Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 011935
SWODY1
SPC AC 011933

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0233 PM CDT SUN MAY 01 2016

VALID 012000Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM WRN TN ACROSS KY AND INTO
SRN IN AND OH...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS MUCH OF THE OH VALLEY
INTO THE SERN STATES AND OVER SRN TX...

...SUMMARY...
A FEW SEVERE STORMS WIND LARGE HAIL AND DAMAGING WINDS ARE POSSIBLE
THIS AFTERNOON AND EVENING ACROSS THE OHIO VALLEY. MORE ISOLATED
STRONG TO SEVERE STORMS ARE ALSO POSSIBLE FROM PARTS OF THE
CAROLINAS AND TENNESSEE VALLEY TO THE GULF COAST AND SOUTH TEXAS.

...OH VALLEY INTO TN...
STORMS ARE INCREASING ALONG A WEAK SFC TROUGH FROM WRN KY INTO
TN...WHERE STRONG HEATING CONTINUES AND WITH RELATIVELY LONG
STRAIGHT HODOGRAPHS FAVORABLE FOR SPLITTING CELLS CAPABLE OF LARGE
HAIL. AS SUCH...HAVE EXPANDED THE SLIGHT RISK SWD. OTHER STORMS ARE
ALSO LIKELY LATER TODAY AS THE SHORTWAVE TROUGH CONTINUES EWD AND
INTERACTS WITH THE UNSTABLE AIR OVER INDIANA AND OHIO. LARGE HAIL
WILL CONTINUE TO BE THE PRIMARY THREAT.

...SRN TX...
A STALLED FRONT CURRENTLY EXTENDS FROM NEAR SERN TX INTO THE MIDDLE
RIO GRANDE VALLEY...WITH CONVERGENCE REINFORCED BY OUTFLOW OVER SWRN
LA. THE AREA WILL CONTINUE TO DESTABILIZE WITH A CONDITIONAL THREAT
OF LARGE HAIL AND STRONG WIND GUSTS SHOULD STORMS DEVELOP THIS
AFTERNOON. A FEW STORMS ARE ALSO POSSIBLE OVERNIGHT AS A SELY LOW
LEVEL JET INCREASES AND AID IN LIFT WARM ADVECTION.

..JEWELL.. 05/01/2016

.PREV DISCUSSION... /ISSUED 1117 AM CDT SUN MAY 01 2016/

...OH VALLEY THIS AFTERNOON/EVENING...
A WEAKENING MIDLEVEL LOW OVER NW MO/SW IA THIS MORNING WILL CONTINUE
TO DE-AMPLIFY INTO AN OPEN WAVE WHILE MOVING EWD TO IL/INDIANA BY
THIS EVENING...AND OH/WRN PA OVERNIGHT.  AN ASSOCIATED WEAK SURFACE
LOW WILL MOVE GENERALLY EWD ALONG A PRE-EXISTING BAROCLINIC ZONE
ACROSS IL/INDIANA/OH...IN ADVANCE OF THE MIDLEVEL TROUGH.  THE WARM
SECTOR S OF THE BOUNDARY IS CHARACTERIZED BY BOUNDARY LAYER
DEWPOINTS OF 60-64 F...AND SURFACE TEMPERATURES SHOULD WARM QUICKLY
INTO THE 75-80 F RANGE IN SUBSTANTIAL CLOUD BREAKS.  THE NET RESULT
WILL BE MODERATE BUOYANCY /MLCAPE APPROACHING 1500 J PER KG/ AND
LITTLE CONVECTIVE INHIBITION ALONG AND S OF THE BAROCLINIC ZONE THIS
AFTERNOON ACROSS THE OH VALLEY.

WIDELY SCATTERED THUNDERSTORM DEVELOPMENT IS EXPECTED EARLY THIS
AFTERNOON IN THE WARM SECTOR NEAR THE OH RIVER...PRIMARILY IN
RESPONSE TO DAYTIME HEATING/MIXING.  LOW-LEVEL FLOW/SHEAR WILL BE
WEAK IN THE WARM SECTOR...BUT DEEP-LAYER SHEAR AND STRAIGHT
HODOGRAPHS WILL BE SUFFICIENT FOR SOME ORGANIZED STORM STRUCTURES
AND POSSIBLY STORM SPLITS.  ISOLATED LARGE HAIL AND DAMAGING GUSTS
WILL BE THE MAIN CONCERNS AS THE CONVECTION SPREADS EWD TOWARD WV
THIS AFTERNOON.  FARTHER N...ANOTHER CLUSTER OF STORMS SHOULD ALSO
FORM ALONG THE FRONT AND JUST IN ADVANCE OF THE SURFACE LOW ACROSS
FROM SE IL INTO CENTRAL INDIANA LATE THIS AFTERNOON/EVENING.
ISOLATED SUPERCELLS WITH LARGE HAIL/DAMAGING WINDS WILL BE POSSIBLE
THROUGH LATE EVENING.

...SE STATES THIS AFTERNOON...
ONGOING CLUSTERS OF STORMS OVER LA/MS WILL CONTINUE TO DRIFT SWD
TOWARD THE NRN GULF SHELF WATERS...AND SPREAD EWD INTO AL THROUGH
THE AFTERNOON.  ISOLATED STRONG/DAMAGING WIND GUSTS WILL BE THE MAIN
THREAT WITH THESE STORMS.  OTHER STRONG STORMS MAY ALSO OCCUR ACROSS
NRN SC THIS AFTERNOON WHERE A LOOSE CLUSTER OF STORMS INTERACTS WITH
A SURFACE FRONT.

...S TX/RIO GRANDE VALLEY THROUGH TONIGHT...
A SURFACE FRONT WILL CONTINUE TO DRIFT SWD INTO S TX...BUT A STRONG
CAP IS PRESENT PER 12Z SOUNDINGS AND THE EXTENT OF THUNDERSTORM
DEVELOPMENT ALONG THE FRONT IS IN QUESTION.  IT IS MORE PROBABLE
THAT STORMS WILL FORM OVER THE MOUNTAINS W-SW OF DRT...BUT IF AND
HOW FAR THESE STORMS MAKE IT ACROSS THE RIO GRANDE IS NOT CLEAR.
WILL LEAVE LOW SEVERE PROBABILITIES TO COVER THE CONDITIONAL RISK
FOR BOTH SCENARIOS.

$$



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