A Very Basic Mesoscale Analysis

I was checking out the NSSL-WRF Simulated Satellite Imagery compared to the actual IR Satellite and it verified pretty well.  You can see low clouds over parts of Iowa and Nebraska and the idea of the vertically taller clouds is there..just not exactly in the same location.  At this point I like the idea of the model.

So if I go with this model you can see below convection would initiate between 22-23Z over Central Iowa and S. Wisconsin bordering N. Illinois and then move East-Southeast.



This actually would be supported since the environment looks unstable that it is moving into.  You can see on the Nearcast GOES Vertical Theta E Diff Mid Low that the high instability is from Central Iowa to N. Illinois and it looks like a boundary is there as well.



So now we shall wait and see if this actually occurs. My watered down mesoscale discussion – Vollmar

NearCast and the MRMS

We have overlaid the MRMS combined reflectivity here and the theta-e difference for the storms developing in eastern WY. The storms appear to be developing in a region of the highest instability for the region indicating they could intensify as they continue to develop. It also indicates that the instability axis is fairly narrow.

-JB

NearCast Combined with Visible

Initial impressions today indicate that the NearCast model is providing additional confidence to what the visible satellite imagery is indicating. In the above visible imagery there appears to be a nice surfaced-based CU field from eastern NEb into northwest KS and then extending into southeast WY. On the NearCast model there is a ribbon of highest instability along this axis of CU as well.

-JB

EWP Operations Update – Tuesday 5/20

Our forecasters this afternoon are only four feet from each other in the HWT, but they are operating four CWAs apart in Cheyenne, WY (CYS) and Quad Cities, IA/IL (DVN).

Our CYS team is leveraging Super-Rapid Scan, LAPS domain placement from yesterday, and the potential for lightning detection from the few active Northern Colorado LMA sites in their diagnosis of convective potential and current analysis of developing convection in Albany and Platte Counties.

Super-Rapid Scan Imagery over WY from 1923z-1941z.

Our DVN team is performing a mesoscale analysis of the region around IA/IL/WI where the highest potential for severe weather and its associated hazards are expected. As destabilization is forecast to occur in the next hour or so, hopefully we will see some cells in this area by 22z.

EFP Day 1 Probability of Severe Thunderstorms

-Darrel Kingfield
EWP Week 3 Coordinator

Daily Summary: Week 3, Day 1 (May 19th, 2014)

Today started with such promise (or blind optimism…whatever you want to call it): an isolated region of “SLGT” risk encompassing parts of of SE Wyoming and W Nebraska with many storm-scale models showing isolated thunderstorm initiation around 21z. EFP probabilistic forecasts were focused in this area as well.

Day 1 forecast probability of hail. A 20% bullseye was located in the CYS and LBF CWAs.

Forecasters were situated in the Cheyenne, WY (CYS) and North Platte, NE (LBF) for the duration of the shift on the edge of their seats waiting for initiation.

We must realize that not all days will be “end of the world” scenarios, and today provided a great medium for forecasters to be exposed to several of the experimental product sets for comparative analysis and evaluation (sans OUNWRF).

Forecaster/Investigator interaction during the early evening on May 19th.

vLAPS was utilized to (1) identify and diagnose regions of enhanced instability (mainly CAPE) and (2) validate forecast composite reflectivity with MR/MS composite reflectivity. Throughout the day, comparative analyses of the NSSL-WRF simulated satellite imagery with real-time IR/WV fields were analysed. Any convection was immediately pounced upon with Super-Rapid Scan visible analysis, ProbSevere and Convective Initiation product analyses. NearCast was utilized to gauge storm lifetime and identify regions of destabilization.

The tracking meteogram was put through its paces today with numerous data dropouts observed in the time trend graph during periods were these data were available. Forecasters consistently wanted to use the 0.5 deg reflectivity mosaic product for tracking.

Near the end of the shift, total lightning from the Northern Colorado LMA was observed in Laramie and Kimball Counties in Wyoming which gave forecasters (1) exposure to the SPoRT LMA plugin and (2) guidance on how total lightning information can be combined with other sensor information (e.g. radar, satellite) in the storm interrogation process.

Flash Initiation Density and MR/MS Merged Reflectivity combination at 0024z.

