Saturday, May 29, 2010

Back out on the Plains: Forecast 5/29/2010

I'm back out on the Plains for about a week and half of what looks like modestly impressive setups for several discrete cell systems this year. Beats the hell out of last year already (and that's an understatement).

Currently I'm in the Nebraska Panhandle in a small town called Scottsbluff. My forecast is for areas just south of here. For a technical smorgasbord:

I think my forecast may be getting RUC'd-up at the moment...

Pluses this am:
Morning sfc data for the NE PH area and N KS are showing Tds in the 50-60+ range with sfc winds out of the south at 10-20kt. RUC is forecasting EHI over the Ogallala, NE, area to be in excess of 6 (with 0-3km SRH >400) by 00z suggesting availaible helicity in an area of forecast lapse rates between 6-8deg. SBCAPE will be in excess of 2000 along the I-80 corridor. The LSI shows this area to be under a "perfect" capping inversion (LSIs 1-3) that should suppress convection until either convective temp is reached (unlikely) or convergence/upslope forces convection (possible). The 4km WRF is suggesting that isolated cells will develop by around 22z over Sydney-Ogallala line with a possibly more discrete cell just south into CO.

Negatives this am:
The 00z from yesterday show that the GFS solution for a more progressive trough over the NE PH is unlikely, and that the NAM solution was more correct. This am's RUC appears to split the difference and place the trough just off the WY front range by 21z. Looking at this morning's water vapor image, it seems that the more westerly solution is likely the correct one. If the trough can move a bit more east than that, then the NE PH will be under the influence of the right rear entrance region of the jet and could have further lift from that mechanism as well. This morning's 00z KBLF sounding showed very high LCLs (>1500 ft), and this is without daytime heating that will likely augment the T/Td spreads. Last, an sfc backing is going to have to be due to a mesoscale low event since forecast sfc winds are just a mess on the RUC and NAM for later today.

Preliminary Changes to Forecast:
At this point I'm in Scottsbluff, NE, but will likely begin to meander south to Kimball, NE, where I'll try to further target refine.

As always, you can chase along with me by following my car icon below :)!




No comments: