Severe Weather Discussion for August 28 – September 3, 2006.
– Below normal temperatures all week. Yes, you read that correct, below normal temperatures for Oklahoma.
– Chance of thunderstorms on Saturday.
– Severe Thunderstorms in Oklahoma: 25%
– Storm Chase: 5%
– Winter Precip: < 5%
Southern stream shortwave trof initialized much stronger on the 00z GFS than had been progged by recent model runs. The NAM-WRF had a better solution with this system and it moved quicker than the GFS had indicated. Much of this is why Ernesto is turning northward so quickly.
Another cold front is expected later today as the previously mentioned shortwave trof continues east. Combination of wet ground and cold air advection should keep temperatures below normal this Mon-Wed. OKC is now 4.75 inche below normal on the yearly rainfall total. Current normal high is 90F.
By Thursday a stronger northern stream shortwave trof approaches the region. GFS takes this system across the northern U.S. with little mid-level energy in this area. I’m not going to bite on that solution given GFS’s tendency to weaken systems too much. NAM-WRF is a little stronger at 84 hours and this could impact the forecast for next weekend. With southwest flow aloft and a strengthening lee trof, temperatures should warm to or slightly above normal across the state. Texas may warm a little more as the ground remains quite dry there.
Saturday should see the upper system move across the region. If the GFS is correct, then a squall line is possible along the cold front late Saturday with much cooler temperatures behind it. If the upper system is indeed a little stronger and slower, then more concentrated severe thunderstorms are possible. I’m going with a low-end event (basically a slight risk) for the weekend. NHC has a risk area up in the Day 4-8 period and this looks okay given model progs. Either way, temperatures on Sunday will be noticeably cooler.
Ernesto has done us a favor by going into Florida and being a weak system. Hopefully the rain will continue across this part of the country. Tropical season is seasonably active with two systems this past week. Wouldn’t surprise me to see at least one more this week, Ernesto aside.
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