Welcome to Week 2

Good afternoon and welcome to week 2 of the HWT Spring Experiment!

We've got a whole new batch of forecasters this week coming from all over the nation; Cheyenne, Grand Rapids, Charleston, New York, and Norman. Today will focus on getting these forecasters spun up with each of the products and slowly ease them into the warning process. We'll be centering on CWAs in the northwestern portion of the U.S. this afternoon as the rest of the country is fairly quiet. This rather docile weather pattern looks to stick around for at least the next several days, making it a quieter but hopefully still productive week.

As mentioned last week, the 'Tales from the Testbed' webinar this week will not be GOES-R focused; instead it will be looking at either EFP collaboration or HSDA and MRMS applications (depending on the weather). However, keep an eye on the blog throughout the week as forecasters will still be looking at and evaluating all of the experimental products at their disposal.

And now, without further ado, let week 2 begin...

EWP/EFP collaboration briefing - focusing on the NW U.S. for the first day of week 2

Simulated ABI imagery in the EFP

Today's focus area for convective initiation extended from eastern Iowa to central lower Michigan.  Although the forcing was adequate for deep convection, the low-level moisture was marginal with surface dew points only in the upper 40s so that the instability was weak.  Based on the ensemble model output (SSEO, AFWA, CAPS), the area of greatest likelihood for convection was located across northern Illinois, southeastern Wisconsin, and central Michigan.  The location of these thunderstorms if they were to occur would have a large impact on air travel through Chicago.  Most of the ensemble members predicted that convective initiation would occur between 21 and 23 UTC across this area.  The NSSL-WRF model, however, had the main convective area further to the west and was the most aggressive with the convective development across eastern Iowa, northern Illinois and southwestern Wisconsin.  The initiation and subsequent evolution of the simulated thunderstorms was clearly depicted by the CIMSS synthetic ABI imagery.  The simulated ABI visible imagery was also useful for depicting these thunderstorms.

When preparing the convection forecasts in the morning, the NSSL-WRF model solution was discounted given the tendency for the ensemble members to prefer convective development further to the east; however, as of 22 UTC, it appears as though the NSSL-WRF solution had a more accurate depiction of the convective development.  The images below show a comparison of the simulated ABI and real GOES infrared channels across the central U.S from 21 UTC.  Notice that the linear band of deeper convection across eastern Iowa and southwestern Wisconsin in the synthetic ABI imagery agrees well with the real GOES imagery.

- Jason Otkin

EFP simulated satellite evaluation

Part of this year's EFP portion of the Spring Experiment is to examine simulated satellite imagery from the CAPS ensemble.  The goal of this project is to determine how differences in the microphysics schemes in the different model runs produce different cloud objects and features in the simulated imagery.  While this is not directly related to GOES-R, it is exposing the modeling community to satellite techniques and radiative transfer.  The group asked me to help them explain why different clouds seemed "cooler" in the simulated imagery and how features of clouds (such as ice particle concentration, height and optical depth) would affect what an actual satellite would "see".  I was able to alleviate some confusion amongst the participants regarding whether the standard IR window was seeing a layer or more of a surface when it came to different cloud features, such as an optically thick storm updraft core versus a relatively optically thin cirrus cloud associated with an anvil.  It is good to see some of the non-satellite community actively trying to better understand how satellite observations are made.

EFP CI and Severe desks

EFP CI (left) and severe (right) desks during the morning forecast period.

This year's Experimental Forecast Program (EFP) contains two main focus areas... convective initiation (CI) and severe. Both desks are using experimental high-resolution numerical models and ensembles of those numerical models (CAPS ensemble, SSEO, AFWA) to forecast the first occurrence of a 35 dBZ radar echo (CI) and the subsequent severe weather. They will be examining some of the simulated satellite imagery and unique GOES-R band differences during their forecast operations that we provide them from the NSSL-WRF 0Z 4km model, as well as from some of the members of the CAPS ensemble.

