DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 211954
SWODY1
SPC AC 211952

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0252 PM CDT SUN OCT 21 2012

VALID 212000Z - 221200Z

...NO SVR TSTM AREAS FORECAST...

LITTLE CHANGE IN THINKING FROM THE PREVIOUS OUTLOOK. REMOVED SEVERE
WIND PROBABILITIES FROM THE MID MO VALLEY AS IT APPEARS ANY THREAT
SHOULD BE MAINLY ELEVATED HAIL. CONVECTION ALLOWING MODELS INDICATE
THE MOST LIKELY AREA OF DEVELOPMENT WILL BE OVER FAR NRN MO AND
IA...WITH HAIL POSSIBLE.

..JEWELL.. 10/21/2012

.PREV DISCUSSION... /ISSUED 1128 AM CDT SUN OCT 21 2012/

...SYNOPSIS...
MORNING WATER VAPOR IMAGERY SHOWS TWO UPPER FEATURES THAT WILL
AFFECT THE SRN/CNTRL UNITED STATES TODAY. THE FIRST IS A LOW
AMPLITUDE SHORTWAVE TROUGH CURRENTLY OVER NM...WHICH WILL TRACK NEWD
INTO THE CENTRAL PLAINS THIS EVENING. THE SECOND IS A STRONGER
SHORTWAVE TROUGH THAT WILL CROSS NORTHERN GULF OF CA WITH STRONGER
ASCENT SPREADING ACROSS PARTS OF NM AND WEST TX BY THIS EVENING AND
ESPECIALLY OVERNIGHT. BOTH THESE SYSTEMS WILL AID IN THE DEVELOPMENT
OF SCATTERED THUNDERSTORMS.

...NM/TX LATE...
SHORTWAVE TROUGH NOW CROSSING NRN GULF OF CA WILL TRANSLATE EAST
ACROSS NRN MEXICO AND THEN OVER THE UPPER RIO GRANDE VALLEY BY
TONIGHT. LIFT WITH THIS IMPULSE WILL ACT TO OVERCOME STRONG
INHIBITION AND AID SOME TSTM DEVELOPMENT AMIDST STRONG INSTABILITY.
SHEAR WILL ALSO BE SUFFICIENT FOR A FEW PERSISTENT UPDRAFTS WITH
SOME HAIL POSSIBLE. LATE NIGHT NATURE OF THE GREATEST STORM
DEVELOPMENT POTENTIAL...AND LIMITED AREAL EXTENT OF THIS POTENTIAL
BASED ON LATEST GUIDANCE...SUGGEST THAT SLGT RISK PROBABILITIES ARE
ON THE HIGH SIDE AND WILL LOWER OVERALL SEVERE PROBABILITIES TO NO
MORE THAN 5 PERCENT TO ACCOUNT FOR PERHAPS A COUPLE OF ISOLATED HAIL
EVENTS PRIOR TO MONDAY MORNING.

...MO/IA/IL...
PRONOUNCED MOISTURE ADVECTION ACROSS THE PLAINS THIS MORNING WAS
OCCURRING BENEATH A WELL-ESTABLISHED ELEVATED MIXED LAYER AND WILL
CONTRIBUTE TO A STEADY INCREASE IN MUCAPE OVER PARTS OF MO/IA/IL.
WHILE CAPPING IS FORECAST TO PREVENT DEEP CONVECTION THROUGH THE
DAY...MID LEVEL ASCENT ACCOMPANYING THE SHORTWAVE TROUGH MOVING NEWD
FROM THE SRN HIGH PLAINS...IN COMBINATION WITH INCREASING NOCTURNAL
WARM ADVECTION AND LOW LEVEL LIFT NEAR SFC LOW AND WARM
FRONT...SHOULD RESULT IN THE DEVELOPMENT OF SCATTERED SHOWERS AND
STORMS AFTER MIDNIGHT TONIGHT. A FEW OF THE STRONGER STORMS COULD
PRODUCE HAIL AND GUSTY WINDS. SIMILAR TO WEST TX...WITH GREATEST
SEVERE POTENTIAL OCCURRING LATE IN THE PERIOD AND EXPECTED TO BE
LIMITED IN AREAL EXTENT...ONLY LOW SEVERE PROBABILITIES APPEAR
WARRANTED WITH THIS OUTLOOK.

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