DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 161249
SWODY1
SPC AC 161247

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0747 AM CDT WED OCT 16 2013

VALID 161300Z - 171200Z

...NO SVR TSTM AREAS FORECAST...

...WRN GULF COAST/LOWER MS VALLEY AND LOWER GREAT LAKES REGION...
A COUPLE OF SHORTWAVE TROUGHS WILL PROGRESS NEWD WITHIN A CYCLONIC
FLOW REGIME EXTENDING FROM THE SWRN TO THE NORTHEAST STATES. THE
LEAD TROUGH WILL MOVE FROM THE UPPER GREAT LAKES TO SRN QUEBEC...
WHILE A FOUR CORNERS TROUGH TRACKS ACROSS THE SRN/CENTRAL PLAINS TO
THE MID MS VALLEY BY 12Z THU. EARLY MORNING SURFACE ANALYSIS SHOWED
AN AREA OF LOW PRESSURE CENTERED OVER ERN UPPER MI WITH THIS FEATURE
EXPECTED TO TRACK TOWARD SRN QUEBEC CONCURRENT WITH THE ATTENDANT
UPPER GREAT LAKES SYSTEM. A COLD FRONT TRAILED SWWD FROM THIS LOW
THROUGH THE LOWER OH VALLEY TO TX GULF COAST. THIS BOUNDARY WILL
ADVANCE EWD ACROSS THE OH/TN VALLEYS AND INTO PA/NY...WITH SLOWER
MOVEMENT OF THE SRN PORTION OF THE FRONT ACROSS THE LOWER MS VALLEY
AND INTO THE FAR WRN GULF OF MEXICO.

SATELLITE IMAGERY SHOWED A PLUME OF SUB-TROPICAL MOISTURE EXTENDING
ALONG AND AHEAD OF THE COLD FRONT FROM NERN MEXICO AND S TX TO THE
LOWER GREAT LAKES. 12Z SOUNDINGS INDICATED PW VALUES WITHIN THIS
MOISTURE PLUME WERE GREATER THAN 1 INCH IN THE LOWER GREAT LAKES/
UPPER OH VALLEY...AND RANGED FROM 1.75 TO 2 INCHES FROM THE LOWER MS
VALLEY TO THE TX COAST. DESPITE THIS AVAILABLE MOISTURE...WHICH
WILL AID IN ADDITIONAL CONVECTIVE SHOWERS INVOF THE FRONT AND WITHIN
THE POST-FRONTAL REGION...WEAK MIDLEVEL LAPSE RATES WILL RESULT IN
FAIRLY WEAK INSTABILITY AND UPDRAFT STRENGTHS. FORECAST SOUNDINGS
SUGGEST THE GREATEST POTENTIAL FOR TSTMS TODAY WILL BE ACROSS S-SERN
TX AND THE LOWER MS VALLEY...THOUGH WEAK FORCING ALOFT AND WEAKENING
CONVERGENCE ALONG THE FRONT SHOULD RESULT IN SPORADIC TSTM COVERAGE.
FORCING FOR ASCENT WILL TEND TO BE GREATER OVER THE LOWER GREAT
LAKES WITH THE PROGRESSIVE SHORTWAVE TROUGH...BUT EQUILIBRIUM
TEMPERATURES MAY NOT BECOME COLD ENOUGH FOR CHARGE SEPARATION/
LIGHTNING PRODUCTION. ALTHOUGH EFFECTIVE BULK SHEAR WILL BE
SUFFICIENT FOR ORGANIZED STORMS ACROSS THE TWO GENERAL TSTM AREAS
TODAY...WEAK INSTABILITY/LAPSE RATES WILL PRECLUDE A SEVERE WEATHER
THREAT.

..PETERS/SMITH.. 10/16/2013

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