4/6/10 FCST: MD

[Jim wyman]

All,
I am seeing some very interesting indices occuring around the 0100 UTC time frame for KNHK and surrounding area. While some of these numbers are hours out and may not seem huge for the plains, they are someswhat unusual for MD... I wanted some inputs from some of the experts here as to what YOU see for severe weather this late evening....


Thanks!

Jim

 

[Geoff Manikin]

not sure what indices you're talking about, but there will definitely be modest cape and moderate shear across southern MD this evening - nothing synoptically looks particularly wild, but svr would certainly be possible if a storm formed.

The problem, though, is that we're hopelessly capped:
http://www.emc.ncep.noaa.gov/mmb/namsvrfcst/images/Tue/12z/mucins12.gif
You would need extremely strong forcing to get a storm up today, and there is no front or vort max anywhere in the region to provide that. I don't think that a bay breeze is gonna get a parcel through that cap. No model suggests convective initiation in the Delmarva area today.

 

[Jim wyman]

Looking at the 12-hour RUC runs and BUFKIT data..... showing EHI, SRH, moderate CAPE.....

 

[Geoff Manikin]

I see what's going on. The RUC is trying to develop 70+ dew points into southern MD this evening. NHK at 18z has an observed 55 dew point, so that the model seems way too high. With those dew points, the RUC has 2000+ cape into southern MD and close to 3000 in eastern VA, so I can see how that would make for some really nice EHI values, but I suspect that the NAM's cape of 500 to 1000 is more reasonable.

And I should note that even with RUC generating CAPE that will likely be way too high, it is still unable to generate any precip in the Delmarva region.