Severe Weather Outlook for April 10, 2011

This page has information on possible thunderstorms, high winds, or tornadoes for the next 24 hours as provided by the Weather Service Storm Prediction Center. You can also view the possibility of severe weather for the next two days. The map and discussion are updated several times a day.

Refer to the text discussion below the map for descriptions of possible severe weather threats.

Hazardous Weather Forecast Maps:

Severe Weather Discussion:

000
ACUS01 KWNS 101956
SWODY1
SPC AC 101954

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0254 PM CDT SUN APR 10 2011

VALID 102000Z - 111200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS FAR SOUTHEASTERN
MINNESOTA...FAR NORTHEASTERN IOWA...MUCH OF WISCONSIN...AND PORTIONS
OF THE UPPER PENINSULA OF MICHIGAN...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER GREAT LAKES
REGION SWWD INTO NERN TX...

...UPPER GREAT LAKES REGION SWWD INTO NERN TX...
FORECAST REMAINS ON TRACK FOR A REGIONAL OUTBREAK OF SEVERE STORMS
-- INCLUDING THE POTENTIAL FOR ISOLATED STRONG TORNADOES -- ACROSS
THE UPPER MS VALLEY/WRN UPPER GREAT LAKES REGION.

STORMS HAVE BEEN SLOW TO INITIATE THIS AFTERNOON...AS CAPPING
CONTINUES TO HINDER DEVELOPMENT.  HOWEVER...A STRONG VORTICITY
MAXIMA/JET STREAK EVIDENT IN WV IMAGERY IS MOVING RAPIDLY NEWD
ACROSS KS INTO SERN NEB...AND SHOULD PROVIDE FAVORABLE ASCENT --
FOCUSED ALONG THE SURFACE COLD FRONT ACROSS SERN MN/CENTRAL IA --
FOR CAP EROSION AND SUBSEQUENT CONVECTIVE INITIATION.

ONCE STORMS INITIATE...MODERATELY-UNSTABLE AIRMASS COMBINED WITH
VERY STRONG/FAVORABLE DEEP-LAYER WIND FIELD WILL SUPPORT RAPID
SUPERCELL EVOLUTION...AND SUBSEQUENT THREATS FOR VERY LARGE
HAIL...DAMAGING WINDS...AND TORNADOES.  STORMS SHOULD EVENTUALLY
SHIFT ACROSS WI INTO UPPER MI...AND ACROSS LAKE MI INTO THE LOWER
PENINSULA WITH CONTINUED THREATS FOR DAMAGING WINDS...HAIL...AND AN
ISOLATED TORNADO.

STORMS SHOULD ALSO DEVELOP -- IN A GENERALLY MORE LINEAR FASHION --
SWWD ALONG THE FRONT...AND THEN SHIFT STEADILY EWD WITH TIME ACROSS
MO/ERN OK/AR AND NERN TX.  OVERNIGHT...THREAT FOR DAMAGING WINDS
SHOULD ALSO SPREAD ACROSS THE MIDWEST...WANING SLOWLY AS THE
ATMOSPHERE DIURNALLY STABILIZES.

..GOSS.. 04/10/2011

.PREV DISCUSSION... /ISSUED 1118 AM CDT SUN APR 10 2011/

...CONDITIONS STILL APPEAR FAVORABLE FOR A REGIONAL OUTBREAK OF
SEVERE THUNDERSTORMS INCLUDING POTENTIAL FOR STRONG TORNADOES LATER
THIS AFTERNOON AND EVENING OVER PORTIONS OF UPPER MISSISSIPPI VALLEY
AND ADJACENT WESTERN GREAT LAKES...

DEEP WRN UPPER TROUGH NOW MOVING BODILY EWD INTO PLAINS WITH A VERY
STRONG...100-130 KT...MID/UPR JET APPROACHING THE UPPER MS VALLEY
FROM THE CENTRAL PLAINS. THIS WILL PROVIDE THE LARGE SCALE ASCENT
AND SHEAR TO DRIVE A SEVERE THUNDERSTORM OUTBREAK ONCE SURFACE BASED
CONVECTION IS ABLE TO INITIATE.

WITH THE SURFACE LOW SWRN MN DEEPENING NEWD ACROSS LAKE SUPERIOR BY
TONIGHT...STRONG SLY LOW LEVEL JET WILL CONTINUE SPREADING MOISTURE
NWD ACROSS WI INTO WRN GREAT LAKES. A PRONOUNCED EML WITH STEEP
LAPSE RATES PREVAILS ABOVE THE MOIST BOUNDARY LAYER AND WILL AID IN
VERY RAPID THUNDERSTORM DEVELOPMENT VICINITY OF THE COLD FRONT WHICH
BY MID AFTERNOON WILL EXTEND SWD FROM SURFACE LOW EXPECTED TO BE
BETWEEN DLH AND MSP INTO NERN IA.

SUPERCELL THUNDERSTORMS SHOULD DEVELOP RAPIDLY AS SURFACE TEMPS RISE
INTO THE LOW 80S BY MID AFTERNOON IN SERN MN/ERN IA WHERE MLCAPES
AOA 2000 J/KG WILL BE IN PLACE. FORECAST SOUNDINGS AT THE TIME OF
EXPECTED INITIATION SHOW EFFECTIVE HELICITY VALUES OF 250-400 MS/S2
AND VERY STRONG DEEP LAYER VERTICAL SHEAR.

SUPERCELLS WILL BE THE MODE OF THE DAY ALONG WITH POTENTIAL FOR VERY
LARGE HAIL AND TORNADOES.  A COUPLE LONG LIVED SUPERCELLS ARE LIKELY
LATER THIS AFTERNOON AND EVENING ACROSS WI WITH THE THREAT FOR
STRONG...LONG TRACK TORNADOES.  STORMS WILL MOVE VERY FAST...IN
EXCESS OF 50KT...GIVEN THE STRENGTH OF THE WIND FIELDS ALOFT.

SUPERCELLS ALONG WITH A TORNADO THREAT COULD SPREAD AS FAR N AS
PORTIONS OF THE WRN UP OF MI PRIOR TO ENCOUNTERING COOLER/STABLE
BOUNDARY LAYER THIS EVENING.

HIGH RES MODELS SUGGEST THAT STORMS EVOLVE INTO A FORWARD
PROPAGATING MCS ACROSS THE UP OF MI LATE EVENING DRIVEN BY THE
INTENSIFYING WIND FIELDS AS SURFACE LOW CONTINUES TO DEEPEN NEWD
ACROSS LAKE SUPERIOR. THUS HAVE RAISED THE WIND DAMAGE PROBS THIS
AREA...EVEN THOUGH STORMS BY THEN COULD BE SOMEWHAT ELEVATED.



...MID MS VALLEY TO ARKLATEX...
IT WILL TAKE MUCH OF THE AFTERNOON TO ERODE THE CAP ALONG THE SWD
EXTENSION OF THE COLD FRONT/DRY LINE. HOWEVER THE STRONG DEEP LAYER
SHEAR WITH THE ADVANCING UPPER TROUGH COUPLED WITH THE STEEP
EML...SUPPORT SEVERE THUNDERSTORMS ONCE SURFACE INITIATION OCCURS.
AGAIN SUPERCELLS EXPECTED TO BE THE EARLY MODE WITH LARGE
HAIL/DAMAGING WINDS AND ISOLATED TORNADOES POSSIBLE.  DURING THE
LATE EVENING TRANSITION TO A MORE LINEAR MODE LIKELY WITH A
CONTINUED SEVERE THREAT.