Something to Watch Charley

Have a new CI ping, 70-80% in Fall River county.

Looking at the Nearcast model, have a little peak that bends down to that point in the county.  Will have to watch to see if we get new development there.  It is a little drier down there, so wonder if a storm that forms here may have better mix down of winds.

UPDATE:  That cell did not develop, however we have another high CI signal later, here:

Nearcast Model Aides in Forecasting Severe End Time

The Nearcast model vertical instability product had cloud/missing data issues, but still was able to provide some good timing on the eastward progression of the front through the Morehead City forecast area. Note the light blue pixel area (unstable), albeit only a small group of pixels, shifting east in the loop below.

This timing can help with severe weather staffing at a forecast office and with DSS messaging to customers.

Rocky

Nearcast Vertical Instability 00hr Useful in Nowcasting

Using the very early time steps in the Nearcast model has again proven useful for depicting the area of storm development today. The area of most robust storms matched the greatest dThetaE/dz seen in the Nearcast model. Notice also the stability seen further west in the post-frontal environment.

Rocky.

Storm Develops in Nearcast Model Vertical dThetaE Max

The good: The initial storms of the day in the Midland, TX forecast area formed in the Nearcast model most unstable differential thetaE depicted in the 0-1hr forecast (see the Nearcast+Radar+Visible image below).

The bad: Because my forecast area (San Angelo, TX) further east had prolonged morning clouds (see 14Z Visible image), the retrievals could not be accomplished and the instability trends in the Nearcast model through 9 hr were not available.

Rocky

Nearcast Model Aids Destabilization Situational Awareness

In assessing the Midland, TX forecast area destabilization forecast, the Nearcast model differential theta-e product provided a good visualization of the next several hours. Low-level southeasterly flow over srn TX was forecast to bring higher dewpoints (10-12F) into the srn Midland TX forecast area through the day. The Nearcast model provided another opinion/visualization of the advective process, as well as both the relative magnitude (geographically) and the northern extent of the instability through 02Z.

As a forecaster, this 1) added to the confidence of destabilization 2) allowed me to better visualize the 3D atmospheric changes expected on this day and 3) concentrated my SA to the srn forecast area.

Rocky Balboa

Week 4 Summary and Feedback

Below is feedback from our final, week 4 weekly debrief session, along with a photo of the week 4 participants.

This marks the conclusion of the GOES-R portion of the 2014 HWT Spring Experiment!


- Bill Line, SPC/HWT Satellite Liaison

Simulated Satellite Imagery:
- It’s great to use the imagery to evaluate model performance.
- Had issues with burning off low stratus too early, leading to errors with heating during the day and errors of convection timing
- Do you see simulated model imagery being useful in forecast environment; would you like to see this data with other high res models?
    o All say yes, it is useful and would like to see it with other models (hrrr, etc)
    o Higher res models might pick up more discrete features things
 - Easy ways to pick up on errors in the model

Nearcast
- I used it mainly for ted and pw, it almost shows this better then anything I have in my office
- Nice to have in awips to overlay other things
- Helpful to show where boundaries will move, areas that are moistening
- Best as a precursor, ~3 hours prior to ci mostly
- I like the fact that you could really key in on boundaries, and I saw convection go there.
- Even subtle gradients up in high plains, small increases in ted, see showers pop up
- In Raleigh, having a tool that may easily show boundaries, esp in spring and summer, it could help
- I see more utility in theta-e and ted than in the PW field
- Calibration issue, we are used to looking at CAPE and LI. What does the ted values mean? Is there a way to do this?
- Its real-world information, which is good
- Overlayed forcing parameters on it.

Ci
- Didn’t increase my confidence as much as I had hoped
- One cell I tracked for a while in Huntsville area, had pretty high value, that did go up and eventually became strong
- Get rid of lower values

Probsevere
- This is especially useful for more slowly developing convection. Storms that look the same may have different probs, pointing out which storms are actually more threatening,
- Not as useful when convection is rapidly developing. The 1-2 scan lag hurts
- Good as a confirmation tool even for mature convection
- Good for slowly developing storms, detects hail well, poor with wind, not sure with tors. Prob severe hail may be better name. Rapidly growing convection, it wasn’t as useful with lag (1 volume scan), which hurt.
- Broadcaster – I really enjoyed this product. I am doing a lot during a day, especially severe day, it pinpointed where I should look. Same with CI
- Right now, as a regional SA tool, storms coming in from neighboring CWA, would be good to watch. Also for updating warnings.
- Column velocity to determine wind threat,
- Seems like product that has room to do some interesting things.
- with prob severe/hail/wind/tor, have a 4 panel, with total severe and 3 threats. Different parameter underlaid each