Nearcast training for severe

UW-CIMSS scientist Ralph Petersen explaining the Nearcast product to EFP participants
This morning UW-CIMSS scientists Ralph Petersen and Bob Aune sat down with the EFP's severe desk to help train the participants on how to use the Nearcast product during morning forecast operations. UW-CIMSS provides us with 10 fields from the Nearcast product, which includes individual layers of theta-e and preciptable water (PW), which are then differenced to provide the differential theta-e and PW water fields that we typically use for forecasts. The most effective way to help forecasters understand what they are looking at in these differential fields is to start with the individual layer PW and theta-e fields and then the forecaster can mentally calculate the differences and compare to what the product is showing them. Ralph and Bob helped the participants understand how the Nearcast can assist them in making their forecasts by pointing out that the Nearcast fields will show you where relatively convectively stable and unstable areas are. Because no forcing mechanisms are included within the Nearcast's output, it doesn't guarantee where convection will occur, but it can help narrow down where you should be focusing your attention. If there is an area of strongly stable air, you're not likely to have any deep convection, even if there is some sort of light forcing present. This may be especially useful within SPC operations for forecasters issuing mesoscale discussions (MD) to determine where a severe thunderstorm or tornado watch will or will not be needed. It may also be useful during the early afternoon convective outlook updates to help trim areas that will not be expected to have thunderstorms later during that day. Following the group training, Steve Weiss (SPC SOO) asked if I would be willing to work with the forecasters in operations this summer in exposing this product to them. In addition, we expect to provide a training session within the SPC's bi-annual forecaster training this fall to help expose all of the SPC personnel to the product.

Final week of the experiment...

Today marks the first day of the 5th and final week of this year's Spring Experiment. This week the EWP rejoins the EFP from its week off and resumes normal activities. Today the EWP will be providing forecasters with a load of training material as they prepare to use the experimental products during real-time forecast/warning operations. Following the 4-hour PowerPoint session we will have the forecasters work through a WES case to get familiar with where the products are, what they look like and how to use them within their AWIPS workstations.

UW Nearcast Product and Developing Convection

The GOES Sounder Nearcasting product is being used today on the EFP CI-desk to identify possible forcing mechanisms for the deep convection. In the image below the nearcasting theta-e difference is shown, valid 1700 UTC 01 June 2011. Strong convection has been ongoing and continually developing in eastern to north-central Kansas along the minimum (maximum instability) and northeastward toward the strong gradient in the nearcasting theta-e difference. It was noted this gradient is also coincident with a strong dewpoint gradient at 850 hPa. It is believed southerly flow across this gradient is helping force the convection. Further east across the Mid Atlantic region, convection was developing largely in the minimum of the theta-e difference, with a strong gradient to the west as low-level moisture decreases behind the front. It has also been noted there are many other areas of strong potential instability indicated by the nearcasting product, however there is not deep convection associated with many of these areas. One hypothesis is there needs to be not only instability present, but also a forcing mechanism. Possible forcing mechanisms maybe inferred by a strong gradient in the instability indicated by the nearcasting product, suggestion strong temperature and/or moisture advection.

NSSL-WRF Simulated ABI Imagery and CI forecast

This morning on the EFP CI-desk, the simulated ABI imagery from the NSSL-WRF provided guidance on location and timing of initial CI location for many of the forecasters. As can be seen in the image below, there was a tight cluster of forecasted first CI location points over the higher terrain of northern New Mexico. The simulated ABI band 13 image valid at 1900 UTC shows newly developing convention over northern New Mexico. A few other forecasters favored convective initiation along the moisture gradient in the lower troposphere in eastern Kansas. (Ongoing storms northwest of Salina, Kansas were excluded from the forecast area.)

Simulated ABI Radiances Compared to GOES Observations

This week there is no EWP running so all support is geared towards the EFP. Early Tuesday on the CI desk of EFP, the NSSL-WRF simulated ABI radiances were compared to the current GOES observations for judging the timing/placement of the upper level vorticity maxima/upper level dry intrusion over the Central US, as well as impact of cloud cover on convective intiation forecasts over the western Great Lakes.

Below are the 15 UTC simulated ABI brightness temperatures (top) and observed GOES brightness temperatures (bottom). The consensus of the forecasters on the CI desk was the NSSL-WRF had excellent placement of the upper level vorticity as depicted by the water vapor channels. On the other hand, the NSSL-WRF struggled to capture the intensity and magnitude of a band of clouds and decaying convection over the Upper Mississippi Valley/western Great Lakes. The images below show the GOES observed clouds are much more expansive and have colder brightness temperatures than the simulated ABI clouds from the NSSL-WRF. Discussion is ongoing on how these clouds will impact convective initiation timing and location later today.







FLASH utility to toggle between images

NSSL-WRF simulated GOES-R products

GOES-R visiting scientists discussed with NSSL scientist Jack Kain about the possibility of creating NSSL-WRF simulated GOES-R convective initiation products. Since the model has very short time-steps (24 seconds), following cloud 'objects' via the SATCAST overlap method should be relatively simple. From this, a cloud top-cooling rate and other CI fields, such as cloud-top glaciation, would be easy to produce. Hopefully in the future we may be able to start producing this and other unique GOES-R products that we can not currently produce from observational sensors.

