SPC Jul 27, 2012 0730 UTC Day 3 Severe Thunderstorm Outlook

SPC 0730Z Day 3 Outlook

DAY 3 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0228 AM CDT FRI JUL 27 2012

VALID 291200Z - 301200Z

...SYNOPSIS...
MODELS INDICATE LITTLE CHANGE TO THE LARGE-SCALE PATTERN FROM
SATURDAY INTO SUNDAY.  A SUBTROPICAL HIGH CENTER APPEARS LIKELY TO
REMAIN PROMINENT ACROSS THE SOUTH CENTRAL PLAINS...WITHIN BROADER
UPPER RIDGING ENCOMPASSING MOST AREAS FROM THE GREAT BASIN AND
ROCKIES INTO THE WESTERN GULF OF MEXICO.  IMPULSES PROGRESSING
AROUND THIS FEATURE ON SUNDAY COULD CONTRIBUTE TO CONVECTIVE
DEVELOPMENT ACROSS THE HIGHER TERRAIN...FROM THE SOUTHERN PLATEAU
INTO THE CENTRAL ROCKIES...AND OFF THE NORTHERN ROCKIES INTO THE
ADJACENT HIGH PLAINS...AS WELL AS ALONG THE PERIPHERY OF VERY WARM
ELEVATED MIXED LAYER AIR ADVECTING EASTWARD ACROSS MUCH OF THE 
PLAINS INTO THE MISSISSIPPI VALLEY.  SCATTERED THUNDERSTORMS WILL
ALSO REMAIN POSSIBLE BENEATH UPPER TROUGHING ALONG THE ATLANTIC
SEABOARD.  HOWEVER...CONVECTIVE POTENTIAL EAST OF THE ROCKIES IS
EXPECTED TO BE LIMITED BY SOMEWHAT MODEST MOISTURE LEVELS ACROSS
MOST AREAS.

...NORTHERN HIGH PLAINS...
A NORTHERLY AND EASTERLY LOW-LEVEL UPSLOPE FLOW BENEATH 20-30+ KT
WEST NORTHWESTERLY 500 MB FLOW WILL CONTRIBUTE TO SUFFICIENT SHEAR
FOR ORGANIZED CONVECTIVE DEVELOPMENT...INCLUDING ISOLATED
SUPERCELLS...GIVEN THE INITIATION OF AT LEAST SCATTERED STORMS
SUNDAY AFTERNOON.  SOME HAIL WILL BE POSSIBLE IN STRONGER STORMS
...BUT THE RISK FOR ISOLATED STRONG WIND GUSTS MAY BE MORE
PROMINENT...AS THE BOUNDARY LAYER BECOMES DEEPLY MIXED.

...LOWER MISSISSIPPI VALLEY...
SOUTH OF THE MORE STRONGLY CAPPING ELEVATED MIXED LAYER AIR...
MODELS SUGGEST THAT BOUNDARY LAYER MOISTURE WILL BE SUFFICIENT FOR
MODERATELY LARGE CAPE...WITH STRONG DAYTIME HEATING LIKELY.  AIDED
BY WEAK LOW-LEVEL WARM ADVECTION AND...PERHAPS...AN IMPULSE
CIRCULATING AROUND THE EASTERN PERIPHERY OF THE SUBTROPICAL HIGH
CENTER...STORM DEVELOPMENT APPEARS POSSIBLE ACROSS CENTRAL/EASTERN
ARKANSAS LATE SUNDAY AFTERNOON.  AIDED BY MODEST SHEAR BENEATH
NORTHERLY MID-LEVEL FLOW...AND THERMODYNAMIC PROFILES SUPPORTIVE OF
DOWNBURSTS AND SIGNIFICANT COLD POOL DEVELOPMENT...THE EVOLUTION OF
ONE OR TWO ORGANIZED SOUTHWARD PROPAGATING STORM CLUSTERS MAY NOT BE
OUT OF THE QUESTION...WITH THE RISK FOR POTENTIALLY DAMAGING WIND
GUSTS.

...ARIZONA...
MODELS ARE SUGGESTIVE THAT AT LEAST MODEST CAPE COULD CONTRIBUTE TO
CONVECTIVE DEVELOPMENT ACROSS THE HIGHER TERRAIN OF SOUTHEASTERN
ARIZONA SUNDAY AFTERNOON...IN THE PRESENCE OF FAVORABLE
WIND/VERTICAL SHEAR PROFILES FOR ORGANIZED PROPAGATION TOWARD THE
PHOENIX METROPOLITAN AREA.  IT IS STILL UNCLEAR WHETHER
MOISTURE/INSTABILITY OVER THE LOWER DESERTS WILL BE SUFFICIENT TO
MAINTAIN VIGOROUS CONVECTIVE DEVELOPMENT...BUT STRONG WIND GUSTS
WITH CONVECTIVE OUTFLOW COULD STILL REACH THIS AREA.

...NORTHEAST GEORGIA/WESTERN AND CENTRAL CAROLINAS...
SHEAR BENEATH WEAK TO MODEST NORTHWEST MID-LEVEL FLOW...COUPLED WITH
MODERATE DESTABILIZATION...COULD SUPPORT AND ENHANCE CONVECTIVE
DEVELOPMENT OFF THE SOUTHERN APPALACHIANS SUNDAY
AFTERNOON...PROVIDING AT LEAST LOW PROBABILITIES FOR SEVERE
WIND/HAIL.

..KERR.. 07/27/2012

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