Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 300546
SWODY1
SPC AC 300544

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1244 AM CDT WED JUL 30 2014

VALID 301200Z - 311200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
ISOLATED SEVERE STORMS ARE POSSIBLE ACROSS PORTIONS OF OKLAHOMA AND
NORTH TEXAS THIS AFTERNOON INTO EVENING.

...SYNOPSIS...

A DEEP-LAYER CYCLONE WILL REMAIN ANCHORED OVER JAMES BAY WITH AN
ASSOCIATED LONG-WAVE TROUGH ENCOMPASSING THE ERN HALF OF NORTH
AMERICA. A NUMBER OF VORTICITY MAXIMA WILL PROGRESS THROUGH THIS
BROADER-SCALE REGIME...THE MOST SALIENT OF WHICH TO SEVERE TSTM
DEVELOPMENT IS A SHORT-WAVE TROUGH WHICH WILL TRANSLATE FROM THE
CNTRL HIGH PLAINS TO NEAR THE OK-AR BORDER BY 31/12Z. A WEAK SURFACE
LOW WILL ACCOMPANY THIS IMPULSE SEWD ALONG A BAROCLINIC ZONE WHICH
SHOULD BECOME WELL-DEFINED BY AFTERNOON ALONG THE RED RIVER VALLEY.

...SRN PLAINS THIS AFTERNOON AND EVENING...

SCATTERED SHOWERS AND TSTMS ARE EXPECTED TO BE ONGOING AT THE START
OF THE FORECAST PERIOD FROM WRN KS INTO PORTIONS OK. RESIDUAL CLOUD
COVER ASSOCIATED WITH THIS ACTIVITY WILL COMBINE WITH STRONG
BOUNDARY-LAYER HEATING OVER W-CNTRL TX TO YIELD A PRONOUNCED
BAROCLINIC ZONE BY AFTERNOON ALONG THE RED RIVER VALLEY. LOW-LEVEL
CONVERGENCE ALONG THIS BOUNDARY IN CONJUNCTION WITH DCVA ASSOCIATED
WITH THE MIGRATORY SHORT-WAVE TROUGH ARE EXPECTED TO FOSTER WIDELY
SCATTERED SURFACE-BASED TSTMS BY MID AFTERNOON WITH INITIAL
DEVELOPMENT MOST LIKELY OVER THE ERN TX PNHDL INTO WRN OK.

WHILE MIDLEVEL LAPSE RATES WILL REMAIN RELATIVELY WEAK...THE
PRESENCE OF BOUNDARY-LAYER DEWPOINTS IN THE MID TO UPPER 60S WILL
YIELD AFTERNOON MLCAPE APPROACHING 1000 J/KG. WHEN COUPLED WITH A
VERTICALLY VEERING WIND PROFILE WITH 35-45 KT OF EFFECTIVE BULK
SHEAR...THE SETUP WILL BE SUPPORTIVE OF SOME STORM
ORGANIZATION...INCLUDING POSSIBLE SUPERCELLS CAPABLE OF MARGINALLY
SEVERE HAIL...LOCALLY STRONG WIND GUSTS...AND PERHAPS A BRIEF
TORNADO. EXPECT THIS SEVERE WEATHER THREAT TO SPREAD ESEWD ALONG THE
RED RIVER VALLEY THROUGH THIS EVENING BEFORE DIMINISHING BY LATER
TONIGHT.

SHOULD LATER DATA INDICATE GREATER INSTABILITY THAN THAT CURRENTLY
FORECAST...AN UPGRADE TO A CATEGORICAL SLIGHT RISK MAY BECOME
NECESSARY IN SUBSEQUENT OUTLOOKS.

..MEAD/SMITH.. 07/30/2014



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