DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 141943
SWODY1
SPC AC 141941

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0241 PM CDT TUE MAY 14 2013

VALID 142000Z - 151200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF SWRN TX...

SEVERAL MINOR CHANGES HAVE BEEN APPLIED TO THE 1630Z
OUTLOOK...NAMELY TO REMOVE SEVERE PROBS ACROSS THE UPPER GREAT LAKES
REGION AND TO MORE ACCURATELY ORIENT THE SEVERE PROBS ALONG THE
FRONT ACROSS THE CNTRL PLAINS. ADDITIONALLY...GREATEST SEVERE RISK
APPEARS TO BE JUST EAST OF THE BIG BEND REGION ALONG THE MEXICAN
BORDER WHERE LATE AFTERNOON TSTMS ARE EXPECTED TO SPREAD TOWARD THE
RIO GRANDE RIVER.

LARGE SCALE FORCING WILL REMAIN NORTH OF THE U.S. BORDER OVER
ONTARIO AND FOR THIS REASON...ALONG WITH POOR MOISTURE
CONTENT...HAVE OPTED TO LOWER THE SEVERE PROBS ACROSS THE UPPER
GREAT LAKES.

FARTHER SW...LATEST VIS IMAGERY DEPICTS A CORRIDOR OF
ENHANCED/DEEPENING BOUNDARY LAYER CU FROM ECNTRL CO...NEWD ACROSS
NWRN KS INTO CNTRL NEB. OTHER AGITATED MID LEVEL CU EXTENDS ACROSS
NWRN IA INTO SCNTRL NEB WHERE SFC TEMPERATURES HAVE SOARED ABOVE
100F. PW CONTENT IS NOT PARTICULARLY HIGH ALONG THIS CORRIDOR BUT
ISOLATED TSTMS HAVE EVOLVED ACROSS THE HIGHER TERRAIN OF CO AND
LOCALLY STRONG DOWNBURSTS MAY ACCOMPANY THE PSEUDO-STATIONARY
HEAVIER RAIN POCKETS.

EARLIER THOUGHTS REGARDING POTENTIAL SEVERE EVOLUTION ALONG THE
U.S./MEXICAN BORDER REMAIN.

..DARROW.. 05/14/2013

.PREV DISCUSSION... /ISSUED 1128 AM CDT TUE MAY 14 2013/

...SRN/WRN TX...
AN ELONGATED UPPER TROUGH AXIS FROM NRN CHIHUAHUA TO WEST TX IS
FORECAST TO MAINTAIN BACKGROUND ASCENT AS INTENSE DIURNAL HEATING
AND LOW LEVEL MOISTENING CONTRIBUTE TO STRONG DESTABILIZATION
THROUGH THE DAY. SHARPENING DRYLINE CIRCULATION...OROGRAPHIC LIFT
AND DEEP-LAYER ASCENT WITHIN/BENEATH LEFT FRONT QUADRANT OF
MID/UPPER JET STREAK WILL PROMOTE WIDELY SCATTERED AFTERNOON TSTMS
FROM BIG BEND AREA ACROSS THE SERRANIAS DEL BURRO RANGE OF NRN
MEXICO. STORMS SHOULD DEVELOP EAST INTO A MORE SUPPORTIVE
THERMODYNAMIC ENVIRONMENT WITH TIME. INITIALLY ISOLATED TO SCATTERED
CONVECTION MAY GROW A BIT UPSCALE AND POSE SOME THREAT OF LARGE HAIL
AND HIGH WINDS INTO THE EVENING. WHILE UNCERTAINTIES REMAIN WITH
REGARD TO OVERALL STORM COVERAGE AND MAGNITUDE OF SHEAR IN AREAS
WITH A HIGHER PROBABILITY FOR CONVECTION...LATEST STORM SCALE
WRF-ARW AND HRRR REMAIN CONSISTENT WITH EARLIER FORECASTS IN
DEVELOPING A SMALL MCS THROUGH THE EVENING FROM THE BIG BEND ESEWD
ACROSS THE MID/LOWER RIO GRANDE AND PERHAPS AS FAR NORTH AS THE HILL
COUNTRY. GIVEN THIS SCENARIO...A SMALL SLGT RISK AREA HAS BEEN
INTRODUCED FOR THE INCREASING CHANCE FOR SEVERE WEATHER THROUGH THIS
EVENING.

...WRN GREAT LAKES...
A LOW AMPLITUDE SHORT WAVE TROUGH WILL CONTINUE TO TRACK ESEWD ALONG
AND NORTH OF U.S./CANADA BORDER THROUGH TONIGHT. WEAK HEIGHT FALLS
WITH THIS SYSTEM WILL SUPPORT SOME INCREASE IN DEEP ASCENT ALONG AND
NORTH OF A WARM FRONT FROM THE ARROWHEAD OF MN SEWD ACROSS LOWER MI.
WHILE SHEAR AND LAPSE RATES IN THIS REGION WILL BE SUFFICIENT FOR AN
ISOLATED THREAT OF SEVERE STORMS ROOTED ABOVE A STABLE BOUNDARY
LAYER...LIMITED MOISTURE LEADING TO STRONG INHIBITION...ALONG WITH
ONLY MODEST LARGE SCALE ASCENT...WILL LIKELY PRECLUDE A MORE
WIDESPREAD THREAT OF ELEVATED CONVECTION. ONLY A LOW PROBABILITY
HAIL FORECAST WILL BE MAINTAINED ACROSS THE AREA THROUGH TONIGHT.

...CNTRL PLAINS...
THE COLD FRONT TRAILING SWWD FROM THE GREAT LAKES SYSTEM WILL
CONTINUE TO SETTLE INTO A VERY HOT AND DRY AIRMASS FROM NEB ENEWD TO
SWRN MN/NRN IA WHERE SFC TEMPERATURES IN SOME AREAS WILL EXCEED
100F. PRONOUNCED EML AND CONTINUED HEATING WILL CONTRIBUTE TO STRONG
DESTABILIZATION AND A DEEPLY MIXED BOUNDARY LAYER WELL OVER 10KFT
DEEP IN SOME PLACES. LACK OF STRONGER LARGE SCALE ASCENT AND ONLY
WEAK TO MODEST MID LEVEL FLOW WILL LIKELY PRECLUDE ANYTHING BUT
ISOLATED AND HIGH-BASED CONVECTIVE DEVELOPMENT THROUGH LATE
AFTERNOON/EARLY EVENING. HOWEVER...ANY CONVECTION THAT CAN
CONSOLIDATE IN THIS REGIME WILL POSE SOME THREAT FOR LOCALLY STRONG
TO DAMAGING WINDS.

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