Severe Storm Outlook Narrative (AC)
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ACUS01 KWNS 030052
SWODY1
SPC AC 030050

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0650 PM CST FRI DEC 02 2016

VALID 030100Z - 031200Z

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF SOUTH TEXAS...

...SUMMARY...
ISOLATED MARGINALLY SEVERE THUNDERSTORMS WITH STRONG WIND GUSTS AND
HAIL ARE POSSIBLE ACROSS PARTS OF SOUTH TEXAS THIS EVENING INTO
TONIGHT.

...SOUTH TEXAS...
THE LATEST WATER VAPOR IMAGERY SHOWS AN UPPER-LEVEL LOW NEAR THE
MEXICO AND ARIZONA BORDER WITH SOUTHWEST MID-LEVEL FLOW EXTENDING
ACROSS NORTHERN MEXICO INTO THE RIO GRANDE VALLEY.  AT THE SURFACE...
A LOW IS PRESENT OVER NORTHERN MEXICO WITH EASTERLY WINDS EXTENDING
EASTWARD FROM THE LOW ACROSS THE SOUTHERN THIRD OF TEXAS INTO THE
WESTERN GULF OF MEXICO.  SURFACE DEWPOINTS ARE IN THE 60S FAHRENHEIT
ACROSS SOUTH TEXAS WHERE THE RAP IS ANALYZING A SMALL POCKET OF
MODERATE INSTABILITY WITH MLCAPE ESTIMATED IN THE 1000 TO 1200 J/KG
RANGE.  THIS INSTABILITY SHOULD BE MAINTAINED FOR MUCH OF THIS
EVENING INTO THE OVERNIGHT PERIOD AS LIFT GRADUALLY INCREASES DUE TO
A DEVELOPING LOW-LEVEL JET IN SOUTHERN AND CENTRAL TEXAS. MODEL
FORECASTS INCLUDING THE HRRR...NAM AND ECMWF SUGGEST THAT CONVECTION
WILL INITIATE THIS EVENING ON THE WESTERN EDGE OF THE STRONGER
LOW-LEVEL FLOW ALONG THE RIO GRANDE RIVER NEAR AND TO THE SOUTH OF
LAREDO.  THIS CONVECTION IS FORECAST TO EXPAND EASTWARD ACROSS SOUTH
TEXAS DURING THE LATE EVENING AND OVERNIGHT PERIOD.  IN ADDITION TO
THE INSTABILITY...THE 00Z SOUNDINGS AT BROWNSVILLE AND CORPUS CHRISTI
SHOW MODERATE TO STRONG DEEP-LAYER SHEAR WHICH WOULD SUPPORT
ROTATION WITHIN THE BETTER ORGANIZED STORMS.  ANY STORM THAT CAN
EXHIBIT ROTATION WOULD HAVE POTENTIAL TO PRODUCE STRONG WIND GUSTS
AND HAIL.  THE MAIN LIMITING FACTOR WOULD BE THE POOR LAPSE RATES
THAT ARE EVIDENT ON THE 00Z SOUNDINGS ACROSS SOUTH TEXAS.  FOR THIS
REASON...THE SEVERE THREAT IS EXPECTED TO REMAIN MARGINAL THROUGH 12Z
SATURDAY.

..BROYLES.. 12/03/2016

$$



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