[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 130623
SWOMCD
SPC MCD 130623
TNZ000-MSZ000-ARZ000-OKZ000-130930-

MESOSCALE DISCUSSION 1279
NWS STORM PREDICTION CENTER NORMAN OK
0123 AM CDT TUE JUL 13 2010

AREAS AFFECTED...PORTIONS CENTRAL/NRN AR...EXTREME ERN OK...SWRN
TN...NWRN MS.

CONCERNING...HEAVY RAINFALL

VALID 130623Z - 130930Z

ORGANIZING MCS WITH EMBEDDED HEAVY-RAIN CORES...INITIALLY BECOMING
MORE DENSE EXPANDING ACROSS NRN AR OZARKS...IS EXPECTED TO MOVE
ESEWD TO WRN TN...SIMULTANEOUSLY BACKBUILD WWD TO MAINTAIN HEAVY
RAIN HAZARD OVER AR/OK BORDER REGION...AND CONTINUE SAGGING SWD
ACROSS NRN/CENTRAL AR.  NET EFFECT WILL BE EXPANDING AREA WHERE
EPISODIC/DISCONTINUOUS 2-3 INCH/HOUR RAIN RATES ARE POSSIBLE.
MERGING/TRAINING OF MULTICELLS WILL EXACERBATE HAZARD DUE TO
REPEATED PASSAGE OF CORES/CLUSTERS.

OUTFLOW BOUNDARY FROM EARLIER CONVECTION...AS OF 6Z...WAS ANALYZED
FROM NEAR CHA WWD NEAR TN/AL BORDER THEN TO NEAR MEM...BECOMING
DIFFUSE TO NEAR SRC.  SUBTLE CONVERGENCE ZONE AT AND ABOVE
SFC...ALONG AND JUST N OF SFC BOUNDARY -- SHOULD SERVE AS PRIMARY
FOCUS FOR FORWARD-MOTION OF COMPLEX INTO FAVORABLY MOIST AIR
MASS...BENEATH AROUND 25-30 KT 500 MB FLOW.  WEAK MCV...EVIDENT IN
REFLECTIVITY ANIMATIONS ALONG AR/MO BORDER BETWEEN FLP-UNO...ALSO
MAY PROVIDE SUBTLE ASCENT ALOFT IN SUPPORT OF CONVECTIVE POTENTIAL
OVER CENTRAL-NERN PORTIONS OF DISCUSSION AREA.

THROUGH AROUND 10Z...25-35 KT LLJ WITH RELATED MOISTURE
ADVECTION/TRANSPORT WILL SUPPLY WRN/SRN PORTION OF COMPLEX WITH
HIGH-PW AIR OF 2-2.5 INCHES...MATCHING VALUES EVIDENT IN MODIFIED
LZK RAOB AND RUC SOUNDINGS ALONG FRONT EDGE OF MCS AS WELL.
ADDITIONAL DEVELOPMENT IS POSSIBLE ATOP WRN LIMB OF OUTFLOW AIR
MASS...ACROSS WRN AR AND EXTREME E-CENTRAL/NERN OK...AS LLJ VEERS
OVERNIGHT WITH COMPONENT MORE NORMAL TO THAT PART OF MCS OUTFLOW
BOUNDARY.  HOWEVER...LLJ ALSO IS FCST TO WEAKEN WITH TIME AFTER
ABOUT 10Z...INDICATING GREATEST ORGANIZED HEAVY RAIN THREAT OVERALL
SHOULD BE WITHIN NEXT 3-4 HOURS.

..EDWARDS.. 07/13/2010

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

ATTN...WFO...MEG...LZK...TSA...

LAT...LON   36039492 36279405 36039301 36149175 35558910 34358959
            34899368 35259464 36039492



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