Severe Storm Outlook Narrative (AC)
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ACUS02 KWNS 011718
SWODY2
SPC AC 011717

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1217 PM CDT WED APR 01 2015

VALID 021200Z - 031200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE OZARKS OF SRN MO TO
THE LOWER OH VALLEY...

...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLGT RISK FROM
SERN KS TO THE OH VALLEY...

...SUMMARY...
THUNDERSTORMS...A FEW SEVERE...ARE FORECAST ACROSS THE OZARKS OF
SOUTHERN MISSOURI INTO THE LOWER OHIO VALLEY THURSDAY.  HAIL AND
LOCALLY DAMAGING WINDS WILL BE POSSIBLE WITH THE STRONGER STORMS.

...OZARKS TO LOWER OH VALLEY...

NRN STREAM SHORT-WAVE TROUGH WILL EJECT EWD ALONG THE INTERNATIONAL
BORDER INTO THE UPPER GREAT LAKES REGION EARLY IN THE DAY2 PERIOD.
THIS FEATURE SHOULD FORCE A SFC COLD FRONT INTO CNTRL IL...SWWD
ACROSS CNTRL MO BY EARLY AFTERNOON WHERE IT SHOULD BECOME THE FOCUS
FOR POTENTIALLY STRONG/SEVERE THUNDERSTORMS.

LATEST SHORT-RANGE MODEL GUIDANCE IS FAIRLY AGGRESSIVE IN ALLOWING A
SUBSTANTIAL PLUME OF WARM AIR AT 800MB TO ADVECT ACROSS SRN KS/NRN
OK INTO SRN MO AHEAD OF AFOREMENTIONED SFC FRONT.  THIS WARM LAYER
SHOULD PROVE EFFICIENT IN SUPPRESSING SFC-BASED CONVECTION ALONG THE
WIND SHIFT MUCH OF THE PERIOD...ESPECIALLY ACROSS MO/KS/OK/AR.
DOWNSTREAM...IT APPEARS BOUNDARY-LAYER HEATING...COMBINED WITH
FRONTAL ASCENT SHOULD INDUCE TSTM DEVELOPMENT BY EARLY-MID AFTERNOON
ACROSS IL/IND WITHIN STRONGLY SHEARED SWLY FLOW REGIME.  WHILE
FORECAST BUOYANCY IS NOT EXPECTED TO BE PARTICULARLY STRONG ACROSS
THIS REGION...ROTATING UPDRAFTS ARE CERTAINLY POSSIBLE WHERE FRONTAL
FORCING/STORM MERGERS DO NOT ENCOURAGE LINEAR CLUSTERING.  HAIL/
WIND ARE THE PRIMARY THREATS...ALTHOUGH AN ISOLATED TORNADO CAN NOT
BE RULED OUT ALONG ERN FRINGE OF STRONGER INSTABILITY WHERE CAP DOES
NOT SUPPRESS SFC-BASED CONVECTION.

ALONG THE TRAILING COLD FRONT ACROSS THE OZARKS...SFC-BASED
CONVECTION SHOULD STRUGGLE TO DEVELOP THROUGH 03/00Z...AS BOTH THE
NAM/GFS SUGGEST BOUNDARY LAYER MAY STRUGGLE TO WARM ENOUGH FOR
PARCELS TO REACH THEIR CONVECTIVE TEMPERATURES.  THUNDERSTORMS ARE
MORE LIKELY WITHIN POST-FRONTAL REGIME RESULTING IN PARCEL ASCENT
AOA 850MB.  STRONG CLOUD-LAYER SHEAR WILL SUPPORT ROTATING UPDRAFTS
AND LARGE HAIL IS CERTAINLY POSSIBLE.

...ELSEWHERE...

TSTM POTENTIAL IS CONDITIONAL ALONG DRY LINE ACROSS ERN OK/NCNTRL
TX.  LARGE SCALE FORCING IS EXPECTED TO REMAIN RATHER WEAK ACROSS
THIS REGION BUT STRONG HEATING COULD INDUCE A FEW
STORMS...ESPECIALLY ACROSS NCNTRL TX WHERE FORECAST SOUNDINGS FOR
KSEP AT 22Z EXHIBITS SBCAPE IN EXCESS OF 3000 J/KG.  IF STORMS FORM
ALONG THE DRY LINE LARGE HAIL WOULD BE A THREAT AND CONDITIONAL
SEVERE PROBS WOULD BE REQUIRED TO ACCOUNT FOR THIS THREAT.

ISOLATED TSTMS MAY ALSO DEVELOP ACROSS THE FL PENINSULA INTO THE
SERN U.S. AND INSTABILITY MAY PROVE SUFFICIENT FOR A FEW ROBUST
UPDRAFTS CAPABLE OF PRODUCING GUSTY WINDS OR SMALL HAIL.

..DARROW.. 04/01/2015



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