Use of Cloud Phase Distinction RGB to Anticipate Convective Initiation over Western Dakotas and Eastern Montana

 Some members of the 12z Thu Jun 10 HREF run were a bit slow in initiating convection or too far east in developing convection over the Northern Plains. The NSSL WRF-ARW was closest to reality with respect to exact timing and location. A special 18Z RAOB from Glasgow (GGW) MT and the Cloud Phase Distinction RGB proved to be very helpful in showing convection was going to develop earlier than anticipated by the HREF guidance. The 18Z RAOB from GGW (below) showed weak CINH values, while the Day Cloud Phase Distinction RGB (second graphic) showed an agitated cumulus field that was becoming quickly glaciated (single cell with yellow cloud top near the 93/61F sfc obs) indicating deep convective development was imminent.

Once deep convection initiated, single channel ‘Clean IR’ imagery and Day Convection RGB became more useful in determining updraft strength. These two products can be extremely useful in severe weather detection and warning decision making especially in absence of radar and/or lightning data or when used combined due to its faster temporal coverage (1-min in meso sector vs 5-min from radar).

The image above shows updrafts getting stronger in the 10.3 micron imagery (bottom left), and on the Daytime Convection RGB (bottom right) by evidence of yellow (red +green) pixels. Inflow feeder bands, a flanking line, towering cumulus above an invigorating RFD or flanking towers, and above anvil cirrus plume are also observed in the Day Cloud Convection and Cloud Phase Distinction RGBs (top panels) indicative of the storms likely being severe. In fact, the ProbSevere v3 and v2 output both indicated a very high probability of severe weather occurring with these storms with values over 90% (purple colors).

GOES Cloud Top Pressure vs Ch 13 IR

I'm not sure that I'm a big fan of the Cloud Top Pressure product for a few reasons:

1. It is too blocky/choppy, which makes it very difficult to use for a smaller, WFO-sized area. Certainly in the example below, the Ch 13 IR imagery has a much finer resolution, allowing a forecaster to more easily find/track convective cloud tops and their trends.

2. The default color scale makes it very difficult to determine where the higher/lower cloud top pressure values are. The blue to light purple transition above 300mb is too subtle, so convective cloud tops are not easy to find.

3. It doesn't seem to do a good job distinguishing cloud top pressures of thin cirrus, as we see below in areas east of the big convection.

Compare the GOES Cloud Top Pressure (top left) and GOES-16 Ch 13 IR (top right):

- Thomas Bell

Week 2 summary and comment round up

As week 2 comes to a close 11 May 2018, we review the comments from our final debrief below. Much of this echos the discovery and opinions from throughout the week.


GLM:

• Training remains an important question and consideration.  Would love to have subject-matter expert available locally for all forecasters (may become frustrated by the data and not use it w/o that person).  
• SOO or focal point can be that local subject-matter expert, however, this will demand evolving training exercises.  Move beyond VLAB, work with WDTD to create hands-on and locally-relevant training opportunities.
• Typical order of use this week:  Total Energy (primary), FED (secondary) and Flash Size (tertiary). 
• Limit the amount of data available on first release (only to the three products listed above???); eliminate point-based or centroid products.
• Integrate GLM data with ground-based lightning systems to help understand and alleviate parallax concerns, particularly when issuing a special weather statement or IDSS for lightning.
•  Want to work more cases and focus areas.  E.g., where radar coverage is poor (western US), fire weather, and aviation -- appears that areal extent and pre-Cloud-to-Ground information will be important.  Context is important and will drive various need/demand for individual GLM products.

ProbSevere (all hazards):

• Did not trust the probabilities in all environments this week.
• Did well with hail and if storms were a bit more steady state.
• Seemed to behave worse in western US and with wind threats.
• Liked using the probabilities as trend information for storm intensity, but not necessarily a particular number.
• Would like to see trend graphs not only of probs, but also internal items in algorithm.
• Preferred the individual hazard products (read-out too long on single ProbSevere)
• Some confusion regarding time scale of probability (minutes vs hour)
• ProbTor could be more difficult to understand reasoning for probs than other hazards; Use a lower threshold for ProbTor and adjust color tables accordingly.
• Would like to see "weak" "strong" indicators on more than just glaciation rate. 
• Difficult to pick out differences in storms between 70-100% probs; color table could use more delineation at higher end (all storms appeared pink).
• Could be useful to communicate impact w/public - would remove numbers and use Low - Mod - High for threats.

