5/20/05 FCST: SD

[Douglas Mitchell]

Really optimistic about tomorrow's set-up. Both the NAM and GFS are in good agreement about a triple-point scenario for western SD. LI's nearing -8 and SFC cape around 3500 along with good directional and speed shear should set the stage for good supercells/tornadoes. Biggest concern is moisture return although I think any dews >55 or so will suffice given the higher elevation of W SD.

EDIT: My forecast "graphic" for tomorrow :lol: http://img.photobucket.com/albums/v144/mit...5/52005fcst.jpg

 

[Edward Ballou]

SPC/NWS seem to be favoring development more towards the north and east of your target area Doug. I'm seeing a possible blip(good forecasting term) at the southwest corner of SD but I wouldn't trust myself on that one. I think actually I will be in Pierre this weekend anyways so I will probably situate myself there and watch the advection across the gradient...

WOULD EXPECT THUNDERSTORMS TO DEVELOP OVER WESTERN NORTH DAKOTA AND NORTHWEST SD NEAR THE 925MB-850MB FRONT...THEN PROGRESS EAST AND SOUTHEAST INTO SOUTH DAKOTA. VERY STRONG INSTABILITY GRADIENT FROM WEST TO EAST AS WELL...WHICH AS MID LEVEL WINDS BECOME MORE WESTERLY...SHOULD AID IN ADVECTING THIS EASTWARD.

I'm still hoping for a better Saturday setup but it doesn't sound that way right now.