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

Fig 2 -12z MHX

Fig 3

Pickles

The GOES-R LAP Parcel LI showed the destabilization trend through the eastern Carolinas ahead of convective initiation. The LI gradients compared well to the HRRR model – and both illustrated a sharp northern instability gradient limiting convection into Virginia. Good confidence builder and visualization tool.

Rocky

UAH CI probabilities have increased up to 70% along the cold front moving through extreme northeast South Carolina. UAH CI probs have been slowly increasing and the highest signals do correlate to where weak echos are now showing up on KLTX.

George

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 1

Fig 2

Fig3

Pickles

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

Tornadic storm in eastern Columbus / western Brunswick Co NC around 2010Z to 2020Z.

Prob 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).

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

PHI tornado product

-Holaday

We’re keeping an eye out along the southwest portion of the cold front across ILM CWA for convective development. So far, SRSOR shows little cu towering and the UAH Convective Initiation is keeping probabilities around 50% or less.

George

At 1915z…a small supercell over Quitsna NC (fig 1)exhibited severe characteristics of 60-65 dbz above the -20c level and a low/mid level meso. Interestingly the small size of the reflectivity core and likely updraft volume limited lightning with the storm.  The 70 percent eni lightning detection efficiency in the area could also have been a factor.  This is seen in the -999 sigma lightning jump (fig 2) and only 9 cloud flashes in eni and no cg (fig 3).

It was not until 1938 that the lightning jump algorithm showed a 2 sigma jump (fig 4)…and then 1940 a 3 sigma jump that the algorithm itself would have alerted to a severe cell (fig 5)

Prob severe at 1915z was only 40 percent (fig 6)…because heavy cirrus from storms to the west negated the satellite growth algorithm.  The algorithm was consequently all weigthed towad mexh. It was not until 1925z that the mesh got big enough to have the prob severe go over 60 percent (f ig 7).

Due to the slow lightning growth…DTA were also slow in in detecting this storm. Not until 1930 for a significant DTA (Fig 8), and not until 1950z for a dangerous DTA (fig 9).

Fig 1

Fig 2

Fig 3

Fig4

Fig 5

Fig 6

Fig 7

Fig 8

Fig 9

There have been several storms in South Florida with ProbSevere greater than 80% and ENI Dangerous Tstm Alerts. This corresponded with lightning jumps as seen in the bottom image, but were quickly followed by equally rapid drops in lightning. ProbSevere mouse-over info briefly indicated strong Norm Vert Growth Rates and Glaciation Rates. The MESH values are topping out around or just above 1 inch. If there is any severe weather at the surface it is likely very short-lived – maybe 10 minutes or so. Nearly all of these cells are in unpopulated  areas.  In this environment we are not seeing sustained updrafts.The ProbSevere and ENI Alerts still help you focus in on the strongest storms…but in the context of everything else are not indicators (so far today) that a warning should be issued.

-snowstrm

Radar imagery showing a storm intensifying across central Miami-Dade county (highlighted by the white arrows) due to a collision from outflow from convection to the northwest. As this storm intensified, the prob severe increased from 7% to 79% in two volume scans…as seen in the below images.