For the week of 14-18 May, our distinguished NWS guests will be Brian Carcione (WFO Huntsville, AL), Todd Dankers (WFO Boulder/Denver, CO), Stephen Kearney (CWSU Memphis, TN), and Julia Ruthford (WFO Charleston, WV).  Other visiting participants this week will include Dave Carlsen (Environment Canada), Bob Aune (UW-CIMSS), Jordan Gerth (UW-CIMSS), Lori Schultz (UAH), and Chad Gravelle (GOES-R NWSTC liaison).

The pattern at upper-levels features a large ridge in the western US and a weak but large trough in the eastern third of the CONUS.  Two areas of potential severe convection exists in the CONUS, along the Rio Grande valley in TX and the southeast Atlantic coastal states.

The southwest TX threat area comes in response to one weak short-wave trough embedded in northwesterly flow east of the ridge settling southeastward from NM yesterday.  This trough is phasing with a low-level front along the Rio Grande river from south of Marfa to near Del Rio and eastward.  However the moisture has been scoured a bit from an overnight MCS that passed southeast from Del Rio.  We expect diurnal heating and moisture return from the east to destabilize the atmosphere and allow new diurnal convection to form from the Big Bend region, east.  There are factors limiting potential severity of convection including uncertain amounts of destabilization and weak low-level shear.  Nevertheless, supercells  producing large hail and some damaging winds are possible in this threat area.

The second area in the southeastern Atlantic coastal states is already active with convection.  A QLCS is progressing across the central Carolinas while more isolated convective forms are developing all the way down into FL.  The deep layer shear is a modest 25-30 kts/6km in the Carolinas, and weaker further to the south.  The QLCS should continue moving eastward with a small threat of damaging winds while isolated downbursts and marginally severe hail is possible down into FL.

A forecast team is already monitoring Wilmington, NC’s area (Brian Carcioni and Todd Dankers) and the second team is monitoring San Antonio’s area (Stephen Kearney and Julia Ruthford).

Jim LaDue, EWP2012 Week#2 Weekly Coordinator