DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 112000
SWODY1
SPC AC 111958

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0258 PM CDT WED JUL 11 2012

VALID 112000Z - 121200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF GA AND SC...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF MT...WRN
ND...NRN WY AND ID...

SEVERAL CHANGES HAVE BEEN MADE TO THE OUTLOOK AT 20Z. THE FIRST
CHANGE IS TO ADD PARTS OF WRN AND CNTRL WY INTO THE 5 PERCENT WIND
AND HAIL PROBABILITY. STRONG THUNDERSTORMS HAVE DEVELOPED IN THE
HIGHER TERRAIN OF WRN WY AND WILL MOVE EWD ACROSS CNTRL WY WHERE
MESOANALYSIS SUGGEST LAPSE RATES EXCEED 9.0 C/KM. THIS COULD BE
ENOUGH FOR A FEW DAMAGING WIND GUSTS. THE SECOND CHANGE TO THE
OUTLOOK IS TO ADD PARTS OF NCNTRL AZ INTO THE 5 PERCENT WIND DAMAGE
PROBABILITY WHERE A FEW CELLS HAVE DEVELOPED OVER THE LAST HOUR. THE
THIRD CHANGE TO THE OUTLOOK IS TO ADD PARTS OF CNTRL OK...SE KS AND
WRN MO INTO THUNDER WHERE CELLS HAVE DEVELOPED ALONG AN AXIS OF
MODERATE INSTABILITY THIS AFTERNOON. OTHERWISE...THE ONLY CHANGES
ARE MINOR ADJUSTMENTS TO THE LINES.

..BROYLES.. 07/11/2012

.PREV DISCUSSION... /ISSUED 1126 AM CDT WED JUL 11 2012/

...MT/WY EAST TO NRN PLAINS...
WATER VAPOR IMAGERY AND VWP OBS DEPICTED A NARROW CORRIDOR OF
ENHANCED MID/UPPER FLOW OF 40-50KT FROM ID TO SWRN MT EARLY TODAY.
DCVA/LIFT ASSOCIATED WITH THIS SPEED MAX WAS LIKELY CONTRIBUTING TO
SCATTERED TSTMS AMIDST THE SMOKE PLUME IN VISIBLE IMAGERY FROM SRN
ID TO NRN WY. THIS DISTURBANCE IN CONCERT WITH HEATING OF THE DAY
AND OROGRAPHIC INFLUENCES WILL LIKELY RESULT IN AN INCREASE IN TSTMS
FROM THE CONTINENTAL DIVIDE EAST ACROSS NRN WY AND PORTIONS OF MT
THROUGH THE AFTERNOON. WARM AND DRY SUB-CLOUD LAYER BENEATH STEEP
LAPSE RATES SHOULD SUPPORT DAMAGING WIND GUST POTENTIAL AS THE
AFTERNOON PROGRESSES. STORMS SHOULD ALSO BE RELATIVELY ORGANIZED
GIVEN EFFECTIVE SHEAR IN THE CLOUD-BEARING LAYER ON THE ORDER OF
30-40KT. OVERALL STORM COVERAGE AND STORM PERSISTENCE
MAY...HOWEVER...REMAIN LIMITED GIVEN SUBTLE/FOCUSED FORCING...AND
LACK OF GREATER LOW LEVEL MOISTURE.

IF STORMS PERSIST INTO THE HIGH PLAINS GIVEN THE SHORT WAVE IMPULSE
MOVING EAST FROM THE ROCKIES...THE CHANCES FOR AT LEAST ISOLD SEVERE
WIND/HAIL EVENTS WILL INCREASE INTO TONIGHT FROM SERN MT INTO
ADJACENT AREAS OF THE WRN DAKOTAS. ANOTHER AREA OF AT LEAST ISOLATED
POTENTIAL WILL EXIST ALONG THE STRENGTHENING LEE/THERMAL TROUGH AXIS
ACROSS THE WRN DAKOTAS...AND INVOF WEAK COLD FRONT/LEE TROUGH
INTERSECTION OVER ND BY THIS EVENING. SHEAR AND INSTABILITY IN THESE
AREAS WILL MARGINALLY SUPPORT SEVERE WEATHER BUT TIME OF DAY AND
LACK OF STRONGER LARGE SCALE FORCING INTRODUCE UNCERTAINTIES
REGARDING OVERALL EXTENT OF THE SEVERE THREAT.

...SOUTHEAST...
RESIDUAL FRONTAL ZONE REMAINS STALLED ACROSS THE SOUTHEAST TODAY
FROM NRN AL TO SC. MORNING RAOBS FROM ATLANTA AND CHARLESTON SUGGEST
MINIMAL CHANGE IN AIRMASS CHARACTERISTICS OVER THE PAST 24 HOURS
DESPITE RELATIVELY WIDESPREAD CONVECTIVE OVERTURNING DURING THE
DIURNAL HEATING CYCLE YESTERDAY. ABUNDANT MOISTURE AND INTENSE
SURFACE HEATING WILL AGAIN CONTRIBUTE TO STRONG DESTABILIZATION
AMIDST 850-300MB MEAN WIND OF 10-15KT. PULSE AND A FEW MUTLICELLULAR
STORMS...PERHAPS MORE CONCENTRATED NEAR THE FRONT AND SEA BREEZE
BOUNDARIES...SHOULD AGAIN RESULT IN SCATTERED/LOCALIZED GUSTY WINDS.

...SOUTHWEST...
RICH MOISTURE AND INTENSE SURFACE HEATING AND OROGRAPHIC LIFT WILL
AID TSTM DEVELOPMENT LATER TODAY ACROSS THE MOUNTAINS OF AZ. A
MODEST INCREASE IN STORM-BEARING ELY FLOW IS NOTED TO THE SOUTH OF
THE GREAT BASIN ANTICYCLONE AND THIS COULD CONTRIBUTE TO STORMS
SPREADING OFF THE HIGHER TERRAIN TOWARD THE LOWER DESERTS. LACK OF
ANY IDENTIFIABLE SHORT WAVE IMPULSE WITHIN THE ANTICYCLONIC FLOW
DOES SUGGEST THAT STORM DEVELOPMENT MAY REMAIN QUITE SCATTERED.
HOWEVER...PATTERN AND POTENTIAL INSTABILITY WARRANT AT LEAST A LOW
PROBABILITY SEVERE TSTM WIND THREAT ACROSS THE REGION FOR LATER
TODAY.

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