SPC MD 1659

MD 1659 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR NORTHEAST AL…SOUTHEAST TN…AND NORTHERN GA

MESOSCALE DISCUSSION 1659
NWS STORM PREDICTION CENTER NORMAN OK
0121 PM CDT MON AUG 10 2015

AREAS AFFECTED...NORTHEAST AL...SOUTHEAST TN...AND NORTHERN GA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 101821Z - 102045Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED STRONG TO LOCALLY SEVERE WIND GUSTS WILL BE
POSSIBLE THIS AFTERNOON ACROSS NORTHEAST AL...SOUTHEAST TN AND
NORTHERN GA.  SEVERE THUNDERSTORM ISSUANCE IS UNLIKELY AT THIS
TIME...THOUGH CONVECTIVE TRENDS WILL BE MONITORED FOR GREATER
COVERAGE OF STRONGER STORMS THAT COULD WARRANT CONSIDERATION FOR A
WW.

DISCUSSION...MOSAIC RADAR IMAGERY INDICATED AN EAST-SOUTHEAST MOVING
MCV WHICH AT 1755Z WAS LOCATED NEAR THE NORTHEAST AL/TN BORDER. 
FORCING FOR ASCENT ATTENDANT TO THIS LOW-MID LEVEL FEATURE APPEARS
TO BE ENHANCING UPDRAFT STRENGTH PER TRENDS IN A GOES-R CLOUD-TOP
COOLING PRODUCT ACROSS THE EASTERN PORTION OF SOUTHERN MIDDLE TN
/COFFEE AND FRANKLIN COUNTIES/.  THIS ASCENT COMBINED WITH
CONVERGENCE/LIFT IN VICINITY OF AN EASTWARD-MOVING BOUNDARY WHICH
WAS ADVANCING INTO EASTERN TN...AND NORTHEAST TO CENTRAL AL...WILL
REMAIN A FOCUS FOR NEW STORMS.  THE ENVIRONMENT ACROSS THE
DISCUSSION AREA HAS BECOME MODERATELY UNSTABLE.  ALTHOUGH EFFECTIVE
BULK SHEAR IS EXPECTED TO REMAIN WEAK...35-40 KT SPEEDS IN THE 1-3
KM AGL LAYER PER HTX WSR-88D COULD ENHANCE THE POTENTIAL FOR LOCALLY
STRONG TO SEVERE WIND GUSTS WITHIN A DOWNSTREAM ENVIRONMENT
CHARACTERIZED BY STEEPENING SURFACE-3 KM LAPSE RATES AND DCAPE OF
1000-1400 J/KG.

..PETERS/HART.. 08/10/2015

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MRX...FFC...OHX...BMX...HUN...

LAT...LON   34838622 35568562 35328465 34958404 34348388 33938411
            33568465 33648561 33888692 34418649 34838622 

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from SPC Mesoscale Discussions http://1.usa.gov/1IzDtQu