EWP Daily summary: 2012 May 16

We focused operations in both the Burlington, VT and Albany, NY CWAs ahead of a strong upper-level storm and cold front.  Stephen and Todd started issuing warnings with the help of MRMS MEHS product in northern Lake Champlain at 1820z.  Shortly afterwards (1915 Z) Brian and Julia issued a SVR warning in Herkimer county, NY following indications of a three-body scatter spike and dual-pol hail signatures.  Neither the MRMS or 3DVAR showed strong storm indications.  But Brian noticed storm top divergence > 9.5 s^-1 in the storm top.  Both storms produced hail ~1″ in diameter but no wind reports.  Ten minutes later, the UW CTC showed large negative values in eastern Hamilton County, NY as the storm continued east.

Both teams kept issuing severe tstm warnings as the storms continued east and new ones developed west of Albany.  The BTV team noticed that CI was useful for areas where outflow initiated new storms far enough away from old thunderstorm anvils.  They also liked using the 3DVAR vertical velocity.  One severe storm with a MEHS of 2″ showed updraft strength of 14 m/s at 2018 UTC over Essex County (BTV’s area).  They also noticed max updraft preceding max reflectivity by up to 20 minutes.  Meanwhile Todd and Julia focused on peak storm top divergence in 3DVAR.  Todd believed that product actually helped with lead time before reports arrived. The Albany team thought the MRMS azimuthal shear, and the 3DVAR updraft vorticity was useful in identifying intensifying storms.  They also found the nearcast theta-e differences successfully flagged the ridge of instability going up the Hudson Valley.

As the action wound down in BTV, Todd and Stephen worked with the CI team on flagging new convective initiation along the tail end of the front in northeast Arkansas.

Some limitations came out too.  Julia found that the 3DVAR barely perturbed the flow around a bow echo east of Saratoga, NY.  So she used traditional radar interpretation to assess the storm.  The Albany team would also have liked a quick cross-section ability.  Julia issued a flash flood warning but didn’t use the new products in the decision-making namely because she had no familiarity with how they may be used for that kind of product.

The Albany team also had issues with CAVE and Warngen with occasional crashes and slowdowns.

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