NWIASpotter's Severe Weather Forcast for 10/22
Posted: Thu Oct 21, 2004 9:15 am
by NWIASpotter
I have looked at both Eta and Gfs from last nights run. They are no longer in great agreement to the location of where the storms will fire. Eta puts most of the energy in MN/WI. While GFS puts it in IA/MO. Both are in agreement that the area of greatest intensity will be just to the southeast of the Low. Most forecasters are putting this low around the FSD area tomorrow afternoon, evening. There will be energy available, as dewpoints are expected to be in to the 60's. Temps should be up to near 70 degrees. There will be enough shear in the atmosphere for tornadoes to be a definate possiblity. An area of moderate risk for severe weather will most likely be included tomorrow if these conditions hold up. I believe it will be from an area of Ft. Dodge, IA...southward through Des Moines, and down to near Kansas City. It should stretch about 75 statute miles east/west from the DMX area. A slight risk should include the rest of IA/MO/southern MN/KS/and other areas in the plains.
Posted: Fri Oct 22, 2004 7:34 am
by NWIASpotter
The best area for severe thunderstorms has shifted to the north and to the west. Directly over my area, as well as Jeff's. Last nights ETA and GFS both are in good timing agreement I believe. ETA has backed down a little on the intensity of these storms. But, there still remains the potention for hail up to 1" in diameter and winds to 60 kts. The RUC2 only goes out to 12 hours, and the latest one available currently is the 9z. SO it does reach the prime time for these severe storms yet. The current ETA model from 00z is not to impressive with the possibilities over this area. Although all of the conditions are favored for severe weather, the model doesn't pick up on these and leaves a lot of the area clean. The GFS I believe does a lot better on picking these signs up. It does start to form somewhat of a band of heavier storms along western Iowa by 21z. But it then also loses this band of heavier rain. All of the elements are there for severe weather this afternoon, shear is high, up to 2000 J/kg of CAPE are forecasted, the SWEAT index is high. It will be something to watch, I will try to keep this updated when the newer models come out.