Convective Initiation (CI) and Severe-CI:

• Not terribly impressed by algorithm:  completely missed some objects, overdone in some areas, underdone in others.  Hard to understand why.
• Can provide situational awareness, does give some indication of development, but algorithm may need modifications to be more useful.
• Suggest either removing probs <30% or moving to transparent (to know algorithm is tracking these storms).  Large blue confetti-areas are distracting.
• Difficult to utilize in environments where noisy and chaotic. 
• Did not understand differences between algorithms (CI and SVR-CI):  why would CI be low and SVR-CI be high? 

All-Sky LAPS:

• Used in pre-convective environment, showed instability and moisture fields and gradients in those well.
• Could use in social media posts to explain the "WHY" behind the forecast.

NUCAPS:

• Data from JPSS integration was new (or relatively new) to most forecasters.
• Development of best-practices, easier menu-access (not buried in volume browser) and quick-guides would be helpful for increased use.
• Earlier access to data is highly important, but also need better visualization options.
• NSHARP options need to be more user-friendly, cumbersome to pull up multiple soundings in different CAVE displays to compare.  Would like to access shear parameters and get box&whisker plots.
• Difficult to evaluate trade-off of no-data available vs model integration into products.  Would like keep separate from LAPS options, but can be difficult to evaluate with gaps in data coverage in gridded products.

Supercell Merger VIA VIS/IR Toggle

Saw this VIS/IR Toggle with the supercells merging across Garden, Sheridan, and Cherry Counties in Nebraska. The coldest cores at the end of the animation are in the eastern portion of Sheridian where the main two supercells merged. Had Prob East on the image and did see where it was showing probabilities of cells along the forward flank could develop.

Supercell

Splitting of Supercells RGB Satellite Imagery

Here's some awesome satellite imagery from the splitting supercell from Garden County Nebraska off the Day Cloud Convection RGB.

More to come...

Supercell

No To Low CI and Storm Initiation

Noticed that a cell (circled on image) over northeastern Wyoming did not have any severe CI, low CI (17%) before it initiated. Not sure what may be happening with the algorithm. There was no cirrus canopy around the cell other than other convective initiation (south) and clear air (north).  Included the beginning image:

Here is the last image I took of the storm:

You can see that it has a strong updraft (via IR Satellite). I do not have severe CI displayed but it had no values in around that particular cell. With it moving towards a gradient in instability, could see it strengthen further soon.

More to come...

Supercell

SimpleWVRGB Compared with NUCAPS

Just playing with some RGBs...

Noticed that the Simple WV RGB was showing fairly continuous moisture returns at all levels across the LBF and GLD areas which is good verification that ample moisture is available over this area. Also, seeing the gravity waves to the SW stretching from San Diego CA to the Rockies within the more upper level moisture return (green colors).

Here is a NUCAPS sounding taken from eastern WY:

Here is a forecast sounding from the NAM12 from pretty much the same location

What I was trying to do was compare the nearly saturated environment shown on the Simple WV RGB with what I am seeing with NUCAPS and also NAM12 Sounding data around the same general vicinity of Wyoming.  What I think could be inferred is that the NUCAPS sounding is capturing the higher moisture better than the NAM12 all the way down to ~ 700 MB.  It may also be useful to compare multiple soundings around the eastern WY and NE area to see how it changes over time compared to the Simple WV RGB.


More to come...

Supercell

MKennedy Nucaps Start

NUCAPS notes: Computed LI values either did not appear or were computationally irrational-- unusable for 700-300 MB, would not appear as a single computation and therefore required a pressure level differential where ie. 850-700 mb was a required selection.

Possible anamoly or true most unstable CAPE MAX near Newton in NUCAPS Gridded at 1000-500 Most Unstable CAPE---comparing to East Mesoscal All-SKY LAP CAPE where only minor gradient seen.

Checking the Model Data for this possible CAPE an0moly showing HRRR upper left, RAP 13 Lower Left, with ARW upper right and lower right GFS. The right panel models indicate greater intensification near Newton and Downstream of Most Unstable Cape anomaly/gradient. See the images below at 00Z & 18/19Z for given model 4 panels.

Waiting on storm development to view event possibilities.


In the meantime, the RGB Day Land Cloud Convection is doing well with GLM highlighted in lower right panel as the developing anvil corresponds to growth and intensification.

Continuing to monitor the pre-convection environment over South Central Illinois near Newton, the RGB view of the Day Cloud Convection Procuct combine wtih the Derived GOES Lifted Index. Newton reads -3.2 no GLM data yet for this time frame of 21:20 Z with models suggesting development later toward 00 z in this location.

21:33 Z showing RGB Dust and ENI 5 minute data with one minute update Lightning, gradients around MCS and developing convection shown well

NUCAPS loading -10 to -30C temp lapse rates shows a white/gray upon transparency adjustment background-clear image more helpful to overlay on Water Vapor or other Sat. Imagery. When monitoring Newton again now looking back at 18Z Lapse Rates between -10 and -30C we can see a similar increase over Newton except in this instance,the gradient is not as pronounced on the Most Unstable Lapse Rates. Here we can view a ramping of the gradient in this region suggesting the data may not be compromised in the Most Unstable Gradient.


