OUN: CI products

Forecaster comments from EWP blog...

UAH Convective Initiation images showed a brief value of 65 in northeast Comanche County but the UW_CTC product never showed a cloud top cooling value. This seems to be due to the proximity of the cluster of cells to the west. The cell in northeast Comanche County was very slow to develop, but did become very strong and actually produced a 62 mph wind gust. Additionally, the MESH showed hail sizes of over one inch.

UAH signal at 1915z in NE Comanche Co.

Cell first noted at 1925z

One inch hail detected 45 minutes after initial reflectivity blob on radar, and 55 minutes after UAH signal.

Evaluation of UAHCI early on in MLB

Forecaster comments from EWP blog...

Looking across FL, much of the area was obscured by thick high clouds, making the CI products impossible to calculate/use. However, at 1710Z, the UAHCI algorithm did indicate possible CI just off the eastern FL coast, with a relatively low strength of signal of 30-40. Of note, the UWCTC algorithm did not hit on this cloud mass at all. As the follow image at 17:45Z shows, the band of clouds with a low SOS did not develop and actually diminished. This is within the expected outcome given the low SOS.

MLB: Checking out the RGB Airmass GOES Sounder product

Forecaster comments from EWP blog...

Thunderstorms over our region are fairly tame at the moment, so I began checking out some other interesting products.  Here is a shot of the RGB Airmass product produced by the GOES sounder.  GOES-R will have a similar image.  This basically takes information from four different wavelengths and combines them into one image.  Reddish colors here are high PV air associated with the jet…notice the band across the western Great Lakes.  Blue indicates a cooler airmass with associated midlevel clouds…notable across the northeast US.  Greenish colors are thicker low-level clouds with a more moist airmass…not surprisingly, the southeast US shows this.  Yellowish colors, such as over the Pacific Northwest, are low-level clouds in a cooler airmass.  White areas are deep cloud decks, often over convection, like Florida and the eastern Gulf.  Looping this product can show airmass movement and jet position/structure.  This can be useful as a check against NWP models.  I’ve posted both the RGB product (top) and the normal IR image at the same time (bottom) for comparison.

JAX:Cloud top cooling and marine supercells

Forecaster comments from EWP blog...

CTC and CI products have shown promise today despite shield of cirrus/anvil blowoff. The above image illustrates large CTC at 1910z.  Within 15 minutes of this image, a line of small discrete supercells developed just offshore.

PGLM in AWIPS II

Today we have a couple forecasters operating over the Melbourne CWA watching the PGLM product.  This has been our first chance to grab a good screenshot of what the PGLM looks like in AWIPS II this year since there has not been a lot of activity over the LMAs during this Spring Experiment.  In the image above you can see a 4-panel display of the PGLM products that we provide within AWIPS II.  The top left is the instantaneous 1-minute flash rates derived from the LMA.  In the top right, we have a 60-minute maximum flash rate product, which takes all of the instantaneous flash rates over the past 60 minutes and only plots the maximum.  The bottom left is the 60-minute accumulated flash rate product, which takes the instantaneous flash rates over the past 60 minutes and sums them up.  The later two products are an attempt to provide forecasters with a crude 2-D track of the flash rates so that they can have some information on the history of the lightning activity.  A major change from previous years' display of the PGLM is the color table.  Forecasters did not like the old table which was did a poor job in differentiating small changes in flash rate.

EWP daily debrief 6/5

Yesterday's event was mainly spent familiarizing the forecasters with AWIPS II, how to load the products and setting up procedures, so active operations were somewhat limited.  Below are some of the feedback we gathered during today's debrief.

SATCAST / UW Cloud-top Cooling
- "We looked at it (CI and CTC) after the fact and it looked liked it picked up on the initiation really well."
- "There were only two cells that had advanced warning on the CTC, but the rest fell apart right after the signal."
- "Given yesterday's setup, it was very marginal, pulse-type storms... I was pretty impressed by the way the CI product handled it with cells going up all over... the CTC product really helped key in on what cell was most significant."

PGLM
- For some reason the West TX LMA data was not meshing well with the way the domain was set up in AWIPS II, so flash amounts were low and offset... we had to use an external WDSSII display for the Lubbock forecasters to look at.
- "For the limited amount we got to look at, I liked the PGLM a lot... it was very very handy."

Nearcast
- Cloud cover mostly obscured the areas of interest yesterday (Lubbock/Amarillo) due to ongoing convection.
- Forecasters really liked the CAPE product and look forward to seeing it throughout the week.
- "There were a few holes around where observations were made and it matched up with some of the meso data."

Overall / Training
- "It would be helpful to show the boundaries for the products that don't cover the entire area."

LUB: Day 1 – Getting Familiar with Products

Forecaster comments from EWP blog...

Shortly after entering the lab, thunderstorms quickly fired up over our area of responsibility. While getting familiar with the new forecasting and diagnostic tools, we were quickly thrown into a “warning operations” situation.

The OUNWRF did a fairly good job handling the timing and location of convective initiation this afternoon (Figure 1). Along with using the OUNWRF, we also tested the UW-CIMSS Cloud Top Cooling tool. The UW-CTC tool did a great job picking up the areas of developing convection across the CWA This afternoon. UW-CTC algorithm seemed to have only two”false alarms”, one of which being the result of some high clouds. It was pretty easy to identify the “false alarm” as the CTC rates were extremely low (on the order of -5C/15min), compared to CTC rates around -20C/15min (observed with most of the developing activity).

The second “false alarm” occurred when the CTC algorithm tagged a developing storm with CTC rates from -15 to -20C/15min (figure 3). After warning on this storm, we waited for LSRs and never saw a report to verify the warning.

Despite a couple of false alarms, we were very pleased with the performance of the OUNWRF with respect to the storms becoming outflow dominate and producing more wind damage than hail. We received wind gust reports greater than 60mph in the LBB area, as well as numerous downed trees. Figure 4 below illustrates the surface max hourly wind speed. Typically winds greater than 20m/s should raise heightened awareness and the potential for damaging winds.

Had we a little more time to become familiar with the products and get “spun up” with our procedures and whatnot…the Convective Initiation tool would have helped us greatly. Figure 5 below shows the CI application combined with vis sat imagery. The algorithm picks up the CI very nicely…this storm eventually blew up and was one of the larger storms of the day. The storm produced very large hail.The UAH-CI application continued to be quite helpful to us during the rest of the shift.

AMA: Warn on CI “miss?”

Forecaster comments from EWP blog...

We have issued a couple warnings on marginal storms that did not give strong CI signals.  On this image, I warned on the middle cell in Hansford County (reflectivity on bottom left).  Note the lack of instantaneous or accumulated cloud top cooling for this area.  We are looking for downburst winds and maybe some subsevere hail from this storm.  The CI algorithms have been doing well in other CWAs like Lubbock, but may have missed one here, pending verification.

AMA: First potential UW/CI cell

Forecaster comments from EWP blog...

Here is the first cell that is close to -20C/15 min in the AMA area today.  Expecting storms to be mainly of the up and down variety due to lack of flow/shear.  Will be watching this one to see what happens.

AMA: Convective initiation in a non-supercell environment

Forecaster comments from EWP blog...

Kicking off the 4th week in the HWT at CWA AMA. Will be interesting to see how the convective initiation products handle more or less “popcorn” type convection beneath very weak upper flow and mid-level ridging. Image above shows several areas of moderate to high-indication CI in the next hour.