DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 211225
SWODY1
SPC AC 211223

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0723 AM CDT SUN OCT 21 2012

VALID 211300Z - 221200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF WEST TX MAINLY
TONIGHT...

MORNING WATER VAPOR IMAGERY SHOWS TWO UPPER FEATURES THAT WILL
AFFECT THE CENTRAL UNITED STATES TODAY. THE FIRST IS A LOW
AMPLITUDE SHORTWAVE TROUGH CURRENTLY OVER NM...WHICH WILL TRACK
NORTHEASTWARD INTO THE CENTRAL PLAINS THIS EVENING. THE SECOND IS A
STRONGER SHORTWAVE TROUGH THAT WILL CROSS NORTHERN BAJA CALIFORNIA
AND AFFECT NM/WEST TX BY THIS EVENING. BOTH SYSTEMS WILL PROVIDE A
THREAT OF SCATTERED THUNDERSTORMS.

...NM/WEST TX...
STRONG DAYTIME HEATING IS EXPECTED ACROSS SOUTHEAST NM AND WEST TX
TODAY...RESULTING IN STEEP LOW LEVEL LAPSE RATES AND DEEP MIXING.
THE SURFACE DRYLINE IS EXPECTED TO DEVELOP AROUND THE LONGITUDE OF
MAF...WITH DRY/WINDY CONDITIONS TO THE WEST. INCREASING LARGE SCALE
FORCING COMBINED WITH DEEP MIXING IS EXPECTED TO RESULT IN SCATTERED
HIGH-BASED CONVECTION BY LATE AFTERNOON OVER SOUTHEAST NM AND
SOUTHWEST TX. THESE STORMS WILL APPROACH THE DRYLINE AROUND DUSK
AND MAY INTENSIFY TO SEVERE LEVELS. COVERAGE OF INTENSE STORMS IS
LIKELY TO BE SPARSE. HOWEVER...FORECAST SOUNDINGS SUGGEST
SUFFICIENT CAPE AND VERTICAL SHEAR FOR A RISK OF ROTATING STORMS
CAPABLE OF HAIL AND DAMAGING WINDS. THE PRIMARY THREAT IS LIKELY TO
BE 03-09Z IN THIS AREA.

...MO/IA/IL...
LOW LEVEL MOISTURE IS RAPIDLY INCREASING ACROSS THE PLAINS STATES
THIS MORNING WITH DEWPOINTS IN THE 70S AS FAR NORTH AS CENTRAL OK AT
12Z. CONTINUED MOISTENING THROUGH THE DAY WILL DESTABILIZE THE AIR
MASS OVER PARTS OF MO/IA...ALTHOUGH A CAPPING INVERSION SHOULD
INHIBIT DEEP CONVECTION. LATER TONIGHT...THE SHORTWAVE TROUGH OVER
NM WILL APPROACH AND RESULT IN ENHANCED LOW LEVEL WARM
ADVECTION/LIFT. MOST MODEL SOLUTION INDICATE THE LIKELIHOOD OF
SCATTERED SHOWERS AND THUNDERSTORMS /MAINLY AFTER MIDNIGHT/. A FEW
OF THE STRONGEST STORMS COULD PRODUCE HAIL AND GUSTY WINDS.
ORGANIZED SEVERE STORMS ARE NOT ANTICIPATED AT THIS TIME.

..HART/DEAN.. 10/21/2012

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