Overshooting Tops
- Broadcaster – really useful for me, in busy environment. I can speak for every broadcaster, we’d all love to have this product.
- More utility at night than during the day
- Helpful to CWSU cause I'm looking at a much larger area

Tracking tool
- This trend information is beneficial to have.
- Probably best for warning coordinator, or for research purposes. It is high maintenance, takes a lot of work to use

Lightning
- Broadcaster – lightning is especially useful for me, the chopper folks are constantly asking me where there is lightning to decide whether it is safe for them or not
- Most useful for rapidly developing convection
- Any time a jump occurred on a storm, the dBz’s would spike soon after
- I think it is everybody’s favorite thing, the lightning
- Most helpful for a warning operator, everything else was more SA.
     o Mostly because we had information every minute.
     o Getting additional info while we are waiting for next volume scan
- It impacted my warning decision making process.
- Especially useful in rapidly developing convection
- Broadcaster – lightning is very important even if it isn’t severe
- I wish I had more time to look at it.
- Training for lightning is not that good, to understand more why/how this is working, would be helpful. Why in certain environments and situations would it not work so well. But why better in others
   o Explain what is going in and why it is working

Broadcaster – from this perspective, most of the products demonstrated make it easier for him to do his job, because he can easily spot where a new storm is coming up in busy situations, where lightning is increasing. It helps make things easier for everyone at station.

CWSU – CI and OTD would be most useful for me, covering a broad forecast area. OTD quickly shows me where the strongest updrafts are, and ci highlights where convection is initiating or most likely to initiate in the near future. Also, lightning data is valuable for me.

General – be cautious of data overload. Products have to quickly prove their worth and utility in operations. Some products might be more useful for a warning coordinator, while lightning and maybe prob severe could be helpful for radar operator

Overall
- 1pm briefings from EFP, is there a reason for us to be in on that. A lot of it was not important
- Even from the briefings, I had no idea what was going on. It seemed more like a debrief for themselves. It had no application to us, it was geared to the efp
- I could have better spent my time making myself aware of the meeting.
- Schedule our debriefing during that, and maybe have it earlier (noon)?
- Since a lot is pre convective environment, we should come in at 9 or 10 to start.
- To be able to look at these products with other convective modes would be useful too.
- Broadcaster – recommend others to get with local wfo and get a couple hours in front of awips. Simuawips helped quite a bit.
     o This is most fascinating week of science I've had in a while.
     o Very much against working with just broadcasters in the hwt, found it very beneficial to be here with nws mets.
- All forecasters gained, learned from each others unique perspectives. Against segregated experiments.

ThetaE Difference Loop – Showing Increasing Instability/Convective Potential???

Attached loop shows the Theta E difference values decreasing over the front range over the last 2 hours.  Looks like a minor surge of moisture creeping northward – which if this is correct should increase convective vigor by 21z.  This appears to be happening already – with storm intensity increasing on radar between 2000 and 2015Z.

Fowle

NearCast ThetaE Diff

Examined the ThetaE difference at 19z.  From a qualitative perspective – the ThetaE difference is greater over PUB than BOU.  Thus – you would expect it is more unstable over the PUB CWA – and thus more vigorous updrafts.  We shall see how this verifies this afternoon.

Daily Summary: Week 4, Day 3 (4 June 2014)

Today, we operated in 4 county warning areas:

Team 1 (Fowle & Anderson)

Louisville, KY
Springfield, MO
Cheyenne, WY
Team 2 (Pelczynski & Satterfield)

Boulder, CO
Early in the day, it appeared that the greatest severe threat would exist in the MS/OH valley region.  Additionally, there were enough breaks in the high-level clouds to allow for use of the GOES-R satellite products.  However, as the day progressed, it became apparent that the region would not destabilize as much, so we moved Team 1 to Springfield, MO (based on a favorable mesoscale discussion).  As it turns out, the capping inversion would hold over that area.  Thus, we moved Team 1 to Cheyenne, WY – hoping that we could catch some lightning data from the LMA in Denver.  A few marginally-severe storms did develop.

Team 2 remained in Boulder all day.  There, they used the GOES-R products extensively, including the NearCast, UAH CI, Probability of Severe, and lightning data.  Several severe storms developed, though only one severe report was officially logged (for a landspout tornado).

