Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 061622
SWODY1
SPC AC 061620

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1120 AM CDT MON JUL 06 2015

VALID 061630Z - 071200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MIDWEST INTO CNTRL/SRN
PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS FROM THE UPPER GREAT LAKES INTO
SRN HIGH PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS OVER CNTRL/SRN FL...

...THERE IS A MRGL RISK OF SVR TSTMS OVER A PART OF THE MID
ATLANTIC...

...SUMMARY...
STRONG TO SEVERE THUNDERSTORMS MAY OCCUR THIS AFTERNOON AND EVENING
FROM THE SOUTHERN HIGH PLAINS NORTHEAST INTO THE UPPER GREAT LAKES.
A FEW STRONG TO SEVERE STORMS ALSO MAY OCCUR OVER FLORIDA AND THE
MID-ATLANTIC STATES.

...SYNOPSIS...

A CYCLONIC UPPER-AIR PATTERN WILL PREVAIL OVER MUCH OF CANADA AND
THE N-CNTRL CONUS WITH THE PRIMARY FEATURE OF INTEREST BEING AN
EMBEDDED SHORT-WAVE TROUGH AND ASSOCIATED BELT OF 40-50 KT MID-LEVEL
FLOW TRANSLATING FROM MANITOBA AND THE NRN PLAINS INTO ONTARIO AND
THE UPPER GREAT LAKES.  ELSEWHERE...A SHORT-WAVE TROUGH OVER THE
CNTRL APPALACHIANS WILL WEAKEN WHILE BEING ENTRAINED INTO THE RIDGE
BUILDING DOWNSTREAM FROM THE AFOREMENTIONED DISTURBANCE.

AT THE SURFACE...THE COLD FRONT RELATED TO THE CNTRL CANADA/N-CNTRL
U.S. TROUGH WILL PROGRESS EWD THROUGH THE UPPER GREAT LAKES WITH THE
TRAILING EXTENSION OF THIS BOUNDARY MOVING SEWD/SWD INTO THE OZARKS
AND SRN PLAINS.  A FRONTAL WAVE OVER E-CNTRL MN THIS MORNING MAY
UNDERGO SOME DEEPENING WHILE DEVELOPING THROUGH CNTRL WI TODAY.

...UPPER MIDWEST INTO SRN PLAINS THIS AFTERNOON AND EVENING...

VISIBLE SATELLITE AND MOSAIC RADAR DATA INDICATE THAT CONSIDERABLE
CLOUDINESS ASSOCIATED WITH ACTIVE CONVECTION WILL LIKELY LIMIT THE
POTENTIAL FOR AIR MASS DESTABILIZATION THIS AFTERNOON OVER THE UPPER
MIDWEST/UPPER GREAT LAKES REGION WHERE THE STRONGER VERTICAL SHEAR
AND FORCING FOR ASCENT WILL OVERSPREAD THE SURFACE COLD FRONT.
ISOLATED STRONG TO SEVERE STORMS --AND AN ASSOCIATED DAMAGING WIND
THREAT-- MAY EVOLVE LATE THIS MORNING INTO AFTERNOON ACROSS PORTIONS
OF CNTRL/ERN WI INTO NRN IL ALONG BOTH THE PRE-FRONTAL COLD POOL
CURRENTLY PROMOTING SHOWER AND TSTM DEVELOPMENT...AS WELL AS
POSSIBLY THE FRONT ITSELF.

FROM CNTRL IL INTO CNTRL KS/NRN OK...STRONGER DAYTIME HEATING
COUPLED WITH DEWPOINTS IN THE 70S WILL YIELD MODERATE TO STRONG
AFTERNOON INSTABILITY WITH MLCAPE VALUES OF 2000-3000+ J/KG.  THIS
INSTABILITY MAY FOSTER POTENTIALLY MORE VIGOROUS THUNDERSTORM
DEVELOPMENT LATER TODAY ALONG THE SYNOPTIC COLD FRONT AND/OR
PRE-FRONTAL OUTFLOW BOUNDARIES.  GENERALLY WEAK VERTICAL SHEAR
SHOULD LIMIT THE POTENTIAL FOR HIGHER-ORDER STORM MODES...THOUGH
MULTICELL CLUSTERS AND LINE SEGMENTS WILL REMAIN CAPABLE OF LOCALLY
DAMAGING WINDS AND SOME SEVERE HAIL INTO THIS EVENING.

...MID ATLANTIC THIS AFTERNOON...

VISIBLE SATELLITE IMAGERY REVEALS A WELL-DEFINED CYCLONIC
CIRCULATION OVER CNTRL VA WHICH WILL SHIFT NEWD TODAY.  WHILE
VERTICAL SHEAR WILL REMAIN RATHER WEAK...THE COMBINATION OF A MOIST
AND LEAST MODESTLY UNSTABLE AIR MASS...FORCING FOR ASCENT ASSOCIATED
WITH THIS FEATURE...AND A VERTICALLY VEERING WIND PROFILE MAY BE
SUFFICIENT TO SUPPORT A FEW WEAKLY ROTATING STORMS CAPABLE OF GUSTY
WINDS AND PERHAPS A BRIEF TORNADO.

..MEAD/MOSIER.. 07/06/2015



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