August 9, 2012 GOES-R FLS

This was my first exposure (shift) with GOES-R material (luck of the draw?).  Appreciated the lesson and learned a lot. I was impressed with the probability FLS image and comparing it to the older satellite images of low clouds/stratus.  I can see the utility with generating the TAFS...the FLS product will give me more confidence to go or not go with fog/stratus IFR conds.  The limitations at twilight were explained....makes sense.  Always great to have more tools at our disposal!

Some examples of the FLS probability product are shown in central Indiana. In Fig. 1, you can see a known characteristic with the cloud depth product, wherein the cloud phase product shows ice-based clouds "blacked out".  This is a result of the cloud depth product being limited to water-based clouds.  Also, note in Fig. 1 a swath of greater than 50% prob is located in east central IN. The nearest stations are showing CIGs of 110 and 95 hft and are outside this yellow swath.

Fig. 1. 1302Z: Cloud depth, IFR FLS Product, VIS Sat, GOES Cloud type(from top-left going clockwise).

In Fig. 2, the FLS product is now showing high probability of fog or low-level stratus.  However, the obs in the center of this high probability swath is reporting clear skies at 10 SM visibility.  Vis satellite was inspected and it reveals broken-overcast skies in this swath of high probabilities.  This was an interested feature given the initial discrepancies between the observations and the FLS product.  However, it was noted that the report of the obs was 1353 Z.  Wherein the satellite products have a time stamp of 1332. Thus, this is more so an artifact of this case (postmortem), where the observations and satellite products are not synchronized.  In a real-time situation, this is not anticipated to be an issue.

Fig. 2. 1332Z: Cloud depth, IFR FLS Product, VIS Sat, GOES Cloud type(from top-left going clockwise).

 In Fig. 3, the FLS product time stamp is 1402, which is now better aligned with this aforementioned METAR report at 13:53.

Fig. 3. 1402Z: Cloud depth, IFR FLS Product, VIS Sat, GOES Cloud type(from top-left going clockwise).

Further to the west, over the MKX WFO the GOES-R FLS IFR product performed well depicting the gradient in ceilings.  With low probabilities along a Madison to Milwaukee line; but increasing probabilities towards Wisconsin Dells  to West Bend.  Fig. 4 illustrates that the higher IFR probabilities to the north indeed matchup with lower ceilings, around 500 feet.  The ceilings over Milwaukee and Madison were 2700-4300 feet.

Fig. 4 1332 UTC Cloud depth, IFR FLS Product, GOES VIS, Heritage Fog GOES BTD(from top-left going clockwise).

To the northwest, the GOES-R FLS IFR probabilities captured a small, yet operationally significant area of low ceilings near and east of Fargo, ND  (Fig. 5).  The surface observations agree with the higher probabilities with 500-900 foot ceilings.

Fig. 5 1132 UTC Cloud depth, IFR FLS Product, GOES VIS, Heritage Fog GOES BTD (from top-left going clockwise).

It should be noted AWIPS @ MKX has been rolled back to an older version in preparation for upgrades to AWIPS-II.  As such, the products and enhancements are not current.

Ed Townsend - MKX
Rusty Kapela - MKX
Justin Sieglaff - CIMSS

EWP week 4 debrief

Today marks the end of 4 weeks of operations in the EWP.  Today we had the opportunity to debrief the forecasters on their experience here over the past week.

SATCAST / UW Cloud-top Cooling
- Yesterday's event over Boulder CWA... "We did try to warn on the CTC a couple times with ongoing severe to the north, the first storm quickly disappeared, but the second one was successful... we did get 1.5" hail out of it."
- "I can definitely see the utility of the products in focusing your attention on what is developing."
- "There were a couple instances where the SATCAST would have a lot of 'confetti', but there weren't any really strong signals... it really showed the utility of having the strength of signal instead of a yes/no."
- "The probabilities for the SATCAST did seem to match up with the overall occurrence of CI."
- "I may have only seen one case this whole week where the -20 C /15 mins signal in the CTC had any severe after it... I think there could be more work done to fine tune those values." - There seems to be some environmental dependance that could be playing a role in how successful the threshold values are in relating to severe weather... It has performed well over past weeks, but in some situations (like the past couple days) the occurrence of severe after a strong cooling rate may be less common.
- "I really liked that 'Ultimate-CI' 4-panel you guys had... that was nice... I would steal that."

Simulated Satellite
- "I found that the placement of convection was really good... the biggest weakness was the timing and the coverage of the storms... I see this as a 'top of the pyramid' product where I will start to get an idea of what's going on over my CWA."
- "It also picked up on the non-convective stuff (jet streaks/shortwaves) really well with the WV."
- "It would be great to get this in GFE."
- "I looked at the band difference, but I didn't really see the utility of it... granted I was more focused on the IR and WV which was more intuitive to me."
- "When we got set up, there was almost always stuff on radar, so we didn't really have much of a use for it."

