jeudi 2 octobre 2014

Oct 2, 2014 0600 UTC Day 1 Convective Outlook

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.

Aucun commentaire:

Enregistrer un commentaire