Storm Watch: T-Storm/Flash Flood Watches include metro

1204 AM CDT WED JUL 27 2011

…FLASH FLOOD WATCH IN EFFECT UNTIL 10 AM CDT WEDNESDAY…

THE NATIONAL WEATHER SERVICE IN TWIN CITIES/CHANHASSEN HAS ISSUED

A

* FLASH FLOOD WATCH FOR PORTIONS OF CENTRAL MINNESOTA…EAST

CENTRAL MINNESOTA AND WEST CENTRAL MINNESOTA…INCLUDING THE

FOLLOWING AREAS…IN CENTRAL MINNESOTA…BENTON…KANDIYOHI…

MCLEOD…MEEKER…MORRISON…RENVILLE…SHERBURNE…SIBLEY…

STEARNS…TODD AND WRIGHT. IN EAST CENTRAL MINNESOTA…ANOKA…

CARVER…CHISAGO…DAKOTA…HENNEPIN…ISANTI…KANABEC…

MILLE LACS…RAMSEY…SCOTT AND WASHINGTON. IN WEST CENTRAL

MINNESOTA…CHIPPEWA…LAC QUI PARLE…SWIFT AND YELLOW

MEDICINE.

* UNTIL 10 AM CDT WEDNESDAY

* VERY HEAVY RAIN WITH THUNDERSTORMS COULD PRODUCE RAINFALL RATES

OF 1 TO 2 INCHES IN AN HOUR. RAINFALL TOTALS COULD EXCEED 3

INCHES IN A FEW SPOTS.

* FLASH FLOODING OF LOW LYING AND URBAN AREAS…INCLUDING

HIGHWAYS AND UNDERPASSES…AS WELL AS ALONG SMALL CREEKS AND

STREAMS…IS POSSIBLE OVERNIGHT.

Update 10:05pm

SPC has issued Severe Thunserstorms Watch #693 valid until 6am. This includes St. Cloud, Redwood Falls, Mankato and the Twin Cities metro area.

Expect storms in the greater Twin Cities metro generally anytime after midnight (NW metro) spreading east into most of the metro anytime after 1am.

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URGENT – IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 693

NWS STORM PREDICTION CENTER NORMAN OK

1005 PM CDT TUE JUL 26 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

CENTRAL AND SOUTHERN MINNESOTA

EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 1005 PM

UNTIL 600 AM CDT.

HAIL TO 1.5 INCHES IN DIAMETER…THUNDERSTORM WIND GUSTS TO 70

MPH…AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 75

STATUTE MILES EAST AND WEST OF A LINE FROM 10 MILES NORTHWEST OF

SAINT CLOUD MINNESOTA TO 20 MILES WEST SOUTHWEST OF MANKATO

MINNESOTA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).

REMEMBER…A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE

FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY

DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION…CONTINUE…WW 689…WW 690…WW

691…WW 692…

DISCUSSION…A LARGE HP SUPERCELL HAS RECENTLY MORPHED INTO A

CYCLONIC GYRE WITHIN THE PAST HOUR OVER FAR NERN SD. UPSCALE GROWTH INTO A LARGER CONVECTIVE SYSTEM APPEARS PROBABLE AS THE GYRE MERGES WITH DECAYING BOW OVER E-CNTRL SD. EXPECT MCS TO CONTINUE EWD ALONG IMMEDIATE COOL SIDE OF WARM FRONT…FORCED BY STRENGTHENING LOW-LEVEL WAA REGIME ATTENDANT TO NOCTURNAL LLJ. DAMAGING WINDS WILL REMAIN THE PRIMARY HAZARD WITH THESE STORMS.

AVIATION…A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 27030.

Update 7:45pm:

Tornado Watch #691 for weatern MN until 3am includes Alexandria, Fergus Falls and Morris.

1 1 1 1 1 tor tue.gif

URGENT – IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 691

NWS STORM PREDICTION CENTER NORMAN OK

735 PM CDT TUE JUL 26 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF

WEST-CENTRAL MINNESOTA

SOUTHEAST NORTH DAKOTA

NORTHEAST SOUTH DAKOTA

EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 735 PM

UNTIL 300 AM CDT.

TORNADOES…HAIL TO 2 INCHES IN DIAMETER…THUNDERSTORM WIND

GUSTS TO 70 MPH…AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 75 STATUTE

MILES EAST AND WEST OF A LINE FROM 30 MILES SOUTHEAST OF

WATERTOWN SOUTH DAKOTA TO 85 MILES NORTHWEST OF ALEXANDRIA

MINNESOTA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).

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.

OTHER WATCH INFORMATION…CONTINUE…WW 687…WW 688…WW

689…WW 690…

DISCUSSION…TSTMS CONTINUE TO DEVELOP THIS EVENING ALONG A COUPLE

OF W-E ORIENTED WARM FRONTAL SEGMENTS WITHIN INTENSIFYING LOW-LEVEL WAA REGIME. 00Z ABR SOUNDING IS QUITE REPRESENTATIVE OF THE AMBIENT ENVIRONMENT…FEATURING MLCAPE OF AROUND 3500 J/KG…45 KT OF

DEEP-LAYER SHEAR…A LOW LCL HEIGHT AND EFFECTIVE SRH OF AROUND 400

M2/S2. AS SUCH…A RISK FOR TORNADOES WILL EXIST WITH ANY STORMS

THAT CAN REMAIN MORE DISCRETE…IN ADDITION TO LARGE HAIL AND

DAMAGING WINDS.

AVIATION…TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

550. MEAN STORM MOTION VECTOR 26020.

…MEAD

Hazard Tornadoes EF2+ Tornadoes Likelihood Moderate

Severe Wind 65 kt+ Wind Moderate

Severe Hail 2″+ Hail Moderate

++++

We’re on storm watch in the weather lab tonight.

The next low pressure wave is heading east into Minnesota.

(Do we have a weather “target” on our backs or something?)

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A warm front is oozing north, and another warm moist unstable air mass is working in.

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Minnesota remains on the northern edge of the summer heat wave.

Expect scattered showers & T-Storms to increase through tonight, and slowly rumble east. Severe weather is most likely in the eastern Dakotas and western Minnesota tonight, with the threat for heavy rains for much of the area.

SPC has issued mesoscale discussions for the Dakotas, and watches may be issued shortly.

Storms will be bucking some drier air over eastern Minnesota where dew points have held in the 50s most of Tuesday, so eastward progress toward the metro may be slow tonight. Storm chances will increase after midnight and especially after 3am through 9am for the metro, eastern Minnesota and western Wisconsin.

You can track the storms eastward progress tonight below.

-SPC latest watches

-Latest Twin Cities radar loop

-Latest warnings from Twin Cities NWS

-Storm reports from Twin Cities NWS

PH

  • Curt

    Could you explain your post

    Mead

    EF2+ moderate…

    Is he a meteorologist predicting this?

  • daves

    Can someone give a definition of a “cyclonic gyre”? From “A LARGE HP SUPERCELL HAS RECENTLY MORPHED INTO A CYCLONIC GYRE WITHIN THE PAST HOUR OVER FAR NERN SD.”

    Does it have an “eye”?

    The term gyre seems largely applied to large scale circulations. How does it translate to mesoscale application?