Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 020554
SWODY1
SPC AC 020553

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1253 AM CDT THU OCT 02 2014

VALID 021200Z - 031200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM A PORTION OF THE SRN AND
CNTRL PLAINS INTO THE LOWER-MIDDLE MS VALLEY REGIONS...

...SUMMARY...
WIDESPREAD THUNDERSTORM ACTIVITY WILL FORM ON THURSDAY ALONG A COLD
FRONT MOVING EASTWARD ACROSS THE SOUTHERN AND CENTRAL PLAINS INTO
THE MIDDLE MISSISSIPPI AND EVENTUALLY TENNESSEE VALLEY REGIONS. THE
STRONGER THUNDERSTORMS WILL LIKELY PRODUCE STRONG TO DAMAGING WIND
GUSTS AND LARGE HAIL. GREATEST LARGE HAIL THREAT WILL EXIST FROM
EASTERN OKLAHOMA INTO THE ARKLATEX AND OZARKS.

...SYNOPSIS...

A PROGRESSIVE UPPER TROUGH WILL ADVANCE THROUGH THE PLAINS AND MS
VALLEY REGION THURSDAY. A STRONG SHORTWAVE TROUGH EMBEDDED WITHIN
THE UPPER TROUGH BASE WILL CONTINUE THROUGH OK THURSDAY AFTERNOON
BEFORE REACHING THE LOWER-MID MS VALLEY DURING THE EVENING. A COLD
FRONT WILL ACCOMPANY THE SYNOPTIC TROUGH AND SHOULD EXTEND FROM THE
UPPER MS VALLEY SWWD THROUGH WRN OK AND WRN TX 12Z THURSDAY. A WEAK
CYCLONE IS FORECAST TO DEVELOP AND SHIFT NWD ALONG THIS BOUNDARY
THROUGH THE MID MS VALLEY INTO THE GREAT LAKES...WHILE THE FRONT
ADVANCES EAST...REACHING THE OH AND TN VALLEYS BY THE END OF THIS
PERIOD. A CONVECTIVELY REINFORCED WARM FRONT CURRENTLY FROM MO INTO
IL MAY LIFT SLIGHTLY NWD AHEAD OF THE COLD FRONT.

...SRN PLAINS INTO THE LOWER-MIDDLE MS VALLEY REGIONS...

AXIS OF RICH LOW-LEVEL MOISTURE WITH UPPER 60S-70F DEWPOINTS WILL
ADVECT NEWD THROUGH THE PRE-FRONTAL WARM SECTOR ALONG A /30-40 KT/
SWLY LLJ AND BENEATH MODEST 6.5-7C/KM MID-LEVEL LAPSE RATES. THE
WARM SECTOR SHOULD DESTABILIZE AS THE BOUNDARY LAYER WARMS DURING
THE DAY...BOOSTING MLCAPE TO 2000 J/KG FROM NERN TX AND ERN OK INTO
THE LOWER-MID MS VALLEY. ELEVATED STORMS WILL LIKELY BE ONGOING
ALONG WARM CONVEYOR BELT FROM OK INTO ERN KS AS WELL AS ALONG AND
NORTH OF THE BOUNDARY ACROSS CNTRL/NRN MO. HOWEVER...THE PRIMARY
ZONE OF THUNDERSTORM DEVELOPMENT IS EXPECTED AS DEEP ASCENT
ASSOCIATED WITH THE PROGRESSIVE SHORTWAVE TROUGH AND ACCOMPANYING
COLD FRONT INTERACTS WITH THE DESTABILIZING BOUNDARY LAYER FROM ERN
KS INTO CNTRL OK AND SWD INTO NCNTRL AND CNTRL TX. WIND PROFILES ARE
FORECAST TO BE MOSTLY UNIDIRECTIONAL DURING THE DAY...LIMITING THE
SIZE OF LOW-LEVEL HODOGRAPHS. HOWEVER...DEEP LAYER SHEAR WILL
INCREASE TO 40 KT WITH THE APPROACH OF THE SHORTWAVE TROUGH
SUPPORTING POTENTIAL FOR ORGANIZED STORMS. INITIAL STORMS COULD
EVOLVE INTO SUPERCELLS...BUT STORMS ARE EXPECTED TO GROW UPSCALE
INTO LINES ALONG THE FRONT. DAMAGING WIND AND LARGE HAIL WILL BE THE
MAIN THREATS...BUT A COUPLE TORNADOES CANNOT BE RULED OUT.

DURING THE EVENING AND OVERNIGHT A MOSTLY LINEAR MCS IS EXPECTED TO
CONTINUE THROUGH ERN TX INTO THE LOWER-MIDDLE MS VALLEY AND
EVENTUALLY THE TN VALLEY AS THE MCS INTERACTS WITH RICH LOW-LEVEL
MOISTURE AND AN INTENSIFYING LLJ. THE PRIMARY THREAT WITH THIS
ACTIVITY WILL BE DAMAGING WIND GUSTS...BUT A COUPLE OF TORNADOES
WILL ALSO REMAIN POSSIBLE.

..DIAL/MOSIER.. 10/02/2014



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