Feedback (BL)

NearCast
- I found it to be pretty cool. I liked that you could see the areas of higher instability. When I used it in conjunction with pprob severe or ci I found it helpful to see if cu fiend is developing in area of higher instability or not
- I think it has potential. I am excited to see it

GOES-R CI
- It was very interesting in that it helped to tell you which areas not to focus on. Then I would go in and focus on areas with higher probs
- There were areas with no ci showing up that I thought it should
- Over relying on this product could catch you off guard. You need to be aware  of its deficiencies (under cirrus, etc)

ProbSevere

- It helped me focus in on certain areas

- I think I could use this on television, to tell viewers to focus in on this particular storm

- I like the annotation of moderate, strong, etc next to some of the parameters.

PGLM

-          - Total lightning towards the end of the day seemed to emphasize where the electrification in the storm was (something CG data sources to not show). 

Tracking Tool

-         -  It gave me a lot of problems. Gaps in the data (reflectivity)

SRSOR
- The one minute satellite data was amazing, I could sit it stare at it all day
- This is one of those products that we need yesterday
- It was nice to see details in in convective development

-Darrel Kingfield
EWP Week 3 Coordinator

Severe thunderstorm warnings in Wyoming and Nebraska

As we close operations at the HWT for day 1, two thunderstorms in Wyoming and Nebraska have been warned by the NWS (see figure 1).

Figure 1: NWS warnings at 7:12pm (west warning) and 7:15pm (east warning)

The ProbSevere had over 40% on each storm (40% and 46%, respectively) when they were warned, owing to large effective shear, MESH around 0.7", and moderate satellite growth rates (figure 2). These have been some of the highest probabilities we've seen today, and ProbSevere tends to underforecast somewhat in low-CAPE high-shear environments, so 40% may signal to the forecasters as a storm to watch. Each storm produced 1" hail shortly after the warnings (7 min and 3 min later), which were issued at 7:12 and 7:15pm.

Figure 2: ProbSevere contours at 7:12 pm. The two storms to become warned exceeded 40% probability of severe.

-Cintineo

NLDN vs. PGLM Analysis

 This is what I am used to looking at when talking about lightning to viewers.  These are just cloud to ground though.

The PGLM Total Lightning shows you the “spider web” of the lightning strike, a much bigger area spatially then the particular point on the ground the bolt hit as you see below.  It will definitely help me warn viewers ahead of time that there could be lightning in there area before it actually hits the ground.  Great Product!



I haven’t been able to us the lightning jump detection to see how that does.  Hopefully later this week. ~ Danielle

Flash Extent Density vs. Reflectivity

Overlaying the 0.5 km MSL composite merged reflectivity with the flash extent density showed some interesting things. The image below shows a positive correlation between flash extent density and reflectivity.

As the flash extent density increased, the reflectivity increased as well, which can be seen from the meteogram. Furthermore, the increase in reflectivity appeared to be a response to the increase in flash extent density. For example, flash extent density displayed an increase in its value while the cell of interest still had relatively low reflectivities (<= 30 dBz). In the successive image of 0.5 km MSL composite merged reflectivity, a large increase in reflectivity was observed. Additionally, the max reflectivity of the cell seemed to approximately follow the max in flash extent density, with the location of max flash extent density remaining slightly out ahead of the location of max reflectivity.

Lightning Flash products possibly useful for more than severe weather.

This image is displaying Flash Initiation Density and Flash Extent Density in addition to the typical 5 minute lightning plot.  What stands out here is that larger areas of the storms are more electrified than viewed by just the 5 minute lightning plot.  This helps the forecaster determine better what the arrival times to use when they are considering TS or VCTS for amendments to TAFs or may help in giving a better ETA of lightning for large events such county fairs for emergency managers or spot fires other IDSS customers.

Side-by-Side with GOES-14 SRSOR

Having one minute satellite data available to be able to see the finer details of storm evolution/de-evolution is one of those products that is incredibly helpful. In the screen capture below, you can see a side-by-side picture of the traditional view of visible satellite data only being updated every 15 minutes (with a longer lag time to actually ingest the product for viewing) on the left and super-rapid scan on the right. Between 2245Z (left) and 2258Z (right), you can see what has occurred near the WY/NB border in just a 13 minute time period. While not terribly significant with this evening’s weather activity, it is still noteworthy and I can only imagine the cloud features that we’re missing to indicate storm development and trends without SRSOR.

~Linda