

010 

WWUS20 KWNS 071334

SEL7

SPC WW 071334

ILZ000-MOZ000-071900-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 27

NWS STORM PREDICTION CENTER NORMAN OK

835 AM CDT TUE APR 7 2015



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  SOUTHWEST ILLINOIS

  SMALL PART OF EAST CENTRAL AND SOUTHEAST MISSOURI



* EFFECTIVE THIS TUESDAY MORNING AND AFTERNOON FROM 835 AM UNTIL

  200 PM CDT.



* PRIMARY THREATS INCLUDE...

  SCATTERED LARGE HAIL AND ISOLATED VERY LARGE HAIL EVENTS TO 2

    INCHES IN DIAMETER POSSIBLE

  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 40

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES SOUTH

SOUTHWEST OF SAINT LOUIS MISSOURI TO 25 MILES EAST OF CARBONDALE

ILLINOIS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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.



&&



DISCUSSION...CLUSTER OF SEVERE STORMS APPROACHING SAINT LOUIS SHOULD

PERSIST FOR ANOTHER FEW HOURS WILL MOVING ESEWD TOWARD SW IL.  A

FEED OF VERY STEEP MIDLEVEL LAPSE RATES AND MODERATE BUOYANCY WILL

MAINTAIN STRONG UPDRAFTS WITH CONTINUED POTENTIAL FOR LARGE

HAIL...IN A WIND PROFILE WITH SUFFICIENT DEEP-LAYER SHEAR FOR

ORGANIZED/SUPERCELL STRUCTURES.  SOME UPSCALE GROWTH OF THE CLUSTER

IS POSSIBLE INTO A SMALL MCS...AND ISOLATED DAMAGING GUSTS COULD

BECOME A CONCERN AS THE LOW LEVELS GRADUALLY DESTABILIZE THROUGH

MIDDAY/EARLY AFTERNOON IN ADVANCE OF THE STORMS.



AVIATION...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 500. MEAN STORM

MOTION VECTOR 30020.





...THOMPSON



433 

WWUS20 KWNS 071334

SEL7

SPC WW 071334

ILZ000-MOZ000-071900-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 27

NWS STORM PREDICTION CENTER NORMAN OK

835 AM CDT TUE APR 7 2015



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  SOUTHWEST ILLINOIS

  SMALL PART OF EAST CENTRAL AND SOUTHEAST MISSOURI



* EFFECTIVE THIS TUESDAY MORNING AND AFTERNOON FROM 835 AM UNTIL

  200 PM CDT.



* PRIMARY THREATS INCLUDE...

  SCATTERED LARGE HAIL AND ISOLATED VERY LARGE HAIL EVENTS TO 2

    INCHES IN DIAMETER POSSIBLE

  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 40

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES SOUTH

SOUTHWEST OF SAINT LOUIS MISSOURI TO 25 MILES EAST OF CARBONDALE

ILLINOIS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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.



&&



DISCUSSION...CLUSTER OF SEVERE STORMS APPROACHING SAINT LOUIS SHOULD

PERSIST FOR ANOTHER FEW HOURS WILL MOVING ESEWD TOWARD SW IL.  A

FEED OF VERY STEEP MIDLEVEL LAPSE RATES AND MODERATE BUOYANCY WILL

MAINTAIN STRONG UPDRAFTS WITH CONTINUED POTENTIAL FOR LARGE

HAIL...IN A WIND PROFILE WITH SUFFICIENT DEEP-LAYER SHEAR FOR

ORGANIZED/SUPERCELL STRUCTURES.  SOME UPSCALE GROWTH OF THE CLUSTER

IS POSSIBLE INTO A SMALL MCS...AND ISOLATED DAMAGING GUSTS COULD

BECOME A CONCERN AS THE LOW LEVELS GRADUALLY DESTABILIZE THROUGH

MIDDAY/EARLY AFTERNOON IN ADVANCE OF THE STORMS.



AVIATION...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 500. MEAN STORM

MOTION VECTOR 30020.





...THOMPSON