-G. Garfield
Week 4 Coordinator

*** Day 3 Feedback (Bill Line): ***

Simulated Satellite Imagery
- Spot on yesterday. As far as overall timing and development, it was really good. The fact that it picked up on little features early gave me confidence in the rest of the forecast
- Not as good in Missouri area.
- Burning off stratus too quickly seems to be a recurring issue with the model

Nearcast:
- I liked it yesterday, particularly because as we sat down there was convection getting going, related to theta-e diff gradients, you could predict where they would move based on the nearcast forecast.
- We looked at it for a good 2 hours
- Theta-e values were pegging where it finally developed in far northwestern NE

Goes-r CI
- Looked at in with the other products in the 4 panel
- In Kentucky, it was bubbly, weak CIN,  a lot of low values that jumped around, noisy field, didn't see values over 60%
- It triggered on a few but we were already on them.
- Might be better for larger areas of monitoring (larger than CWA)

Prob severe
- Sometimes it is a nice confirmation of what we already concluded
- With rapidly developing convection, storms went severe within a few scans, prob severe lag kind of hurt it
- With gradually developing storms, it may be more of a confidence builder to issue a warning
- In broadcast world, this is valuable in pinpointing a storm to look at
- One went 16 to 60 in one scan, making me look at the storm
- In Louisville, a lot were hanging in low range, it told us what environment would be like that day, very low end, bubbly stuff
- The values it showed us were helpful (predictors) to see
- Satellite ingest made a huge difference (with satellite data compared to without)
- Tells us what is the trend of the day, perculating stuff, or fast growing
- With trends it was somewhat helpful with dissipating storms, you could see that chances of it being severe were becoming less. Caused me to look at it more
- There was a lag between when I issued a warning based on prob severe and when NWS finally issued

overshooting tops
- I can see, with mcs’s, having this info is useful, you can see where stronger storms are in a complex, you have a long line, key in on these areas.

Pglm and LJ:
- I could see reflectivity increase 15 to 20 min after lightning jumped up. Tracking tool helped me see this. I think both of them together is valuable
- The lightning jumps led to me quickly issue a warning with rapidly developing storm in boulder.
- I used just lightning data to issue warnings,
- Using FED in conjunction with LJ was a red flag that storm was rapidly increasing in strength
- I thought it was really good yesterday
- LJ- I find it useful and like being able to see when it jumps,
- Option for max LJ over last 5 mins would be great. Still update every minute though. (Running max). So that I don’t miss an LJ in the rapidly updating product.

Tracking Tool
- I like the idea and concept of it, compare trends in fields and different storms. But there are a lot of problems
- Looks like I have to load all products first, then load  tool
- I crashed my system
- Very handy with lightning and reflectivity
- May be more useful to look back at archive data. Research tool
- In real time, it takes too long to work, you don’t have that much time. Maybe just the warning coordinator
- Its not telling you a lot different than what you can see

theta-e ridge

The upper left panel clearly shows a theta-e ridge lifting north from NE CO into SW NE where convection is expected to fire close to 00Z. Stepping through this image clearly show the ridge lifting north indicating a new threat area of possibly severe convection.

jca

my ideal SA display

This 4 panel would be an ideal SA display for forecasters not only as convection is on-going (a non-radar operator), but also as a nowcast tool. We are looking at theta-e difference, CI, sat with overshooting tops and sfc obs, and radar with prob severe.

jca

SA for SGF ops Wed

With a cap still in place, we are seeing where convection should fire based on the above images. The theta-e difference shows a clear instability gradient along a slowly moving cold front. The CI is showing increasing values along that same line as supported by the visible satellite pic.

jca

X marks the spot!

We are seeing convection firing near the intersection of two boundaries (pointed to by the red arrow)…the gradient in theta-e difference from the nearcast product, and a west-east oriented line of cumulus shown in the visible satellite imagery. The METARs, circled in blue, show convergence of dry downslope winds and relatively moist upslope flow in that same area where the boundaries intersect. If the simulated IR imagery for later this evening is any indication, this line of cu will slowly slip south and east…with strong convection firing in its vicinity east of the CWA later this evening.

-KP

-D. Satterfield

Showers going up in a favored area

This image shows the convection trying to get going in an area along a dewpoint gradient, denoted by the dryline symbol, and in the vicinity of the nearcast gradient in theta-e difference. This is the area we were focusing on based on both the nearcast forecast and the simulated IR imagery from earlier. Expect this to continue to be a favored area…with a potential shift eastward throughout the afternoon.

-KP

-D. Satterfield

HWT Wed 4 June blog 2

Theta difference and surface based cape analysis over central  and North CO. We can see a well defined theta e diff boundary and this is collocated with a SB Cape boundary as well. Some small convection is developing along these boundaries. LMA seeing some very low numbers of CG on cell near CYS,

Theta E diff continues to be valuable in locating boundaries where convection will develop. Better than even using SB Cape by itself. Over the last few days convection seems to develop near these theta e diff boundaries.