Nearcast
- "I used it both as a forecast tool and an analysis tool."
- "A lot of the time this week the clouds were just too thick and made it hard to use."
- "I put the OUN WRF reflectivity on one panel with the CAPE and Theta-e products... the convection followed the CAPE/theta-e areas well... it was an interesting way to display it."
- "It was nice that you could use the GOES-E and GOES-W and overlap them to give you the complete picture... the values were a little different where they overlapped, but it still gave you a good picture."
- "It would probably be more useful in the early afternoon."

Sounder Airmass RGB
- "We ingest the other NASA sport RGB products and the color tables were so different for the airmass product that I got a little confused." - They were referring to the MODIS version of the RGB airmass, which does have some different color aspects.
- "I did look at it once and it did pick up on a lot of the larger scale features very well."

PGLM
- Yesterday's event over Sterling CWA... Had a lot of trouble with sensors failing over DCLMA and causing serious detection efficiency issues.
- "Like I said the other day... 5- and 15-minute composites would be great in addition to the 1-minute data."
- "The color curve was a little hard to see, especially for the lower flash amounts."
- "Lightning jumps aren't easily seen in the 2D gridded display... especially at 8km."
- "It would be really cool to see this over smoke plumes... we have seen some CG strikes from smoke plumes before."

Overall / Training
- It was reiterated that for some of these limited coverage datasets (ie - PGLM), it would be nice to have a map of the coverage.
- "The biggest negative was the satellite outage issue... it always seemed to happen right when everything happened." - 1800 and 2100 UTC are prime times for convection... and are also when 30-minute full disk scans occur.
- "Winds an turbulence are our biggest threats (CWSU aviation)... especially relating to non-convective weather and they are hard to pick up on with radar data alone."
- "I thought the change to having a training shift before you arrive was a great idea... it was overall very smooth."
- "I definitely felt more comfortable finding the products yesterday than I did day 1... It might be helpful to just sit down for an hour or two with someone and load the products."
- "Having procedures for the products really helped."
- "Having everything in AWIPS II was fantastic... we really got some good hands on experience with how the products will be used in the future."
- "I really liked the discussions with the developers... it really helped us understand how the products worked."
- "Having a level of uncertainty or confidence displayed within the products is very useful."

BOU: Another busy day for Traffic Management folks!

Forecaster comments from EWP blog...

Another day…same problem…convection firing up in the vicinity of some major jet routes and arrival gates in the DEN airspace. That means traffic headaches not only for controllers in Denver air space…but for people in ZKC, ZFW, ZAB…etc. You get the idea.

Once again, I’m able to test out the Sim Sat products. Already some activity firing up along the front range….but had I come in at 0530 (for a normal shift), I could have used the Sim Sat products to provide TMU with some good information for their planning purposes. Figure 1, below, illustrates the 19z Sim Sat compared to the 19z IR (lower left). You can see that the Sim Sat products have under-forecast the convection – one of the major limitations of the tool. However – the general location and trends are highlighted very well. With the exception of the development over BOU.

CYS: Convective Initiation and Impacts to Aviation

Forecaster comments from EWP blog...

Today is a great opportunity to test the Simulated Satellite products! I created a 4 panel to compare the sim sat products with the real time IR. I also overlaid jet routes to get a better picture of the potential impacts to aviation. One downfall to using the jet route overlay in AWIPS is that unless you’re familiar with the routes, you have no idea what you’re looking at. Maybe some day we can get a mouse-over feature with the jet routes so that the user can identify the names of the jet routes.

Figure 1: SimSat Compare with Real Time IR (lower left)

Figure 1 is the 4 panel comparison of the simulated products and real time IR. Figure 2 is the simulated IR and water vapor with jet routes overlaid. You can see that at 22Z, should the forecast be right, that re-routs will definitely be in order! I am eager to see how accurate this product is today…this could mean great things for the CWSU/FAA folks! Figure 3 is just a zoomed in 22z Sim Sat WV forecast.

Figure 2: 22z SimSat Forecast

The image in the lower right is the 10.4-12.3um IR which can help to show areas of low level moisture (yellow). As the column continues to moisten, you’ll see the areas of blue develop. Blue areas indicate a difference of zero.

Figure 3: Convective Initiation Forecast and BOU Impacts

Stay tuned to see how well the Simulated Satellite products work out!

OUN: An Aviation Perspective…

Forecaster comments from the EWP blog...

