Oppressive evening heat: Storms fade

Update 5:30pm:

The Twin Cities reached the highest heat index value of the year so far at 5pm tonight. The temperature at MSP was 91 with a tropical dew point of 78. That makes an oppressive heat index of 106 degrees in the metro!

It appears the line of storms west of the metro may fade this evening, but a severe thunderstorm watch remains in effect. If storms do not develop, NWS may cancel portions of the watch early this evening. Most of the tornadic and severe weather dynamics have shifted east into Wisconsin tonight.

A cool front will pass thorough later tonight bringing relief in the form of cooler temps and much lower dew points in the 50s by morning.

Stay cool!

PH

Update 4:45pm:

New severe thunderstorm watch includes the Twin Cities until 10 pm tonight. One more line of storms may deveop and move toward the metro this evening.

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More damage reports from storms moving through Wisconsin, including trees down in Menomonie.

PH

MPX: Spring Valley [Pierce Co, WI] law enforcement reports TSTM WND DMG at 03:20 PM CDT — numerous trees down from spring valley east to the dunn co border

MPX: Menomonie [Dunn Co, WI] law enforcement reports TSTM WND DMG at 03:25 PM CDT — trees down from the pierce co boarder east to menomonie.

MPX: 2 Ssw Menomonie [Dunn Co, WI] trained spotter reports TSTM WND DMG at 03:35 PM CDT — 4 inch diameter trees down onto power lines.

MPX: Menomonie [Dunn Co, WI] trained spotter reports TSTM WND DMG at 03:30 PM CDT — many trees blown down in north memomonie. street blocked by downed trees. some trees downed onto power lines. time estimated.

Update 4:15pm:

Tornado watch cancelled for the metro, but other wathces remain in effect.

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Severe thunderstorm watch until 10pm tonight

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Tornado watch for Wisconsin until 7pm

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Impressive GOES 1km vis image of thunderstorms complexes mushrooming over the area.

MPX: 2 Nne Haugen [Barron Co, WI] trained spotter reports HEAVY RAIN of M4.40 INCH at 04:00 PM CDT — total rainfall for today

MPX: Hastings [Dakota Co, MN] trained spotter reports TSTM WND DMG at 02:45 PM CDT — 2 ft diameter tree snapped in half at 19th and vermillion st. 1 ft diameter tree sheared in half and blocking fraser st.

Update 3:40pm:

All clear in the metro for now.

Storms moving east through SE Mn & Wicsonsin. Another batch in central Minnesota will have to be watched.

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That may be it for severe weather for the metro and much of southern Minnesota, but we’ll have to keep one eye out for any further development until the front comes through late tonight.

PH

Meanwhile, storm reports continue to flow into the weather lab…

MPX continues Tornado Warning for Benton, Stearns [MN] till 4:15 PM CDT …AT 402 PM CDT…TRAINED WEATHER SPOTTERS REPORTED A ROTATING WALL CLOUD SOUTH OF HOLDINGFORD AROUND 355 PM. THIS WALL CLOUD WAS LOCATED NEAR ST STEPHEN…OR 12 MILES NORTHWEST OF ST CLOUD…MOVING EAST AT 45 MPH.

MPX: Baldwin [St. Croix Co, WI] trained spotter reports TSTM WND DMG at 03:20 PM CDT — 2 semi trailers blown off road near baldwin. injuries reported. trees also down in area.

MPX: Hampton [Dakota Co, MN] emergency mngr reports TSTM WND DMG at 02:45 PM CDT — trees and powerlines down at intersection of hwy 47 and 52.

Update 3pm:

Tornado warnings continue in the sotueast metro and western Wisconsin. There have been reports of tornadoes on the ground and damage.

There are also tornadic storms in central Minnesota.

Reports below.

PH

MPX: Boyceville [Dunn Co, WI] law enforcement reports FUNNEL CLOUD at 03:24 PM CDT — reported by intersection of county rd d and x near county line.

MPX: Woodville [St. Croix Co, WI] amateur radio reports TSTM WND DMG at 03:00 PM CDT — tree limbs in excess of 4 inches down

MPX: 2 S Sauk Centre [Stearns Co, MN] amateur radio reports FUNNEL CLOUD at 03:15 PM CDT —

MPX: 3 Ssw Sauk Centre [Stearns Co, MN] trained spotter reports FUNNEL CLOUD at 03:10 PM CDT — rapidly rotating wall cloud reported.

MPX: 5 Sw Glenwood [Pope Co, MN] public reports FUNNEL CLOUD at 02:42 PM CDT — public report of funnel cloud on highway 28 between glenwood and starbuck airport near lake minnewaska. relayed by county dispatch.

