DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 231222
SWODY1
SPC AC 231220

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0720 AM CDT SUN SEP 23 2012

VALID 231300Z - 241200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
WITH THE EXCEPTION OF NM AND PARTS OF TX EWD ALONG THE GULF COAST
AND FL...MOST OF THE NATION EAST OF THE CONTINENTAL DIVIDE LIES
WITHIN THE CYCLONIC CIRCULATION AROUND A DEEP VERTICALLY STACKED LOW
CENTERED NORTH OF THE GREAT LAKES THIS MORNING. THE COLD FRONT
ASSOCIATED WITH THIS SYSTEM MARKS THE LEADING EDGE OF A COOLER/DRIER
AIRMASS AND WAS SITUATED OFF THE ERN SEABOARD BEFORE EXTENDING
INLAND AND WEST FROM GA TO TX...THEN NNWWD ACROSS THE HIGH PLAINS TO
THE FRONT RANGE OF THE ROCKIES. SFC HIGH PRESSURE WILL DEVELOP ESEWD
FROM THE PLAINS/MIDWEST WITH DRIER AIR INFILTRATING REMAINING AREAS
OF THE SOUTHEAST AND NRN FL THROUGH EARLY MONDAY. THE FRONT FROM THE
NRN GULF COAST NWWD INTO TX WILL RETREAT NWD AS A WARM FRONT THROUGH
EARLY MONDAY AS THE SFC HIGH SHIFTS EAST AND LOW LEVEL SLY FLOW
STRENGTHENS OVER THE PLAINS.

PERSISTENT SW/GREAT BASIN UPPER RIDGE WILL WEAKEN AS HEIGHT FALLS
WITH A DISTURBANCE CURRENTLY OVER WA/ORE SPREAD SEWD TOWARD THE FOUR
CORNERS AREA THROUGH EARLY MONDAY.

...ERN ORE TO GREAT BASIN...
TSTMS SHOULD INCREASE AS LIFT WITH THE ADVANCING MID/UPPER TROUGH
SPREADS ESEWD INTO A MOISTURE AXIS EMANATING FROM THE SUBTROPICAL
PACIFIC. DIURNAL HEATING AND OROGRAPHY MAY CONTRIBUTE TO A COUPLE OF
STRONGER STORMS WITH GUSTY WINDS DURING THE LATE AFTERNOON.
HOWEVER...MEAGER INSTABILITY SHOULD TEMPER ANY SEVERE STORM THREAT.

...SRN PLAINS...
SLOPED ASCENT ACROSS THE STALLED FRONT OVER TX/OK WAS LIKELY BEING
ENHANCED BY THE PASSAGE OF THE MID/UPPER JET ENTRANCE REGION AND
SUSTAINING A NARROW CORRIDOR OF WEAK ELEVATED STORMS FROM KS TO WRN
AR ATTM. THIS ACTIVITY IS FORECAST TO DIMINISH LATER THIS MORNING AS
DIURNAL WEAKENING OF ISENTROPIC LIFT OCCURS.

...TX/LA...
DAYTIME HEATING AND A VERY MOIST AIRMASS SOUTH OF THE STALLED
FRONT...FROM SOUTHEAST TX ACROSS SRN LA...WILL BOOST AFTERNOON
SBCAPE TO OVER 2000 J/KG. MODELS HAVE MIXED SIGNALS AS TO WHETHER
DEEP CONVECTION CAN INITIATE ON OR NEAR THE FRONT IN THESE AREAS.
REGION WILL LIE BENEATH WEAK BUT DIFFLUENT UPPER FLOW AND IT SEEMS
POSSIBLE THAT PERSISTENT LIFT NEAR/SOUTH OF THE FRONT MAY AID
ISOLATED STORM INITIATION. GIVEN LACK OF A MORE SUBSTANTIAL MODEL
SIGNAL...ANY DEVELOPMENT WILL LIKELY BE SPARSE AND POORLY ORGANIZED
SO SEVERE PROBABILITIES APPEAR UNWARRANTED AT THIS TIME. IF MODEL
CONSENSUS ON CONVECTIVE DEVELOPMENT STRENGTHENS...A LOW PROBABILITY
SEVERE HAIL/WIND AREA MAY BE INTRODUCED IN LATER OUTLOOKS.

...OZARKS LATE...
ELEVATED STORMS APPEAR POSSIBLE LATE TONIGHT INTO EARLY MONDAY
ACROSS AR AS SLY LOW LEVEL JET STRENGTHENS AND MOISTURE TRANSPORT
AND ISENTROPIC LIFT ARE ENHANCED IN THE PRESENCE OF STEEP MID LEVEL
LAPSE RATES. ISOLATED MARGINAL HAIL SEEMS POSSIBLE WITH THIS
ACTIVITY BUT OVERALL POTENTIAL AND TIMING/LOCATION UNCERTAINTIES
PRECLUDE THE ADDITION OF SEVERE PROBABILITIES AT THIS TIME.

..CARBIN/BOTHWELL.. 09/23/2012

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