The image below (Figure 1) illustrates the potential for convective initiation, using the UAH-CI tool. The high altitude jet routes overlaid with the CI and latest satellite data show the potential impacts to aviation. I expect that the CI tool will be very useful in operations – especially at the CWSUs.

Figure 1: Convective Initiation Impacts on Aviation

TMU is always asking about timing and location of convective development. Things become problematic when routes need to be changed at the last second as a result of developing thunderstorms. If we have more tools to provide a larger lead time, TMU personnel can plan farther in advance – which leads to saving money and time…and stress!

MVFR-IFR Cloud Assessment - 3 Areas

The accuracy of the GOES-R probability of MVFR and the probability of IFR products were assessed in three areas across the U.S. and Ontario, Canada. This type of product will have clear utility in aviation forecasting, especially in areas where distance between surface observations is large, or if/when we lack observations due to communication failures.

Nebraska

The first area of concern was across Nebraska. This was an area of low clouds that formed in the wake of a departing convective complex early in the morning of August 30, 2011. Initially, much of the cloudiness was IFR (ceilings below 10kft,) lifting to a widespread MVFR deck after sunrise. The image below is around 1630Z, August 30, 2011. Upper left - MVFR Probabilities. Upper right - IFR probability. Lower left - Visible imgery. Lower right - Vis imagery with GFS 1000-850mb RH analyzed.



This product did a pretty job of placing high probability of MVFR across eastern Nebraska, but largely underplayed the existing widespread MVFR cigs over the central areas, especially around North Platte and points southwest where the deck was very solid. I suspect the holes forming in the overcast between the central and eastern areas were responsible for the more optimistic probabilities. But, subjectively, I don't believe these holes are near big enough to bring scattered conditions, or better than MVFR conditions. All of the surface obs across the area are bkn-ovc between 10kft-22kft.

South Carolina

The next low cloud area existed over the eastern/southeast half of South Carolina on the same day. The area of high probability (greater than 80%, red color) did a very good job capturing the existing MVFR deck. But, the MVFR deck stretched up into southeast North Carolina and the product appeared to become much too optimistic with the probabilities from northeast SC into southeast NC. Similar to the Nebraska stratus, this lower probability area had some holes in the stratus that appeared to be given too much influence. The surface observations throughout this lower probability were bkn-ovc from 21kft-26kft.





Ontario, Canada

This did a pretty good job depicting the existing MVFR deck south of Hudson Bay/James Bay on August 30, 2011. There was one, maybe two, observations in this entire area and these were limited to the far eastern portion. I suspect, though no way to prove it, that the clouds streaming in off of Hudson Bay were IFR, but then lifted into an MVFR deck farther inland. Similar to conditions that occur near the Great Lakes. A couple of curious areas were noted in this example. One, is the "weakness" in IFR probabilities (upper right panel) roughly in the center of northwest to southeast oriented stratus deck. We couldn't really find any discontinuities in other supporting satellite products. Admittedly, this is a very minor point. The other feature in question was the disparity in the very sharp southern edge to the MVFR deck as seen on the visible imagery and the large (stretched out) gradient in probabilities along this same edge. It appears the GFS 1000-850mb rh prog (cyan analysis in the bottom right panel) may have had a lot of influence on that.



In looking at all three of these examples, it appears to me that not enough influence is given to the current observations. This is a great product and has lots of potential for the operational environment.

Ideas for improving the CTC / OT algorithm for aviation forecasters

During the later half of this week in the aviation group at HWT, a couple of ideas were discussed for increasing the applicability of the OT, and maybe even more so CTC algorithms in short-term and nowcast aviation forecasting. I relayed the initial idea of incorporating a color scale and approximate value for cloud top height to the OT algorithm, which Steve Silberberg from AWC was very interested in, to Kris Bedka. Kris briefed me on similar products that exist or are in development that might be able to be implemented in AWIPS for use at the AWC. This would be used jointly with the UWCI algorithm to help identify "threat" convection.

Perhaps an even more applicable tool would be to include an approximate cloud top height or change in cloud top height between satellite scans with the CTC algorithm to quantify the actual vertical growth of individual convective updrafts. This could be extremely valuable to aviation forecasters in a short term / nowcast timescale for echo top forecast updates. Seeing a specific value for height change might be an even quicker assessment of cloud growth when combined with the CTC color scheme. Also, en route air traffic would be able to use such a tool to avoid rapidly growing updrafts prior to tops reaching 34000+ ft. This preventative measure would increase air safety by decreasing the probability of moderate to severe turbulence encountered by aircraft flying over cells with tops just below 340 due to the little knowledge pilots currently have of cumulus development outside of VFR. Both aviation forecasters this week expressed great enthusiasm for the advancements that such a product would bring to the aviation forecasting community including Brad Sherman from the FAA. To help familiarize the group with FAA operations, Brad explained how commercial aircraft usually fly over tops under 340 and "wing-wag" around those with 340+ tops. Learning about how flight delays and cancellations during the warm season rapidly stem from not only ongoing and developing convection, but also "snapshot" 21 and 23z 250+ convective top coverage forecasts made 4 hours in advance, was engaging to say the least.

