ENI Cell Polygons: Complete Overlap Should Not Occur

The loop below depicts two ENI Cell Polygons completely overlapping  – which seems less than desirable. This overlap is depicted for a tornadic storm below and clearly the fetal polygon can be seen within the womb of the mother polygon (loop image underlay is the 0-2km Azimuthal Shear).

Also seen is the lightning ramp up in the pre-tornadic phase as the cell strengthened.

RockyILMTor_PolyOverlap

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ENI data should prove very useful over marine zones

In areas that are poorly sampled by radar data…such as mountainous and farther offshore marine locales..the ENI data should prove to be very valuable. The ENI data could be the confidence factor in issuing or not issuing a special marine warning on a storm that looks to be marginally strong due to poor radar sampling.

Pickles

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Utility of 17z NUCAPS sounding in MHX

The NUCAPS sounding has shown to be a realistic supplemental piece of environmental  data the last several days.

In comparison with the 12z sounding (fig 2)…the 17z NUCAPS (fig1) sounding did subtlely pick up on a weak inversion around 700 mb and 850 mb that was evident in the 12z sounding.  The NUCAPS sounding was more moist in the 400-500 mb level than the 12z sounding…which may have been due to the cirrus advecting in ahead of approaching convection. Differences between the 12z and NUCAPS soundings can give a rough and general idea of change in environment.

In comparison…with 17z SPC meso-analysis (fig3)…MU CAPE value were comparable.

So overall…I have been pleased with the utility of this sounding for re-assessing the environment each afternoon. It may be especially useful to sample a few NUCAPS points in an area of concern to get a consensus picture of the environment.

Fig 1 – 17z NUCAPS

17z NUCAPs

Fig 2 -12z MHX

 

12z MHX sounding

Fig 317z SPC meso

Pickles

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ENI cell tracking/rate better utility than Lightning Jump in detecting tvs’s along QLCS across MHX

ENI cell/rate tracking (fig 1) was a better tool to identify and track stronger updrafts (fig 2)…within a QLCS moving to the NC coast. The lighting jump algorithm was difficult to follow one the event transitioned to a QLCS setup…because the algorithm grouped together severe cells and washed out the jump/severe signal (fig3).

Transient and weak tornadic spin-ups are noted on occasion along the NE coast with these QLCS’s in areas of interaction with discrete cells, to the north of rear inflow jets and kinks in the line.  Although both tools would likely not give much lead time on these transient spin-ups…the ENI should prove a more useful complement to radar data in these areas than the lightning jump in detecting the highest severe winds threat along the line and best potential for tornadogenesis. 

Fig 1ENI 2022z MHX

Fig 20.5 SRM MHX 2025

Fig3Lightning jump 2023z

Pickles

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LJDA Clustering Too Large To Take Action On

To Whom It May Concern:

The LJDA, in a general sense, clusters too large an area for proximity storms, such that action is difficult to take. In a general sense, the sigma value of the larger cluster still draws SA. The cell ID algorithm in the ENI data generally has performed well over the past two days and the polygons would offer a nice area to calculate the LJ.

Display Suggest: By merging the ENI and LJDA info, could the ENI Cell Flash Rate text info contain a “.sigma” value following the 1 min strike total. For example, an ENI cell polygon contains 45 flashes in the last minute with a 3 sigma. The text would display “45.3”.

Rocky

LJDA_2058Z

LJDA_2058Z_raw

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Evaluation of products during ILM tornadic storm

Tornadic storm in eastern Columbus / western Brunswick Co NC around 2010Z to 2020Z.0521 ILM 4 panel B

0521 ILM 4 panel AProb Severe
2004Z – model merged cells, value at 79%
2012Z – prob severe peaked at 95% as tornado was likely occurring
From 20Z to 21Z the storm moved from a 1600 ENV MUCAPE environment to 2100 CAPE environment.  Over that same time ENV EBSHEAR dropped slightly from 28 kts to 26 kts.  MESH peaked in tornadic cell at 2″ at 2018Z.
In southern cell, MESH passed 1″ at 2038, prompting severe t-storm warning.  Peaked at 1.26″ at 2042Z.

Lightning:
Pictured first is trend on cell responsible for tornado warning.  Significant weakening trend also seen on radar presentation as southern storm took over.

Lightning jump in southern storm (second picture) happened between 2030 and 2035, several minutes before severe hail indicated (above).
0521 ILM trend A 0521 ILM trend B

Overshooting top: detected over most of the 20Z to 21Z time frame
0521 ILM top

PHI tornado product
0521 ILM  phi tor

-Holaday

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