MPX: Lakeville [Dakota Co, MN] awos reports TSTM WND GST of M62 MPH at 02:28 PM CDT — measured at lakeville airport

MPX: 1 N River Falls [St. Croix Co, WI] emergency mngr reports FUNNEL CLOUD at 02:58 PM CDT — at hwy 35 co rd u. a trained spotter also reported funnel at county trunk m and apollo rd.

MPX: New Market [Scott Co, MN] public reports HAIL of quarter size (E1.00 INCH) at 02:45 PM CDT — hail cracked windshield of car.

MPX: 4 S Farmington [Dakota Co, MN] public reports TORNADO at 02:40 PM CDT — relayed by faa employee.

MPX: 2 Se Credit River [Scott Co, MN] law enforcement reports TSTM WND DMG at 02:23 PM CDT — camper rolled over at intersection of hwy 8 and 91.

MPX: 3 N New Market [Scott Co, MN] emergency mngr reports TSTM WND DMG at 02:23 PM CDT — trees and branches down at intersction of co rd 8 and 91.

mpxchat 2010/07/14 2:45 PM iembot MPX: 2 Nw Randolph [Dakota Co, MN] storm chaser reports TORNADO at 02:43 PM CDT —

MPX: Lakeville [Dakota Co, MN] law enforcement reports TORNADO at 02:40 PM CDT — tornado reported by law enforcement in southern lakeville. another report of a tornado from 2 miles s of lakeville at intersection of interstate 35 and hwy 19. vehicle blown off road in that location.

BULLETIN – IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WARNING

NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN

211 PM CDT WED JUL 14 2010

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR…

CENTRAL DAKOTA COUNTY IN EAST CENTRAL MINNESOTA…

SOUTHEASTERN SCOTT COUNTY IN EAST CENTRAL MINNESOTA…

* UNTIL 300 PM CDT

* AT 209 PM CDT…RADAR INDICATED A SEVERE THUNDERSTORM…CAPABLE OF

PRODUCING QUARTER SIZE HAIL AND DAMAGING WINDS IN EXCESS OF 60 MPH.

THIS STORM WAS LOCATED 5 MILES WEST OF NEW MARKET…OR ABOUT 22

MILES NORTH OF FARIBAULT…AND MOVING NORTHEAST AT 35 MPH.

Update 2:15pm:

Heavy storms developing in eastern metro and south heading into Dakota and Goodhue counties. be alert for downpours, hail, lightning and possible damaging winds.

PH

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Update 1:45pm:

Twin Cities NWS issues forecast discussion calling for cap (a warm layer limiting T-Storm development so far) to break around 4pm. Explosive T-Storm growth could occur when the cap breaks, with storms quickly turning severe. Text below.

WHEN THUNDERSTORMS DO DEVELOP…CAPE…INSTABILITY IN THE

3000-5000 J/KG RANGE WILL RESULT IN EXPLOSIVE GROWTH IN

THUNDERSTORMS…WHICH WILL LIKELY QUICKLY BE SEVERE. THIS WILL

NEED TO MONITORED VERY CLOSELY THROUGH THE AFTERNOON AS

SIGNIFICANT IMPACTS ARE POSSIBLE AT KMSP/KRNH/KEAU. FRONT WILL CLEAR

KEAU BY 04-5Z…WHEN ALL TSRA SHOULD BE DONE.

KMSP…CONFIDENCE IN SIGNIFICANT TSRA ACTIVITY IMPACTING THE VCNTY

OF THE FIELD STILL REMAINS HIGH AT THIS POINT…BASED ON

FORECASTS FROM SEVERAL RUNS OF THE RUC NOW SHOWING THE CAP

BREAKING AT MSP AROUND 21Z. HARD TO SAY AT THIS POINT IF THE FIELD

WILL TAKE A DIRECT HIT…BUT DENSE COVERAGE OF TSRA EXPECTED

AROUND THE TWIN CITIES WILL LIKELY CREATE HAVOC IN SOME OF THE

DEPARTURE/ARRIVAL GATES.

Update 1:15pm:

Storms are beginning to refire north of the metro. We may see a line extend south into the metro in the next hour or two. Additional stomrs may also deveop west.

Here’s a radar archive through 1pm as the morning storms raced through north of the metro and caused damage in NW Wisconsin.

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SPC is still watching this area for development, but clouds have limitied development as we discussed this morning with Cathy Wurzer on Morning Edition.

From SPC:

ATTENDANT

CLOUDS ARE LIMITING DIABATIC HEATING OVER MUCH OF THIS AREA EXCEPT

FOR IA INTO SRN MN. PERSISTENT ASCENT AND HEIGHT FALLS DOWNSTREAM

FROM THE SHORTWAVE TROUGH AND WARMING OF BOUNDARY LAYER MAY

EVENTUALLY WEAKEN THE CAP SUFFICIENTLY FOR SURFACE BASED STORMS TO

REDEVELOP OVER SRN MN.

