DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 131623
SWODY1
SPC AC 131621

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1121 AM CDT WED JUN 13 2012

VALID 131630Z - 141200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT
ACROSS THE NRN PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT
ACROSS THE SRN HIGH PLAINS...

...SYNOPSIS...

LARGE-SCALE PATTERN WILL REMAIN PROGRESSIVE THROUGH THE D1 PERIOD
WITH THE MOST PROMINENT FEATURE BEING SHORTWAVE TROUGH WHICH WILL
AMPLIFY WHILE TRANSLATING EWD FROM THE NRN INTERMOUNTAIN REGION TO
NRN PLAINS AND SRN CANADA PRAIRIE PROVINCES. ANOTHER POTENTIALLY
SALIENT FEATURE IS A MORE SUBTLE SHORTWAVE TROUGH EMBEDDED WITHIN
SUBTROPICAL AIR STREAM WHICH WILL TRANSLATE THROUGH SRN PARTS OF
AZ/NM AND NWRN MEXICO.

AT THE SURFACE...LEE CYCLOGENESIS IS FORECAST TODAY OVER ERN WY /IN
RESPONSE TO POLAR BRANCH SYSTEM MENTIONED ABOVE/ WITH THIS FEATURE
DEVELOPING EWD TO ERN SD BY 14/12Z. THIS LOW PRESSURE WILL BE
ATTENDED BY A COLD FRONT WHICH WILL ADVANCE EWD ACROSS THE NRN
PLAINS...AND SEWD INTO THE CNTRL HIGH PLAINS. A PRE-FRONTAL OR LEE
TROUGH IS EXPECTED TO STRENGTHEN TODAY FROM THE WY CYCLONE SWD
THROUGH ERN PARTS OF CO/NM.

...NRN PLAINS...

EML ORIGINATING FROM THE CNTRL ROCKIES WILL BE ADVECTED NEWD ACROSS
THE CNTRL PLAINS AND SD IN ADVANCE OF NRN HIGH PLAINS SHORTWAVE
TROUGH...RESULTING IN STEEPENING MIDLEVEL LAPSE RATES AND A
STRENGTHENING CAP. THIS PROCESS WILL OCCUR ABOVE A GRADUALLY
MOISTENING BOUNDARY LAYER WITH ENVIRONMENT BECOMING MODERATELY
UNSTABLE BY AFTERNOON AHEAD OF LEE LOW AND COLD FRONT WITH MLCAPE OF
1000-2000 J/KG.

INCREASED HEIGHT FALLS/FORCING FOR ASCENT COUPLED WITH LOW-LEVEL
UPSLOPE/CONVERGENT FLOW N/NW OF WRN SD SURFACE LOW ARE EXPECTED TO
FOSTER ISOLATED-WIDELY SCATTERED TSTMS BY LATE AFTERNOON/EARLY
EVENING ON THE EDGE OF STRONGER CAP FROM SERN MT/NWRN SD INTO WRN
ND. ADDITIONAL...ELEVATED STORMS ARE EXPECTED TO DEVELOP WITHIN
POST-FRONTAL ENVIRONMENT TONIGHT ACROSS NRN SD/SRN ND. IN THE
PRESENCE OF A VERTICALLY VEERING WIND PROFILE WITH AROUND 50 KT OF
DEEP WLY SHEAR...SETUP WILL FAVOR SUPERCELLS AS THE INITIAL STORM
MODE WITH POSSIBLE UPSCALE GROWTH INTO AN MCS OVERNIGHT. LARGE HAIL
AND DAMAGING WINDS WILL BE THE PRIMARY HAZARDS WITH THESE STORMS.

...SRN HIGH PLAINS INTO TRANS-PECOS REGION OF TX...

THE COMBINATION OF STRENGTHENING LEE TROUGH AND OUTFLOW FROM
DECAYING NOCTURNAL MCS OVER N-CNTRL/CNTRL TX WILL ENHANCE ELY/SELY
LOW-LEVEL WIND COMPONENT...ALLOWING FOR THE MAINTENANCE OF A MOIST
BOUNDARY LAYER ALONG THE HIGH PLAINS OF ERN NM/SWRN TX. THIS
MOISTURE WILL COINCIDE WITH STEEP MIDLEVEL LAPSE
RATES/EML...YIELDING AFTERNOON MLCAPE APPROACHING 1500-3000 J/KG.

CONVERGENCE ALONG LEE TROUGH AND/OR LIFT ALONG THE HIGH TERRAIN WILL
LIKELY BE AIDED BY EWD PROGRESSION OF SUBTROPICAL IMPULSE MENTIONED
ABOVE...FOSTERING ISOLATED-WIDELY SCATTERED TSTMS LATER THIS
AFTERNOON INTO EVENING FROM SERN CO INTO THE TRANS-PECOS REGION OF
TX. WHILE MID AND HIGH-LEVEL WIND FIELD HAS DIMINISHED FROM TUE
WITH PASSAGE OF LARGER-SCALE TROUGH TO THE E...SUFFICIENT VERTICAL
SHEAR STILL EXISTS TO SUPPORT SUPERCELLS AND MULTICELL STORM
CLUSTERS CAPABLE OF LARGE HAIL AND DAMAGING WINDS. THESE TSTMS MAY
MERGE INTO AN MCS TONIGHT WITH AN ISOLATED WIND/HAIL THREAT
PERSISTING ACROSS PORTIONS OF THE TX PNHDL INTO WRN/NWRN TX.

...RED RIVER VALLEY/ARKLATEX...

RADAR MOSAIC SHOWS A WELL-DEFINED MCV ASSOCIATED WITH DECAYED
NOCTURNAL MCS ALONG THE RED RIVER NEAR ADM. FORCING ASSOCIATED WITH
THIS FEATURE IS EXPECTED TO FOSTER AN INCREASE IN TSTMS TODAY FROM
THE VICINITY OF CIRCULATION CENTER OUTWARD RADIALLY ALONG EXISTING
OUTFLOW BOUNDARIES WHERE POCKETS OF STRONGER HEATING AND DEWPOINTS
IN THE 60S TO AROUND 70 F YIELD MODERATE AFTERNOON INSTABILITY.
RECENT VAD OBSERVATIONS FROM DYESS AFB AND FT. WORTH TX INDICATE A
BELT OF ENHANCED /25-35 KT/ MIDLEVEL FLOW WITHIN SRN SEMI-CIRCLE OF
CIRCULATION WHICH MAY CONTRIBUTE TO SUFFICIENT VERTICAL SHEAR FOR A
FEW SEVERE STORMS CAPABLE OF LOCALLY DAMAGING WINDS AND HAIL INTO
THIS EVENING.

..MEAD/ROGERS.. 06/13/2012

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