours 43 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE EASTERN NORTH DAKOTA/GRAND FORKS
515 PM CDT TUE JUL 31 2001

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0425 AM    12 ESE ADA                MN   WIND DAMAGE
07/31/01   NORMAN                         LARGE BRANCHES DOWN IN
                                          TWIN VALLEY

0445 AM    HALSTAD                   MN   WIND DAMAGE
07/31/01   NORMAN                         DOWNED POWER POLES

0455 AM    1 E GULLY                 MN   WIND DAMAGE
07/31/01   POLK                           TREES DOWN ALONG HWY 92

0230 PM    5 NW GRYGLA               MN   .75 INCH HAIL
07/31/01   MARSHALL                       HAIL FOR 5 MINUTES

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 31, 7:30 PM CDT	Severe Thunderstorm Warning	FGF	Polk, Red Lake	30 min
Jul 31, 8:08 PM CDT	Severe Thunderstorm Warning	FGF	Clearwater	52 min
Jul 31, 8:23 PM CDT	Severe Thunderstorm Warning	FGF	Pennington	37 min
Jul 31, 8:43 PM CDT	Severe Thunderstorm Warning	FGF	Beltrami	32 min
Jul 31, 9:00 PM CDT	Severe Thunderstorm Warning	FGF	Marshall, Pennington	30 min
Jul 31, 10:05 PM CDT	Flash Flood Warning	FGF	Clearwater	5 hr
Jul 31, 11:10 PM CDT	Flash Flood Warning	FGF	Beltrami, Lake of the Woods	4 hr

Nearby

Severe Thunderstorm Warnings in Minnesota, 2001 Every 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.