Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 221816
SWODY2
SPC AC 221815

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0115 PM CDT Mon May 22 2017

Valid 231200Z - 241200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER SOUTH
TEXAS...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER
SOUTH-CENTRAL THROUGH SOUTHEAST TEXAS...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER A PORTION
OF THE GULF COASTAL STATES...

...SUMMARY...
A FEW STRONG STORMS REMAIN POSSIBLE TUESDAY FROM SOUTHERN PORTIONS
OF THE GULF COASTAL STATES INTO NORTHERN AND CENTRAL FLORIDA. OTHER
ISOLATED STRONG TO SEVERE STORMS MIGHT OCCUR OVER SOUTH TEXAS.

...Synopsis...
A BROAD SYNOPTIC UPPER LOW WILL PERSIST OVER THE EASTERN TWO THIRDS
OF THE COUNTRY TUESDAY. SEVERAL EMBEDDED VORTICITY MAXIMA WILL MOVE
THROUGH THIS FEATURE INCLUDING A MINOR IMPULSE FORECAST TO ADVANCE
THROUGH THE GULF COASTAL AREA, AND A MORE SIGNIFICANT SHORTWAVE
TROUGH THAT WILL ADVANCE SOUTH THROUGH THE SOUTHERN PLAINS. AT THE
SURFACE A QUASI-STATIONARY FRONT WILL STRETCH FROM THE CAROLINAS
THROUGH THE GULF COAST REGION AND INTO SOUTH TX EARLY TUESDAY. A
COLD FRONT INITIALLY FROM THE GREAT LAKES INTO SOUTHWEST TX WILL
CONTINUE SOUTHEAST. THE SOUTHWESTERN EXTENSION OF THIS FRONT WILL
MERGE WITH THE STATIONARY FRONT ACROSS SOUTH TX.

..SOUTH TEXAS...
STORMS MAY BE ONGOING ALONG AND JUST AHEAD OF A SOUTHEAST-MOVING
COLD FRONT ACROSS A PORTION OF WEST CENTRAL TX. THE COLD FRONT WILL
ENCOUNTER AN INCREASINGLY MOIST AND UNSTABLE ATMOSPHERE AS IT
APPROACHES SOUTH TX, AND POTENTIAL WILL EXIST FOR ADDITIONAL STORMS
TO REDEVELOP, ESPECIALLY AS THE COLD FRONT OVERTAKES THE
QUASI-STATIONARY FRONT. WINDS ABOVE 700 MB WILL STRENGTHEN WITH THE
APPROACH OF THE SOUTHEAST-ADVANCING SHORTWAVE TROUGH. WITH RICH
MOISTURE IN PLACE, MODERATE TO STRONG INSTABILITY IS EXPECTED AS THE
BOUNDARY LAYER DESTABILIZES DURING THE AFTERNOON. THIS ENVIRONMENT
WILL SUPPORT A THREAT FOR A FEW INSTANCES OF LARGE HAIL AND DAMAGING
WIND GUSTS AS STORMS DEVELOP DURING THE LATE AFTERNOON AND EVENING.

...SOUTHERN GEORGIA AND SOUTH CAROLINA THROUGH NORTHERN AND CENTRAL
FLORIDA...
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL LIKELY BE ONGOING ALONG
THE SOUTHERN PORTION OF THE GULF COASTAL STATES IN VICINITY OF THE
STALLED FRONT. THIS ACTIVITY WILL DEVELOP EAST DURING THE DAY IN
ASSOCIATION WITH THE PROGRESSIVE, LOW-AMPLITUDE SHORTWAVE TROUGH.  A
RESULT, INLAND DESTABILIZATION WILL REMAIN LIMITED EXCEPT POSSIBLY
ACROSS SOUTHERN GA, COASTAL SC AND NORTHERN THROUGH CENTRAL FL WHERE
ADVECTION OF RICH LOW-LEVEL MOISTURE AND DIABATIC HEATING WILL
CONTRIBUTE TO POTENTIAL FOR 1500 J/KG MLCAPE, IN THE PRESENCE OF
WEAK MID-LEVEL LAPSE RATES. A COUPLED LOW-MID LEVEL JET STRUCTURE
ACCOMPANYING THE SHORTWAVE TROUGH WILL RESULT IN SUFFICIENT VERTICAL
WIND PROFILES (30-40 KT 0-6 KM SHEAR) FOR A FEW ORGANIZED STORMS
WITH DAMAGING WIND THE MAIN THREAT. UNCERTAINTY REGARDING EXTENT OF
EARLY MORNING STORMS AND ITS IMPACT ON THE THERMODYNAMIC ENVIRONMENT
INCLUDES MORE THAN A MARGINAL CATEGORY AT THIS TIME, BUT A SLIGHT
RISK MIGHT BE INCLUDED IN FUTURE UPDATES.

..15_ows.. 05/22/2017

$$



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