June 17th Severe Weather Outlook
It seems like the continuing story across the central USA has been the hot weather! That will continue to once again be the case today as well as temperatures are going to be on the hot side again. Temperatures will be in the 80-100 range..
http://www.twisterdata.com/data/models/nam/221/maps/2012/06/17/00/NAM_221_2012061700_F18_TMPF_2_M_ABOVE_GROUND.png
To go along with the hot weather will be the stickiness and the humidity in the air with dew points in the 60-70 degree range..
http://www.twisterdata.com/data/models/nam/221/maps/2012/06/17/00/NAM_221_2012061700_F18_DPTF_2_M_ABOVE_GROUND.png
CAPE or INSTABILITY will be 500-3500 across the severe zone..
http://www.twisterdata.com/data/models/nam/221/maps/2012/06/17/00/NAM_221_2012061700_F24_CAPE_SURFACE.png
LIFT INDEX
The lift across the severe zone is from 0 to about -10 depending on where you reside..
http://www.twisterdata.com/data/models/nam/221/maps/2012/06/17/00/NAM_221_2012061700_F24_PLI_30_0_MB_ABOVE_GROUND.png
SHEAR
Shear will be from 30-60 knots across the region..
http://www.twisterdata.com/data/models/nam/221/maps/2012/06/17/00/NAM_221_2012061700_F24_SHRM_500_MB.png
HELICITY as high as 450
http://www.twisterdata.com/data/models/nam/221/maps/2012/06/17/00/NAM_221_2012061700_F24_HLCY_3000_M_ABOVE_GROUND_0_M_ABOVE_GROUND.png
Problem is where the helicity is high across the northern regions there is no precipitation..in those same regions..
http://raleighwx.americanwx.com/models/nam/00znam850mbTSLPp06024.gif
This leaves us with the ENERGY HELICITY INDEX..
24 hrs. out . 8 PM
http://www.twisterdata.com/data/models/nam/221/maps/2012/06/17/00/NAM_221_2012061700_F24_EHI_3000_M.png
27 hrs. out 11 PM
http://www.twisterdata.com/data/models/nam/221/maps/2012/06/17/00/NAM_221_2012061700_F27_EHI_3000_M.png
30 hrs. out 2 AM
http://www.twisterdata.com/data/models/nam/221/maps/2012/06/17/00/NAM_221_2012061700_F30_EHI_3000_M.png
So the EHI in place would be indicative of tornado potential in Minnesota to IOWA to the East side of South Dakota..to the east side of Nebraska and the north side of Kansas.
The problem becomes in how much moisture return do we actually get? We have parameters that are supportive but we are also dealing with ridging/capping in place ..
So what are we dealing with here? We have a low pressure area across the southern tier of Canada with a stationary front going thru Upper Michigan dividing the state in half and then proceeding to the South South west to another area of low pressure over Western KS.
http://www.hpc.ncep.noaa.gov/basicwx/91fwbgus.gif
This front will continue to push towards the east by early morning hours Sunday (8am)
http://www.hpc.ncep.noaa.gov/basicwx/92fwbgus.gif
And by evening time you can see that this front has pushed well to the east towards Ohio.
EHI as we stated would be supportive of tornado's but with CAPPING in place I think we are going to scale back on what could normally be a higher tornado percentage and just go with a 2 % chance. Most else where will be dealing with scattered severe storms with winds and hails and heavy rains as the primary threats...
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