DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 210540
SWODY1
SPC AC 210538

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1238 AM CDT SUN OCT 21 2012

VALID 211200Z - 221200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR PARTS OF THE
TRANS-PECOS/PERMIAN BASIN OF WRN TX TONIGHT...

...SYNOPSIS...
A SHORT WAVE TROUGH OFF THE BAJA CA COAST WILL DAMPEN SOMEWHAT AS IT
EJECTS E/NEWD INTO THE SRN HIGH PLAINS BY EARLY MON. A WEAK LEAD
IMPULSE WILL TRACK FROM NM TO THE MID-MO VALLEY. BROAD LOW-LEVEL
SWLYS WILL AID IN THE TRANSPORT OF RICH MOISTURE FROM THE SRN PLAINS
TOWARDS THE CORN BELT. A SURFACE COLD FRONT SHOULD BECOME
QUASI-STATIONARY ACROSS THE UPPER MS VALLEY TO THE CNTRL PLAINS THIS
EVENING. THIS BOUNDARY WILL INTERSECT A DRYLINE EXTENDING S/SWWD
INTO FAR WRN TX.

...TRANS-PECOS/PERMIAN BASIN OF WRN TX...
DIURNAL TSTM DEVELOPMENT SHOULD BE VERY ISOLATED OR NON-EXISTENT AS
THE REGION LIES IN BETWEEN THE TWO AFOREMENTIONED IMPULSES. BY
MID-EVENING...LARGE-SCALE ASCENT WILL INCREASE WITH APPROACH OF THE
BAJA CA SHORT WAVE TROUGH. THIS SHOULD YIELD ISOLATED TO WIDELY
SCATTERED ELEVATED TSTMS FORMING W OF THE DRYLINE...LIKELY
INTENSIFYING AS ACTIVITY DEVELOPS TOWARDS THE DRYLINE IN THE PERMIAN
BASIN OVERNIGHT. WITH APPROACH OF A 40-50 KT MID-LEVEL SPEED
MAX...DEEP SHEAR WILL BE FAVORABLE FOR A FEW SUPERCELLS PRIMARILY
PRODUCING LARGE HAIL.

...MID-MS/MO VALLEYS...
AN EXPANDING EML SHOULD PROVIDE A SUFFICIENT CAPPING INVERSION TO
LIMIT DIURNAL TSTM DEVELOPMENT ALONG THE DRYLINE AND FRONT TODAY. AS
A SWLY LLJ STRENGTHENS SUN EVENING...ROBUST ISENTROPIC LIFT SHOULD
YIELD CONVECTION INCREASING OVERNIGHT...PRIMARILY N/E OF THE MO
VALLEY. WITH A BROAD INFLUX OF RICH WRN GULF MOISTURE /CHARACTERIZED
BY 60S SURFACE DEW POINTS/...STEEP MID-LEVEL LAPSE RATES WILL
PROMOTE MODERATE BUOYANCY FOR SLIGHTLY ELEVATED PARCELS ROOTED JUST
ABOVE THE SURFACE. HOWEVER...EFFECTIVE SHEAR APPEARS TO REMAIN
MODEST FROM AROUND 20-30 KT. SETUP SHOULD YIELD A FEW MULTICELL
CLUSTERS CAPABLE OF ISOLATED MARGINALLY SEVERE HAIL AND PERHAPS
LOCALIZED DAMAGING WIND.

..GRAMS/MOSIER.. 10/21/2012

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