DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 161943
SWODY1
SPC AC 161940

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0240 PM CDT WED OCT 16 2013

VALID 162000Z - 171200Z

...NO SVR TSTM AREAS FORECAST...

...20Z OUTLOOK UPDATE...

...GULF STATES...
A SOUTHEASTWARD ADVANCING BOUNDARY INTERSECTION OVER DEEP SOUTH
TEXAS WILL CONTINUE TO PROVIDE A FOCUS FOR CONVECTIVE DEVELOPMENT
ANOTHER COUPLE OF HOURS. HOWEVER...IT NOW APPEARS THAT
LOWER/MID-LEVEL INHIBITION PROBABLY WILL REMAIN SUFFICIENT TO
SUPPRESS THUNDERSTORM ACTIVITY...GIVEN THE ABSENCE OF SUBSTANTIVE
MID-LEVEL FORCING FOR UPWARD VERTICAL MOTION. IT STILL DOES NOT
APPEAR OUT OF THE QUESTION THAT...AS A SIGNIFICANT SHORT WAVE
IMPULSE TURNS EAST NORTHEAST OF THE SOUTHERN ROCKIES...THROUGH THE
MIDDLE MISSISSIPPI VALLEY LATER TONIGHT...THUNDERSTORM ACTIVITY
COULD STILL OCCUR ALONG THE FRONTAL ZONE ACROSS CENTRAL LOUISIANA
THROUGH PARTS OF CENTRAL MISSISSIPPI AND ALABAMA. HOWEVER...
PROBABILITIES APPEAR GENERALLY LOW.

...LOWER GREAT LAKES REGION...
A FEW LIGHTNING STRIKES HAVE BECOME EVIDENT WITH A NARROW BROKEN
FRONTAL/PRE-FRONTAL CONVECTIVE BAND EXTENDING AS FAR SOUTH AS THE
LAKE ERIE/NORTHEASTERN OHIO AREA. HOWEVER...STRONGER MID/UPPER
FORCING FOR UPWARD VERTICAL MOTION SPREADING ACROSS PARTS OF
SOUTHERN ONTARIO AND WESTERN QUEBEC IS EXPECTED TO SUPPORT THE BEST
CHANCE FOR THUNDERSTORM ACTIVITY THROUGH THE REMAINDER OF THE
AFTERNOON INTO EARLY EVENING.

..KERR.. 10/16/2013

.PREV DISCUSSION... /ISSUED 1132 AM CDT WED OCT 16 2013/

CORRECTED FOR NDFD GRAPHICS

...SYNOPSIS...

A BROAD CYCLONIC FLOW REGIME WILL BE MAINTAINED OVER THE CONUS WITH
A BELT OF ENHANCED MID AND UPPER-LEVEL FLOW STRETCHING FROM THE SRN
PLAINS TO NERN STATES. A COUPLE OF MORE DISTINCT VORTICITY MAXIMA
ARE EMBEDDED WITHIN THIS HIGH MOMENTUM AIR STREAM...ONE OF WHICH
WILL TRACK FROM THE UPPER GREAT LAKES TO SRN QUEBEC...AND ANOTHER
WHICH WILL TRANSLATE FROM THE FOUR CORNERS REGION TO MID MS
VALLEY.

IN THE LOW LEVELS...A COLD FRONT INITIALLY FROM SWRN ONTARIO/LOWER
GREAT LAKES TO TX GULF COAST WILL ADVANCE EWD/SEWD TO THE
APPALACHIANS AND CNTRL GULF COAST BY THU MORNING. THERE IS SOME
INDICATION IN LATEST MODEL GUIDANCE THAT A FRONTAL WAVE MAY FORM
OVER THE LOWER SABINE VALLEY LATER THIS AFTERNOON WITH THIS FEATURE
DEVELOPING NEWD TO NWRN AL BY 17/12Z.

...LOWER GREAT LAKES THIS AFTERNOON AND EVENING...

BOTH LARGE-SCALE FORCING FOR UPWARD VERTICAL MOTION AND VERTICAL
SHEAR WILL STRENGTHEN ACROSS THE REGION TODAY IN CONJUNCTION WITH
THE VORTICITY MAXIMUM MOVING THROUGH THE GREAT LAKES. AND WHILE
SOME BREAKS IN THE CLOUDS ALONG THE SURFACE COLD FRONT --AND WITHIN
THE MIDLEVEL DRY SLOT-- MAY YIELD POCKETS OF STRONGER HEATING...POOR
MIDLEVEL LAPSE RATES AND MARGINAL MOISTURE CONTENT WILL LIMIT THE
DEGREE OF AIR MASS DESTABILIZATION. A FEW LOW-TOPPED TSTMS WILL BE
POSSIBLE BY AFTERNOON...BUT THE PROSPECT FOR SEVERE WEATHER IS
EXPECTED TO BE LIMITED BY THE WEAK INSTABILITY.

...SRN TX TO LOWER MS VALLEY THIS AFTERNOON INTO TONIGHT...

12Z SOUNDINGS SHOW THE PRESENCE OF A SEASONABLY MOIST AIR MASS AHEAD
OF THE COLD FRONT WITH BOUNDARY LAYER DEWPOINTS IN THE UPPER 60S TO
LOWER 70S AND PW VALUES OF 1.6-2.0 INCHES. SIMILAR TO TUESDAY...A
SUB-TROPICAL MOISTURE PLUME --AND RESULTANT MULTI-LAYER CLOUDS--
ASSOCIATED WITH THE REMNANTS OF OCTAVE WILL LIMIT HEATING ALONG THE
COLD FRONT. MOREOVER...MIDLEVEL LAPSE RATES WERE OBSERVED TO BE
QUITE WEAK WHICH WILL LIMIT THE DEGREE OF AIR MASS DESTABILIZATION
LATER TODAY.

LATEST CONVECTION-ALLOWING MODEL GUIDANCE AND EARLY INDICATIONS IN
VISIBLE SATELLITE IMAGERY SUGGEST THAT TSTMS MAY EVOLVE THIS
AFTERNOON WITHIN NE-SW ORIENTED PRE-FRONTAL CONFLUENCE BANDS FROM
THE LOWER SABINE VALLEY TO CNTRL/SRN MS. THE POOR LAPSE RATES AND
RESULTING WEAK INSTABILITY ARE EXPECTED TO PRECLUDE A RISK FOR
SEVERE WEATHER.

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