-Dan Hartung

Using simulated ABI satellite imagery and UWCI nowcast product to produce 21z and 23z >40 dbz echo probability snapshot forecasts

Simulated band 13 forecasted ABI satellite imagery for 21z (bottom) and 23z (top) 02 June 2010.(Apologies for the backwards times)

This morning in the aviation focus group at the HWT, I encouraged the use of simulated ABI satellite data to guage an idea of the location of > 40 dbz echos initiated after 18z by the NSSL-WRF. Comparison of 14z B13 simulated ABI data to realtime GOES infrared imagery showed a fairly accurate representation of both intensity and location of the remnants of last night's MCS that moved through IA/northern IL, at the time extending from central MI through northern OH. However, second MCS remnants over northern MO were absent in the simulated data (See WV imagery in previous post). Therefore the outflow boundary and cold pool from the second MCS was not accurately captured by the NSSL-WRF and resulted in the suppression of convection along the weak cold frontal boundary that extended from east-central IL southwestward through MO / KS / western OK until 23z. One large positive result was that the NSSL-WRF did suggest initiation of convection along the outflow boundary from the then MI MCS along the KY/IN border by 21z.

The large stable cold pool that was left over central MO led us to forecast a moderate probability (50-74%) of thunderstorm initiation along the outflow boundary from the morning MO and MI MCSs along the MO/AR and MO/IL/IN/KY borders in agreement with the simulated ABI satellite data from the NSSL-WRF. Even though the simulated imagery wasn't particularly accurate in its evolution of the MO MCS event, the simulated mid-level water vapor channel (B10) was useful in identifying the location of mid-level vorticies over the southern plains and gulf coast during the forecast period. It was one of many tools that was taken into consideration when issuing a slight and moderate probability of convective initiation (> 40 dbz tops) over west-central TX and also over the LA/AL gulf coast for both the 21 and 23z 02 June snapshot forecast periods. As I'll make mention of below, convection in TX was initiated by 20z in the simulated satellite imagery which was at approximately the same time as realtime initiation. The complex appears to be evolving into an MCS as the evening progresses.

During the afternoon updates, the aviation team relied fairly heavily on developing trends in ongoing initiation over western TX and the southeast US as a whole for forecast modifications. We looked extensively at the performance trends of the UWCI nowcast between 18 and 20z. The algorithm performed very well and captured explosive convection over western TX with ~15 minute lead time. The convection was associated with a low-level meso-vortex dynamically supported by a sharp shortwave ejected from the AZ/NM border out over the southern plains shortly after 18z. Real-time water vapor and visible satellite imagery was critical in locating and tracking this feature from 13z onward.

A final thought, Aviation Weather Center (AWC) forecasters Steve Silberberg and Bruce Entwistle discussed with me their strong interest in installing the UWCI, CTC/OT, and simulated ABI imagery products in NAWIPS at their facility and I said I would relay their request to Wayne, Jordan and others.

-Dan Hartung

SATCAST within Aviation Applications

The GOES-R Convective Initiation algorithm being developed by the University of Alabama in Huntsville within the GOES-R Algorithm Working Group Aviation Applications Team. Nowcasting convective initiation is very important to aviation interests for airport operations and airline planning. If there is a good indication that a storm will develop 30 minutes to 1 hour, the airlines can plan for a particular aircraft takeoff/landing route to close causing an airport to reduce capacity for take-offs and landings or shutdown airport operations. The airlines would be able to hold back some aircraft at other airports, preventing a backlog at a particular airport and cause airplane diversions which can be costly.

In addition, knowledge of thunderstorm growth can help airport operators plan for the potential of lightning strikes and clear the ramp preventing any possible injury/deaths from lightning strikes.

There were significant airmass thunderstorm development over Illinois, eastern TN, and over the Atlanta area today. Below is an example of SATCAST over the Atlanta region which is a major Delta and Airtran Airline hub.

SATCAST Nowcast valid 1702 UTC

Radar valid 1709 UTC

Radar valid 1903 UTC

Radar valid 2000 UTC

Below are examples over the Ohio valley. Notice the convection which developed over central Illinois and around the southern eastern KY area.

SATCAST Nowcast valid 1732 UTC

Radar valid 1733 UTC

Radar valid 1811 UTC

Radar valid 1830 UTC