D Satterfield

KP

Convection firing along Theta-e diff boundary from the near cast

The red boundary drawn in the circle shows the area where convective initiation is taking place, which is co-located with a gradient in the theta-e difference off the nearcast. Also, as shown in the obs plot (bottom left pane) there is a sharp gradient in dewpoint across that boundary as well, ranging from around 10 degrees with downslope winds off the mountains, to 40-50 degrees and an upslope wind on the east side of the boundary. This appears to be a favorable area for convective development and will continue to monitor throughout the day.

-KP

nearcast wed over kentucky

You can see the gaping hole over Kentucky in this nearcast analysis due to extensive cloud cover from earlier convection. Trends are pretty much impossible to detect at this time.

jca

Daily Summary: Week 4, Day 2 (3 June 2014)

A strong short-wave trough moved through the Central Great Plains, generating severe thunderstorms in a strongly unstable and sheared environment.  During the event, we operated in two CWAs: Hastings and North Platte.  Forecasters Pelczynski and Anderson operated in Hastings; forecasters Fowle and Satterfield operated in North Platte.

When we started operations, convection had already begun in NC Nebraska, and it began to grow upscale as the sytem moved toward Omaha.  Further west, convective initiation held off for some time, before multiple storms fired along the warm front that stretched across central Nebraska.  A supercell near Ord, Nebraska became tornadic, and produced multiple tornadoes along its path just south of Omaha.

However, as the cold pool north of the warm front strengthened, it became increasingly clear that a major tornado event would not occur.  At the time of this writing, however, it appears that a significant wind event may still occur in eastern Nebraska into southern Iowa / northern Missouri (per the SPC high risk).

-G. Garfield
Week 4 Coordinator

Feedback (BL)

Simulated Satellite Imagery
- A+ on that. Model missed convection because it had a cirrus shield that wasn't actually there. So the model  likely developed convection late because of this.
- Gives me confidence in the model. from a big picture standpoint, I think there is some utility there for forecasters
- Even if it didn't do the best, its still important information
- Suggestion – fade in out reflectivity

NearCast
- I liked the theta-e diff and pw plots. Good for getting idea where you may start seeing convection get going, particularly where there were strong gradients. Using current vis with nearcast forecast, I looked for where would fields interact with boundaries in the near future.
- Gradients are helpful, qualitative area where you want to investigate further.
- Even with data dropouts, you can infer.
- Its good in the pre-convective environment, going into event. Once warnings get going, kinda stop viewing it

GOES-R CI
- For us, there was a lot of cloud obscuration, from high cirrus, for storms that were obviously going
- There were areas where you could see ci increasing for successive volume scans where showers developed
- It did pretty good in showing areas along line that would develop
- But doesn't give much info on whether developing convection will become severe
- We use ctc in our office, I find that to be more useful. You don’t get a lot of noise, it just gives you cells that are growing the quickest. It provides what storms are growing, and gives quantitative value of that developmental rate. That to me is much more useful than ci product. It doesn't hit every storm, but I like that quantitative info it gives. We pay attention to the -10, -20 -30 thresholds.
- Broadcaster world very much use this – something that tells you where to pay attention is valuable. Every broadcaster would like to have the ci.

ProbSevere
- I thought it was useful – times when you had big jumps up and down, which is good to know. Good safety net, gives you clues on which storms you need to pay attention to. A little more calibration on some of the thresholds might be needed. Seems like its more of a hail predictor.
- For wind – temp-dew point depressions, sub cloud evaporation. Which will be wind producers.
- For situational awareness, if I'm on air, prob severe would be very helpful for me (broadcaster), esp if I am only one in at the time. If I can see quick prob severe on another cell, it would lead me to look at it
- Color curve, I struggled with near 10% and 40%, they looked similar.
- Once it becomes severe, it doesn't do you much good anymore, there are a lot of other products that could tell me its decreasing, etc. Once its mature or producing severe, maybe make it a different color or something
- For a colorblind person, it could be difficult. perhaps get thicker with lines as you go up (moreso than is already done).

OTD
- I think its most useful to see when tops are dying.

- I think with 5 or 1 minute data, this would be more useful, especially at night

NearCast – Evolution of ThetaE Difference

The ThetaE Difference product appeared to provide good guidance on where convection would develop.  As has been shown in the past, the gradient in the ThetaE difference product is where most of the action took place.

1930Z:

 2030

 2130

 2230

 2330

2152Z OT Tops 3 June

at 2130 the OT Top detection did pop up on the cell to the SE of our area today. Bottom right in the two right windows. Have seen what looked like an OT on this for at least 30 mins. but it was rather ill-defined… can see why the OT had trouble with it. Has 99% POS and has for at least 30 mins. The POS has been more valuable with this storm, while the OT has not been as helpful as I expected today. It is however very helpful in keeping track of the most severe storms, which is of course one reason it was designed for.

DSatterfield