Severe Storm Outlook Narrative (AC)
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000
ACUS02 KWNS 231730
SWODY2
SPC AC 231729

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1229 PM CDT SAT JUL 23 2016

VALID 241200Z - 251200Z

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PART OF THE UPPER GREAT
LAKES REGION INTO THE MIDWEST...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE CENTRAL HIGH
PLAINS...

...SUMMARY...
ISOLATED SEVERE STORMS WILL BE POSSIBLE ACROSS THE UPPER GREAT LAKES
AND MIDWEST REGIONS...ALONG WITH THE CENTRAL HIGH PLAINS...MAINLY
SUNDAY LATE AFTERNOON AND EVENING.

...SYNOPSIS...
A SHORTWAVE TROUGH AND ASSOCIATED SURFACE CYCLONE SHOULD TRACK EAST
ACROSS NORTHERN ONTARIO DURING THE PERIOD.  AN ATTENDANT SURFACE
COLD FRONT WILL PROGRESS EAST OVER THE UPPER GREAT LAKES...WITH THE
TRAILING PORTION BECOMING QUASI-STATIONARY ACROSS KS.

...UPPER GREAT LAKES...MIDWEST...
MODELS CONTINUE TO SUGGEST DECAYING CONVECTIVE CLUSTERS SHOULD BE
ONGOING AT 12Z/SUN IN THE VICINITY OF LAKE SUPERIOR TO LAKE
MICHIGAN.  REMNANTS OF THIS ACTIVITY WILL PERSIST EASTWARD ACROSS
LOWER MI AND ADJACENT STATES WITHIN A CONTINUED LOW-LEVEL WAA
REGIME.  GUIDANCE TENDS TO AGREE THAT THE DEGREE OF DESTABILIZATION
ON SUNDAY SOUTH OF ANY ONGOING CLUSTERS/CLOUDINESS AND AHEAD OF THE
APPROACHING COLD FRONT WILL BE STRONGER FROM THE MID MS VALLEY TO
NORTHERN INDIANA WITH RELATIVELY LOWER VALUES INTO LOWER MI.
THOUGH...INSTABILITY INTO THIS LATTER REGION SHOULD BE MODERATE.
MODELS APPEAR TO HAVE BETTER AGREEMENT WITH THE TIMING OF THE COLD
FRONT THROUGH THE UPPER GREAT LAKES TO THE MID MS VALLEY REGION.
DESPITE THE GREATER FORECAST CERTAINTY WITH THE AFOREMENTIONED
FACTORS...NEAR-NEUTRAL MID-LEVEL HEIGHT CHANGE THROUGH 25/00Z ALONG
THE FRONT...MODELS CONTINUE TO VARY WITH CONVECTIVE DEVELOPMENT
ALONG THE FRONT AND GREATEST CONFIDENCE SUGGESTS MINIMAL CONVECTIVE
QPF WILL OCCUR DURING PEAK HEATING.  THIS COMBINED WITH STRONGER
FLOW ALOFT/DEEP-LAYER SHEAR LAGGING THE COLD FRONT...THE WESTERN
EXTENT OF THE SEVERE THREAT REMAINS CONDITIONAL.

SUN EVENING/NIGHT...MODEL AGREEMENT SHOWS GREATER MIDLEVEL HEIGHT
FALLS OVERSPREADING THE WARM SECTOR AND YIELDING WIDELY SCATTERED
STORMS ALONG THE FRONT AND ANY REMNANT OUTFLOW BOUNDARIES FROM
SUNDAY MORNING CONVECTION.  THIS APPEARS MOST PROBABLE ACROSS PARTS
OF LOWER MI TO CENTRAL IL.  STRONGER MIDLEVEL WESTERLIES SHOULD
CONTINUE TO LAG BEHIND THE FRONT...BUT MODERATE DEEP SHEAR MIGHT
SUPPORT A MODESTLY ORGANIZED CLUSTER OR TWO NORTH.  LARGER BUOYANCY
WITH SOUTHWEST EXTENT SHOULD COMPENSATE FOR WEAKER SHEAR.  ISOLATED
SEVERE WIND/HAIL SHOULD BE THE MAIN HAZARDS.

...CENTRAL HIGH PLAINS...
MODEST UPSLOPE FLOW IS EXPECTED NORTH OF THE STALLED FRONT THAT WILL
LIKELY BISECT KS SUNDAY AFTERNOON. THIS SHOULD OCCUR BENEATH A BELT
OF WEAK TO MODERATE MIDLEVEL WESTERLIES PERIPHERALLY ASSOCIATED
WITH THE EQUATORWARD EXTENT OF THE ONTARIO SHORTWAVE TROUGH...AND
PERHAPS A WEAK MIDLEVEL IMPULSE TRACKING INTO WESTERN SD/NEB BY
25/00Z.  ISOLATED TO SCATTERED CONVECTION SHOULD FORM FROM LATE
SUNDAY AFTERNOON INTO THE EVENING ALONG THE LEE OF THE ROCKIES INTO
WESTERN KS.  AMID GENERALLY WEAK BUOYANCY AND EFFECTIVE BULK SHEAR
OF 35-40 KT...SETUP MAY FOSTER MULTICELL CLUSTERS AND EMBEDDED
WEAKLY ROTATING UPDRAFTS CAPABLE OF ISOLATED SEVERE WIND/HAIL.

..PETERS.. 07/23/2016

$$



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