The GLM Looping over GOES 16 East Mesoscale 2 Clear IR Channel 10.33 um allows us to see storm propagation and matches the intensification along this warned line of storms in Central Illinois which verified with winds of 70 mph

 

Another interesting possible use of the Split Water Vapor with the radar overlay shows in Newton, selected here as the home location a gradient over this county that may help to intensify cells in this location or just downstream. 

 ++++split Water Vapor Loop gif would not load++++ 

RGB Composites and Channel Difference Labeling Suggestion

There are lots of RGB Composites and Channel Difference products being introduced with the GOES-R series.  They are very useful.  However, with more and more of these products being created, it's getting very difficult for operational meteorologists to memorize what each one means (including the color scales).

The quick guides that are being created are very helpful.  But it's not easy to view these quick guides in AWIPS.  It's also not always easy to view these guides online, especially if convection has already initiated.  As a result, some forecasters are limiting how many satellite products they view because they can't keep track of what each one stands for.

It would be very helpful to have the guides built into the products.  How?  The image below shows cloud phase distinction.  When the sampling option is turned on it gives more information about the image.  However, it displays Red/Green/Blue information.  This information is useful for developers, but useless for operational forecasters.

The quick guides created for each product display RGB interpretation.  If you view the quick guide for cloud phase distinction, the color orange (in the image above) is labeled in the guide as "Thin high-level clouds with ice particles (red-orange)."  This information should be built into the product.  In fact, it's already being done for radar.  Below is a Hydrometeor Classification image for radar.

Notice how all of the colors are labeled.  In the example above, the light blue is dry snow.  This same methodology can be used for the RGB composites and Channel Difference labeling.  It would make it much, much easier for operational forecasters to understand and remember each product.

-Kevin

Flagstaff Initital Conditions

Some convection has already begun across the Flagstaff WFO. The 4 panel WV loop has proved particularly useful already-namely the simple WV loop in showing a subtle wave moving west from New Mexico. This could help generate convection through the afternoon. Can also see it in the mid and upper level WV loop. Storms across the far western portion of the CWA appear strongest based on MRMS -20C reflectivity, GLM lightning and the sandwich GOES imagery.

Operational Helper

If possible, being able to create time series of GLM, MESH, GOES 16 data over a user defined area would be very helpful. While a storm tracking type area would be great, even a simple hand drawn polygon type application to identify areas to create time series would be very useful.

The following image, I think shows the need for this type of functionality. When storms become numerous, becomes difficult to figure out what storm is contributing what data to the lightning totals.

-JRM

LOT - Satellite Overview (with Derived Stability Products)

This group is starting the week in the LOT CWA, within the SPC Marginal/Slight risk area.

Taking a look at the derived stability parameters from GOES-16 highlights an unstable atmosphere to the west of the LOT CWA (CAPE values over 2000 J/kg and LI values around -7C).

I found adding the 0.64um Visible imagery below the derived data to be helpful in filling in the gaps where the cloud mask was in place.

Looking at a loop of the satellite data, there is a southward push of the lower stratus/cu out of DVN's cwa that may delay the start of convection some.

-GOB

GOES16 Not Labeling Products in AWIPS II

I'm fairly new with AWIPS II and using the GOES16 data is rather difficult figuring out which product I selected in the CAVE display.  My recommendation is to label the actual product in the bottom right instead of just listing the Channel and Microns.  It should label just like the drop down window for the GOES16 products.

--Dan S.

Clear Sky Mask

The default color curve for the Clear Sky Mask, Center CONUS, Derived porducts has black for both No Data and Clear. This needs to be changed.-ams

ABI Cirrus Ch 4

Here is an example of thin cirrus that is more visible over PA than on the CH2 Red VIS image. Top image is the Ch4 -ams

ABI and GLM helped again in taking a look

 

 Here's an example where the the sandwich product and lightning jump on the GLM grabbed our attention to look at a storm in our northern CWA. We were focused on the middle and lower part of our CWA so this was a great situation awareness tool today.

Sandwich for the win again

The one product I would want any day would be the IR/VIS sandwich. I also think this will be the most use to the Broadcasters as well. This has great value to the forecasters as well as the public in identifying how strong or severe storm can be.

SWD_IR is agreat for day and night operations.

One of my go to products in the 1st two days has been the sandwich products of the IR/VIS and The SWD_IR. Really see many advantages to having this looping on me desktop during my entire shift.