Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 240553
SWODY2
SPC AC 240552

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1252 AM CDT TUE MAY 24 2016

VALID 251200Z - 261200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CNTRL AND
NRN PLAINS...LOWER TO MID MO VALLEY AND UPPER MS VALLEY...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE GREAT
PLAINS...ARKLATEX AND MID TO UPPER MS VALLEY OUTSIDE OF THE SLIGHT
RISK AREA...

...SUMMARY...
ISOLATED TO SCATTERED SEVERE THUNDERSTORMS WITH LARGE HAIL...WIND
DAMAGE AND PERHAPS A TORNADO OR TWO WILL BE POSSIBLE WEDNESDAY
AFTERNOON AND EVENING FROM THE CENTRAL PLAINS AND LOWER MISSOURI
VALLEY NORTHWARD INTO THE NORTHERN PLAINS AND UPPER MISSISSIPPI
VALLEY. MARGINALLY SEVERE THUNDERSTORMS WITH STRONG WIND GUSTS AND
HAIL WILL BE POSSIBLE ACROSS THE SOUTHERN PLAINS EXTENDING
NORTHEASTWARD INTO THE ARKLATEX AND MID MISSISSIPPI VALLEY.

...CNTRL AND NRN PLAINS/LOWER TO MID MO VALLEY/UPPER MS VALLEY...
SOUTHWEST MID-LEVEL FLOW WILL BE IN PLACE ON WEDNESDAY ACROSS THE
CNTRL U.S. AS A COUPLE OF SUBTLE SHORTWAVE TROUGHS MOVE NEWD THROUGH
THE FLOW. AT THE SFC...A LOW IS FORECAST TO DEEPEN ACROSS THE CNTRL
PLAINS WITH A DRYLINE EXTENDING SWD FROM THE LOW. A WARM FRONT MAY
EXTEND EWD FROM THE SFC LOW WITH THIS FEATURE MOVING NWD ACROSS THE
UPPER MIDWEST DURING THE DAY. THE WARM FRONT MAY BE A FOCUS FOR
SFC-BASED THUNDERSTORM DEVELOPMENT WEDNESDAY AFTERNOON FROM ERN NEB
ACROSS IA AND NWD INTO SE SD AND SRN MN. OTHER MORE ISOLATED
THUNDERSTORMS MAY DEVELOP ALONG THE DRYLINE IN CNTRL NEB EXTENDING
SWD INTO CNTRL KS.

CONCERNING THE SEVERE THREAT FOR WEDNESDAY AFTERNOON AND
EVENING...THE NAM...GFS AND ECMWF ARE IN GENERAL AGREEMENT...SHOWING
A QUALITY MOIST SECTOR FROM ERN KS AND MO NWD INTO ERN NEB AND IA
WHERE SFC DEWPOINTS SHOULD BE IN THE UPPER 60S TO NEAR 70 F. IN
RESPONSE...MODERATE INSTABILITY IS FORECAST TO BE IN PLACE BY MID TO
LATE AFTERNOON ACROSS MOST OF THE WARM SECTOR. MARGINALLY SEVERE
STORMS MAY DEVELOP ON THE ERN EDGE OF MODERATE INSTABILITY
ASSOCIATED WITH A SHORTWAVE TROUGH MOVING THROUGH THE UPPER MS
VALLEY. FURTHER WEST INTO THE MID MO VALLEY NEAR THE INSTABILITY
AXIS...FORECAST SOUNDINGS AT 00Z/THU SHOW 0-6 KM SHEAR IN THE 35 TO
45 KT RANGE OWING TO DIRECTIONAL SHEAR IN THE LOW-LEVELS AND SPEED
SHEAR IN THE MID-LEVELS. THIS ENVIRONMENT ALONG WITH STEEP LAPSE
RATES SHOULD BE FAVORABLE FOR SUPERCELL DEVELOPMENT WITH ISOLATED
LARGE HAIL AND A FEW DAMAGING WIND GUSTS. THE BEST POTENTIAL FOR
LARGE HAIL MAY BE WITH CELLS THAT DEVELOP NEAR THE DRYLINE WHERE
LAPSE RATES AND INSTABILITY SHOULD BE THE GREATEST. STORMS THAT
DEVELOP EWD ALONG THE WARM FRONT MAY ALSO ROTATE AND CONTAIN A
THREAT FOR HAIL AND ISOLATED WIND DAMAGE. A TORNADO OR TWO WILL ALSO
BE POSSIBLE WITH CELLS THAT CAN INTERACT WITH THE BOUNDARY
ESPECIALLY AS LOW-LEVEL STRENGTHENS DURING THE EARLY EVENING.

...SRN PLAINS/ARKLATEX/MID MS VALLEY...
WEST TO SOUTHWEST MID-LEVEL FLOW IS FORECAST ON WEDNESDAY FROM THE
SRN PLAINS INTO THE ARKLATEX AND MID MS VALLEY. AT THE SFC...A
DRYLINE IS FORECAST FROM WRN OK SWD INTO WCNTRL TX WITH A BROAD WARM
SECTOR EXTENDING FROM THE DRYLINE EWD TO THE MS VALLEY. LARGE-SCALE
ASCENT IS FORECAST TO BE WEAK ACROSS THE WARM SECTOR WHICH WILL KEEP
CONVECTIVE DEVELOPMENT ISOLATED IN MOST AREAS. ENHANCED LOW-LEVEL
CONVERGENCE ASSOCIATED WITH PRE-EXISTING BOUNDARIES ACROSS THE WARM
SECTOR SHOULD DETERMINE WHERE ISOLATED THUNDERSTORMS CAN DEVELOP.
MODERATE DEEP-LAYER SHEAR SHOULD BE IN PLACE ACROSS MOST OF THE WARM
SECTOR. FOR THIS REASON...ANY CELL THAT CAN BECOME ESTABLISHED IN
SPITE OF WEAK FORCING...MAY CONTAIN A POTENTIAL FOR HAIL AND STRONG
WIND GUSTS.

..BROYLES.. 05/24/2016

$$


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