Week 4 Day 4 Operations

Forecasters today will wrap up the week operating in the Bismark, ND and Rapid City, SD CWAs.

-Michael

Day 3 Wrap Up and Feedback

Day 3 saw forecasters operate in the Melbourne, Fl CWA all day monitoring some weak sea breeze convection, and in the Sioux Falls, SD CWA monitoring an initial MCS and later some strong storms forming off of the remnant outflow boundary. Discussion feedback is posted below:

GLM

Seeing the anvil lightning was really cool to see how far the extent of lightning can be from the parent storm

Saw GLM flashes and NLDN CG flashes ~90 miles from storm core

In Florida it was easier analyzing the storms using the flashes to keep the storms separate from each other

Looked at different grid resolutions and the 9 - 10 km resolution seemed to work best

5 km resolution was to “pinpointy”

Events made the most sense to use over groups

Liked the Stano test color curves as the easiest to look at quickly and pick up the trends and hot spots

Parallax issue would probably be a big issue in the field

First impression is a big deal, and the parallax issues should be fixed before fielded in the offices

Much rather have the GLM combined and color curves here to use in the field, it’s much more intuitive

NUCAPS

No gridded data in Florida

Sounding were a lot better representation of the atmosphere yesterday than previous days

Showed a bit of a weaker cap in the gridded data than the RAP and the cap did end up breaking shortly after

Very useful for initiation yesterday

Having more passes the better, especially in the early afternoon time frame

Soundings are consistently doing pretty well above the boundary layer

Like having the option for both the operational and the experimental soundings depending on the boundary layer environment

ABI

“I like it”

Monitoring for initiation was nice for monitoring for glaciation

Cumulus field turning to stratocumulus showed a capped environment

Day cloud phase RGB shows glaciation really well

Used the 3.9 yesterday to pick up some thermal difference

Obviously not all bands are going to be used by themselves

None of the other bands really jumped out too much with the pulse convection

Low-levels of derived winds have very little information

ProbSevere

A couple of large ProbHails in Florida that seemed a little unreasonable for the tropical environment it was in

ProbTor highlighted the part of the bow that was most intense and capable of tornado production

It highlighted the part of the line that was different

Some of the tracking, especially on lines needs some work to be useful in line events

Overall it’s a great tool that seems ready to be used in operations especially as a SA tool

It forces you to really interrogate the storms of interest to see what is going on

Helpful for people with lower radar experience to fall back on for interrogation

-Michael

Another Anvil Lightning Event - Near Akron Iowa

GLM picked up another case of anvil lightning at 2341 Z near Akron Iowa.  CG occurred at same time as GLM events were noted, so no real lead time to this strike was observed. Image below of accumulated 5 minute GLM event density and flash data updated every minute along with the NLDN CG strikes.

For reference this image indicates how far the main area of storms was from lightning strike (white dot). There were some 30 dbz echoes near Vermilion SD but they never grew much stronger than that during this period. This was around 90 miles from main storm area.

-JRM

Anvil Lightning-Near Yankton

Interesting to see a cloud to ground lightning strike occur well away from main updraft cores in area with little if any meaningful reflectivity. Following loop is focused on the Yankton area, well removed from the main cells of thunderstorms. Image is a combination of GLM  5 minute accumulated event density and MRMS 1 km composite reflectivity.

A couple of things stood out to me. First you see the area of GLM areas of GLM events extending over the area followed by a few flashes, followed by a NLDN positive strike southwest of Yankton.  The following image shows how far away that was from main core of storm. White dot represents location of positive cloud to ground strike.

-tvguy/jrm

JAX Pulse Storm

In the JAX CWA, a storm seemed to intensify along a shear zone which was detected well in the upper level water vapor imagery. The intensification was noted mostly via rapid cooling of the cloud top temperatures seen in the IR imagery as well as the 1 min update of the GLM flash density at 8km. I forgot to load the PROBSevere before saving this image, but PROBhail did increase to 30% for a scan or two (which was very good for us today)

Advancing Outflow Boundary - FSD area

Following loop indicates what appears to outflow from earlier MCS advancing to the south across southern portion of the CWA. Interesting to see it interact with area of cumulus. Can see cu field increase as feature passes. Also gives some indication of overall stability as clouds seem to form into more of a stratocumulus deck with no deep vertical development observed. Increased resolution made it much easier to see reaction to this forcing.

JRM

ProbSevere from west of MLB

ProbSevere jumped to 69% for hail with a storm west of the MLB CWA. 55 dBz was noted at the -20C level and 50 dBz to 33 kft. A  hail threat this high still seems a little ambitious for central Florida in July given the marginal mid level lapse rates and tropical environment. 

-64BoggsLites

Day Cloud Phase loop from MLB this afternoon.

An example of a line of cumulus along an outflow boundary growing deeper and eventually glaciating to the west of MLB late this afternoon.

Along with a loop of the GLM interpolated flash product. Lightning seemed to remain focused with the strongest updraft in this case.

-64BoggsLites

FL storm development along boundary

Not much going on over the last few hours across the CWA. However, the IR overlaid atop vis imagery shows a storm strengthening along an outflow boundary just to the west of our CWA border. Lightning increase was seen in this storm as well. This "sandwich" image proved to be very useful in identifying the outflow boundary itself while also showing how a thunderstorm developed along it with cooling cloud tops

Storm IR comparison

Intense storm diving south out of FSD area into Boyd and Holt counties. Coldest temperatures got around -79.5 C for a time and area of subsidence/warming noted around periphery of overshooting top. 

Interesting to compare the GOES-16 IR imagery to GOES-13 data. (Images below) Aside from the differences in spatial resolution, the latency in GOES-13 data results in what appears to be a shift in position of the overshooting top.  This position closely resembled where feature was located about 7 minutes prior. So not only does GOES 16 provide higher resolution and more frequent images, its data can also be used to more accurately position features (although paralax remains a potential positional error)

-JRM