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Mesoscale Discussion 1663
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   MESOSCALE DISCUSSION 1663
   NWS STORM PREDICTION CENTER NORMAN OK
   0327 PM CDT THU SEP 08 2016

   AREAS AFFECTED...PORTIONS OF NORTHERN OKLAHOMA AND SOUTHERN KANSAS

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 082027Z - 082300Z

   PROBABILITY OF WATCH ISSUANCE...20 PERCENT

   SUMMARY...THE OKLAHOMA-KANSAS BORDER REGION AND VICINITY IS BEING
   MONITORED FOR AN INCREASING SVR-TSTM POTENTIAL THIS AFTERNOON...WITH
   THE SVR POTENTIAL LINGERING INTO THE EVENING HOURS. PRESENT
   INDICATIONS ARE THAT WW ISSUANCE IS UNLIKELY...THOUGH
   CONVECTIVE/ENVIRONMENTAL TRENDS WILL CONTINUE TO BE MONITORED.

   DISCUSSION...DIFFERENTIAL HEATING IN PROXIMITY TO A
   CLOUD-COVERAGE-GRADIENT ZONE EXTENDING W/E ACROSS SRN KS IS
   ENHANCING BAROCLINIC CIRCULATIONS. THIS IS FOSTERING THE RECENT
   TREND OF INCREASING VERTICAL DEVELOPMENT OF CUMULUS FIELDS ACROSS
   SRN KS -- FROM S OF DODGE CITY TO S OF WICHITA. MEANWHILE...
   ISENTROPIC ASCENT ATOP MODIFYING CONVECTIVE OUTFLOW FROM SERN KS
   THROUGH NERN OK IS ALSO PROVIDING A FOCUSED ZONE OF TOWERING
   CUMULUS/ISOLATED CONVECTIVE DEVELOPMENT. CONTINUED SFC HEATING
   AMIDST THE WARM/MOIST AIR MASS -- CHARACTERIZED BY DEWPOINTS IN THE
   LOWER 70S -- ON THE WARM SIDE OF THE DIFFERENTIAL-HEATING
   ZONE/OUTFLOW BOUNDARY -- IS SUPPORTING MLCAPE ON THE ORDER OF
   1500-2500 J/KG.

   THE LAMONT OK 17Z RAOB SAMPLED RELATIVELY NOTABLE MLCINH...THOUGH
   MODIFICATIONS TO THE THERMODYNAMIC PROFILE TO ACCOUNT FOR CURRENT
   SFC OBSERVATIONS SUGGEST THAT ANTECEDENT CAPPING HAS ERODED DURING
   THE PAST FEW HOURS. AS SUCH...THERE IS INCREASING CONCERN THAT
   SFC-BASED CONVECTIVE INITIATION WILL OCCUR ON A MORE WIDESPREAD
   BASIS IN THE 2130Z-0000Z TIME-FRAME. INITIAL ACTIVITY SHOULD BE
   FOCUSED IN PROXIMITY TO THE AFOREMENTIONED DIFFERENTIAL-HEATING
   ZONE/OUTFLOW BOUNDARY. CONVECTION SHOULD GENERALLY SPREAD EWD
   THROUGH THE LATE AFTERNOON/EVENING HOURS. HOWEVER...PREFERENTIAL
   DEVELOPMENT INTO THE WEAKLY CAPPED ENVIRONMENT FARTHER S INTO OTHER
   PARTS OF NRN OK WILL BE LIKELY INTO THE EVENING -- ESPECIALLY AS A
   SLY LLJ STRENGTHENS IN ASSOCIATION WITH GRADUAL NOCTURNAL DECOUPLING
   OF THE BOUNDARY LAYER.

   PRESENT INDICATIONS ARE THAT THE PRIMARY SVR HAZARD WILL BE ISOLATED
   SVR WIND GUSTS...ENHANCED BY WATER LOADING RELATED TO PW AROUND 2.17
   INCHES PER THE LAMONT RAOB. THIS RAOB INDICATES A MODEST 20-25 KT OF
   DEEP SHEAR...WHICH MAY SUPPORT LOCALIZED CONVECTIVE CLUSTERING --
   WITH LOCALIZED INSTANCES OF COLD-POOL AMALGAMATION ENCOURAGING THE
   RISK FOR STRONG WIND GUSTS. HOWEVER...WITH ONLY MODERATE MID-LEVEL
   LAPSE RATES IN PLACE...THE LACK OF STRONGER DEEP SHEAR...AND THE
   DEARTH OF LARGE-SCALE ASCENT...A MORE SUBSTANTIAL SVR RISK IS
   UNLIKELY. STRONGER DEEP SHEAR SHOULD REMAIN CONFINED TO AREAS
   FARTHER N. NEVERTHELESS...A FOCUSED CORRIDOR OF ISOLATED SVR RISK
   WILL LIKELY PERSIST THROUGH THE EVENING HOURS...AS THE NOCTURNALLY
   STRENGTHENING LLJ FOSTERS REGENERATING CONVECTION IN THE RELATIVELY
   HIGH-PW ENVIRONMENT.

   ..COHEN/HART.. 09/08/2016


   ATTN...WFO...TSA...ICT...OUN...DDC...AMA...

   LAT...LON   35859478 36039670 36379957 36650082 37250069 37519957
               37409694 37049542 36569465 35859478 

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