PH

Update 11am:

Duluth NWS receiving reports of widespread wind damage in the NW Wisconsin lake country and in Cloquet and Pine City. Derecheo in progress.

DLH: Grantsburg [Burnett Co, WI] trained spotter reports HEAVY RAIN of M1.12 INCH at 10:05 AM CDT — 1.12 inches of rain in 20-25 minutes.

DLH: 2 Ne Hayward [Sawyer Co, WI] asos reports TSTM WND GST of M49 MPH at 10:39 AM CDT — 43 knot peak wind at hayward.

DLH: 7 W Cloquet [Carlton Co, MN] public reports TSTM WND DMG at 09:12 AM CDT — large trees down near big lake.

DLH: Trego [Washburn Co, WI] law enforcement reports TSTM WND DMG at 10:25 AM CDT — trees down across washburn county…particularly in the trego area and just north of spooner.

DLH: Webster [Burnett Co, WI] trained spotter reports TSTM WND DMG at 10:00 AM CDT — in oakland township in burnett county. large oak tree blown down. 60 mph winds estimated. 1.4 inches of rain in 30 minutes.

DLH: 3 S Hayward [Sawyer Co, WI] trained spotter reports TSTM WND DMG at 10:38 AM CDT — trees down.

DLH: Siren [Burnett Co, WI] law enforcement reports TSTM WND DMG at 10:02 AM CDT — burnett county sheriff dispatch reports trees blown down across the county.

DLH: 5 Se Pine City [Pine Co, MN] law enforcement reports TSTM WND DMG at 09:32 AM CDT — tree branches down along highway 70.

DLH: Webb Lake [Burnett Co, WI] amateur radio reports HEAVY RAIN of M1.00 INCH at 10:31 AM CDT — 1 inch of rain in 20 minutes.

DLH: Cloquet [Carlton Co, MN] law enforcement reports TSTM WND DMG at 09:25 AM CDT — many tree limbs down…power lines down…and a few trees downed in and around the city of cloquet.

Update: 9am

Tornado Watch issued until 4pm includes metro and much of eastern Minnesota & western Wisconsin.

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(click for bigger image and cities)

We don’t say this often from the weather lab, but today is one of those days to keep a close eye on your plans and kids, and be ready to seek shelter if severe storms approach your location.

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All the necessary ingredients appear to be coming together for what could be a significant severe weather and tornado outbreak from the Twin Cities area south and east. Here are some of the parameters that are coming together today.

1) Deep tropical moisture:

Dew points are in the 70s and may approach Amazon Jungle levels near 80 degrees today.

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2) Unstable air mass:

A cold front and cooler air aloft will create rapidly rising air to generate storms easily today.

3) Strong wind shear:

Winds are turning with height in the atmosphere today. This means storms will rotate, and strong low level wind shear means that rotation can translate to ground level. That’s an ideal situation for producing tornadoes. SPC is concerned about the potential for strong (EF2 and higher) tornadoes in Minnesota and Wisconsin today.

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Helicity forecast today shows highest tornado threat from the Twin Cities south and east. (Image: Twisterdata.com)

4) Cold air aloft:

Violent updrafts within storms over 100 mph will carry hail high into the atmosphere today. There is the potential for golf ball to even baseball sized chunks of hail falling form the sky this afternoon.

5) Cold front approaching:

The timing of an approaching cold front means that storms may explode right overhead in the Twin Cities metro this today.

The bottom line is expect severe weather today. The greatest threat for tornadoes appears to be from the Twin Cities area south and east. This includes Mankato, Owatonna, Waseca, Northfield, Red Wing, Rochester, Albert Lea, La Crosse and Eau Claire.

Expect storms today to contain the potential for damaging winds, large hail, and flooding rains as they move through.

Here are some links to track storms today.

-Twin Cities NWS

-Twin Cities radar loop

-Latest warnings map

PH

  • bsimon

    what happened to the dampening affects of the light cloud cover this AM? Or is that just plain not enough to counteract the energy in the system? I ran from 5:40 to about 6:20 this AM; the humidity was shockingly high, making for a wet run, despite pleasant temps.

  • jeanette

    It would have been helpful to see this before I picked out my blouse and left the umbrella in the closet.

  • Paul Huttner

    Hi B:

    Yes, there is just too much insability to limit the (so far) non severe storms near the metro. If we get more sun today, things could get busy in a hurry this afternoon.

    Hi Jeanette:

    We’ve been talking about likely storms today since Monday. Hopefully that was plenty of lead time?

    PH

  • jeanette

    I’m most certainly the fool today!

  • Paul Huttner

    No way you’re a fool Jeanette. Here’s hoping you can walk between the raindops today!

    PH

  • Jill

    You may have explained this before, but what’s a “derecheo”?

    Thanks.

  • Bruce Sach

    Is there a site to show what the radar looked like before, during and after a storm comes through?