Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 061632
SWODY1
SPC AC 061630

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT WED MAY 06 2015

VALID 061630Z - 071200Z

...THERE IS AN ENH RISK OF SVR TSTMS OVER PARTS OF CENTRAL KS AND
SOUTH-CENTRAL NEB...

...THERE IS AN ENH RISK OF SVR TSTMS OVER SOUTHWEST OK INTO WESTERN
NORTH TX...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CENTRAL AND
SOUTHERN PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS OVER PARTS OF THE MID ATLANTIC
REGION...

...THERE IS A MRGL RISK OF SVR TSTMS OVER PARTS OF THE CENTRAL AND
SOUTHERN PLAINS...

...SUMMARY...
ISOLATED TO SCATTERED SEVERE STORMS WILL BE POSSIBLE LATE THIS
AFTERNOON AND EVENING ACROSS PARTS OF THE CENTRAL AND SOUTHERN
PLAINS.

A LARGE UPPER TROUGH IS CENTERED OVER THE ROCKIES TODAY...WITH
MULTIPLE SHORTWAVE TROUGHS ROTATING THROUGH THE BASE OF THE LARGER
TROUGH AND AFFECTING THE SOUTHERN/CENTRAL PLAINS.  THE RESULT WILL
BE AN AXIS OF CONSIDERABLE CONDITIONAL SEVERE POTENTIAL TODAY.  THE
MAIN FORECAST PROBLEM IS FOCUSING PROBABILITIES ON AREAS WITH THE
HIGHEST POTENTIAL FOR CONVECTIVE INITIATION.

...NEB/KS...
THE MAIN SHORTWAVE TROUGH TODAY IS CURRENTLY OVER WESTERN KS...AND
WILL ROTATE NORTHEASTWARD INTO CENTRAL/EASTERN NEB AND
CENTRAL/EASTERN KS THIS AFTERNOON AND EVENING.  STRONG SOUTHERLY LOW
LEVEL WINDS OVER THIS REGION WILL MAINTAIN SURFACE DEWPOINTS IN THE
60S...WITH AFTERNOON HEATING YIELDING MLCAPE VALUES OF 1500-2000
J/KG.  12Z GUIDANCE IS CONSISTENT ON DEVELOPING ISOLATED
THUNDERSTORMS OVER NORTH CENTRAL KS BY MID AFTERNOON.  FORECAST
SOUNDINGS AHEAD OF THIS ACTIVITY SHOW SUBSTANTIAL LOW LEVEL AND DEEP
LAYER SHEAR FAVORABLE FOR SUPERCELLS CAPABLE OF VERY LARGE HAIL AND
POSSIBLY STRONG TORNADOES.  THIS ACTIVITY IS LIKELY TO TRACK INTO
SOUTH-CENTRAL NEB BY LATE AFTERNOON WITH A CONTINUED SIGNIFICANT
SEVERE THREAT.

FARTHER SOUTH IN KS ALONG THE DRYLINE...THE CONFIDENCE IN INITIATION
IS LESS THAN THE AFOREMENTIONED AREA...BUT STILL HIGH ENOUGH TO
INCLUDE AN ENHANCED SLIGHT RISK AREA.  STORMS HERE WILL LIKELY BE
MORE WIDELY SPACED...BUT FORECAST SOUNDINGS ARE VERY FAVORABLE FOR
VERY LARGE HAIL AND TORNADOES WITH ANY STORMS THAT FORM.

...NORTHWEST OK...
THE AREA WITH THE LOWEST CONFIDENCE IN ROBUST CONVECTIVE INITIATION
ALONG THE DRYLINE IS OVER NORTHWEST OK.  HOWEVER...VIRTUALLY ALL
MODELS AGREE ON A STRONG CAPE/SHEAR ENVIRONMENT BY LATE AFTERNOON
WITH LITTLE CAP.  ANY STORM THAT FORMS IN THIS REGION WOULD HAVE A
HIGH CONDITIONAL RISK OF SIGNIFICANT SEVERE WEATHER.  HOWEVER...
WILL MAINTAIN ONLY 5 PERCENT TORNADO AND 15 PERCENT HAIL
PROBABILITIES AT THIS TIME.

...SOUTHWEST OK INTO TX...
VISIBLE SATELLITE IMAGERY SHOWS STRONG HEATING OCCURRING OVER PARTS
OF WESTERN NORTH TX...WHERE DEWPOINTS ARE IN THE MID 60S.  THIS AREA
MAY BE FAR ENOUGH SOUTHWEST TO RECOVER FROM THE SUBSIDENCE
ASSOCIATED WITH THE SHORTWAVE OVER KS...WITH ANOTHER AREA OF HIGHER
CONFIDENCE IN CONVECTIVE INITIATION.  SUPERCELLS CAPABLE OF VERY
LARGE HAIL AND ISOLATED TORNADOES ARE EXPECTED TO OCCUR IN THIS
REGION DURING THE MID AFTERNOON THROUGH EVENING HOURS.

...MID ATLANTIC...
WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS
AFTERNOON IN A RATHER SMALL AREA OF SOUTHERN PA INTO NORTHERN VA.
THIS REGION IS ON THE SOUTHERN FRINGE OF STRONGER WESTERLIES...WITH
AFTERNOON MLCAPE VALUES AROUND 1000-1500 J/KG.  A FEW OF THE
STRONGER CELLS COULD PRODUCE GUSTY WINDS AND HAIL.

..HART/CONIGLIO.. 05/06/2015




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