Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 271244
SWODY1
SPC AC 271242

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0742 AM CDT SAT AUG 27 2016

VALID 271300Z - 281200Z

...THERE IS A MRGL RISK OF SVR TSTMS PARTS OF IND/OH/LOWER MI...

...THERE IS A MRGL RISK OF SVR TSTMS ERN DAKOTAS/WRN MN VICINITY...

...SUMMARY...
ISOLATED DAMAGING WINDS WILL BE POSSIBLE ACROSS PARTS OF THE MIDWEST
INTO THIS AFTERNOON. ISOLATED SEVERE HAIL/WIND IS ANTICIPATED ACROSS
PARTS OF THE UPPER MIDWEST THIS AFTERNOON/EVENING.

...MIDWEST...
A SWATH OF SHOWERS AND EMBEDDED STORMS ARE ONGOING WITHIN A RICH PW
PLUME ACROSS PARTS OF IL/WI/IND/MI. A 1016 MB SURFACE CYCLONE OVER
SOUTHEAST IA IS EXPECTED TO TRACK NORTHEAST TOWARDS WEST-CENTRAL
LOWER MI BY EVENING WITH AN ASSOCIATED SURFACE WARM FRONT ADVANCING
NORTH FROM NORTHERN IND/CENTRAL OH INTO SOUTHERN LOWER MI.
HOWEVER...A LEAD CONVECTIVE CLUSTER ALONG THE IND/LOWER MI BORDER
COULD BE MAINTAINED THROUGH THE MORNING HOURS AND SUBSEQUENTLY SLOW
NORTHWARD ADVANCEMENT OF THE FRONT. MODEST DIABATIC HEATING
DOWNSTREAM COULD SUPPORT THIS CLUSTER INTENSIFYING BY LATE
MORNING/MIDDAY...YIELDING A PRIMARY RISK OF ISOLATED DAMAGING WINDS
AMID 25-30 KT DEEP SHEAR/LARGELY UNIDIRECTIONAL WIND PROFILES.
FARTHER NORTHWEST...A FEW MODELS SUGGEST DESTABILIZATION MAY OCCUR
IN THE WAKE OF THE MORNING ACTIVITY AND THIS COULD FOSTER A FEW
STORMS NEAR THE SURFACE CYCLONE LATE DAY. SHOULD THIS
OCCUR...MARGINAL INSTABILITY WILL PROBABLY LIMIT THE OVERALL SEVERE
RISK.

...UPPER MIDWEST...
PRONOUNCED SHORTWAVE TROUGH OVER THE CENTRAL DAKOTAS WILL MOVE EAST
INTO MINNESOTA BY LATE DAY. DESPITE THE NOTABLE
SHORTWAVE...LOW-LEVEL CONVERGENCE ALONG A SURFACE TROUGH IS EXPECTED
TO REMAIN WEAK. SCATTERED STORMS APPEAR MOST LIKELY TO PERSIST
WITHIN THE MID-LEVEL DCVA REGION ACROSS EASTERN ND AND NORTHWEST MN.
HERE...BUOYANCY AND DEEP SHEAR WILL BE MORE MARGINAL RELATIVE TO
FARTHER SOUTH ESPECIALLY WITH MORNING CONVECTION LIMITING
BOUNDARY-LAYER HEATING. FARTHER SOUTH...WHERE
THERMODYNAMIC/KINEMATIC PROFILES WOULD SUPPORT A RISK FOR
SUPERCELLS...LITTLE TO NO CONVECTION MAY OCCUR AS MID-LEVEL
SUBSIDENCE OVERSPREADS THE WEAK SURFACE BOUNDARY DURING THE
AFTERNOON. WILL MAINTAIN A CAT 1 RISK WITH THE EXPECTATION OF A FEW
MARGINALLY SEVERE STORMS NORTH AND CONDITIONAL POTENTIAL FOR A
SUPERCELL OR TWO SOUTH.

..GRAMS/COHEN.. 08/27/2016

$$



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