Simulated GOES-R band differences

As part of the EFP CI desk's morning forecasts, they asked me to demonstrate the NSSL-WRF simulated 10-12 micron band difference provided to us by CIRA. Neither of these channels are currently available together on our operational GOES satellites and will be available on the GOES-R satellite once it launches. One of the advantages of simulating satellite data from a model is that we have the opportunity to produce channels that we don't have currently, and we take full advantage of this by producing all 9 of the non-solar GOES-R IR bands. The 10 micron channel is a very clean window, and thus is very sensitive to surface temperature. The 12 micron channel however is sensitive to low-level water vapor. As moisture moves into a clear pixel area, the 12 micron brightness temperature will decrease, whereas the 10 micron temperature should stay the same. When this occurs, the 10-12 micron channel difference will become strongly positive and indicates areas of moisture convergence or pooling, which can lead to destabilization and subsequent convective initiation. Below is a collection of today's notable images, with signals of moisture pooling and destabilization shown in yellow and orange colors...

NSSL-WRF simulated 10-12 micron band difference for 1600 UTC (top), 1900 UTC (middle) and 2000 UTC (bottom) on 24 May 2011.
At 1600 UTC (top image above), we can see that the channel difference is showing an area of low clouds (blue/green colors) beginning to dissipate over central Oklahoma. At 1900 UTC (middle image above) these low clouds are completely dissipated and we can start to see some development of pooling moisture along the dryline in W. OK and the triple point on the OK/KS border. By 2000 UTC (bottom image above), storms begin to initiate near the triple point and values in the channel difference become strongly positive just south along the dryline.

NSSL-WRF simulated 10-12 micron band difference for 2200 UTC on 24 May 2011.
At 2200 UTC (image above) additional convection develops on the southern part of the dryline in central OK and into TX. It is interesting to note the presence of linear bands of enhanced moisture pooling where the convection develops ahead of the dryline. It is theorized by the EFP CI desk participants that this may be signals of horizontal convective rolls within the model leading to areas of enhanced convective potential. This demonstrates a very interesting tool to help aid forecasters in the prediction of convective initiation and also a unique combination of satellite and model information.

Examining NSSL-WRF simulated imagery/lightning

Observed (top) and simulated NSSL-WRF (bottom) WV imagery for 1300 UTC on 24 May 2011.
This morning EFP forecasters and scientists examined the simulated satellite imagery and lightning threat products from the NSSL-WRF. One of the most useful aspects of creating simulated satellite imagery from a model is the ability to compare the output directly to observed satellite imagery to determine model performance, as well as being able to have a one-stop 3-D representation of the model produced atmosphere. At 1300 UTC we matched the simulated GOES-R band 9 (6.95 micron) to the observed GOES-13 WV channel to determine model performance for the day. As you see from the images above, the model atmosphere and the observed atmosphere are very similar. The model correctly identifies an MCS over N. KS and on the KY/TN border. It should be noted that the model's simulated cloud tops generally appear to be smaller and less extensive with the cirrus shields. The position of the mid-level jet streak is also very similar, as seen in the deeper red colors extending from AZ/NM/TX panhandle.

NSSL-WRF simulated lightning threat for 2000 UTC (top) and 0000 UTC (bottom) for 24 May 2011
The NSSL-WRF initiates storms between 1900-2000 UTC along the OK/KS border. The simulated lightning threat imagery (seen above) provided by Bill McCaul (USRA) provides us with an estimation of total lightning flashes. At 2000 UTC (top most image), we see the first isolated storm along the border, with total flashes per square kilometer per 5 minutes reaching a value of 5. At 0000 UTC (bottom most image), we can see the extent of the storms across most of OK along the dryline. At this time we can see flash rate values reaching 12 and can start to get an idea of storm tracks.

NSSL-WRF simulated GOES-R low- (top), mid- (center), and high-level (bottom) WV imagery for 0000 UTC on 24 May 2011.
As we continue through time past initiation, we can take a look at the three GOES-R WV channels produced from the NSSL-WRF imagery. Each channel peaks at a different level in the atmosphere, essentially providing us with 3 layers of water vapor measurements. Currently unavailable on our operational GOES satellite, this will be available with GOES-R and we can simulated it using numerical models. What is particularly interesting in this imagery at this forecast time is the presence of a very strong dry signature (red colors) extending from the TX panhandle into central OK in the high-level water vapor (bottom image above). This is an indication of very strong mid-level jet streak. This signature is present in the lower level WV images as well.

Simulated satellite imagery

The Convective Initiation group compared simulated ABI and current GOES water vapor imagery to examine the dry line over Texas and western Oklahoma and to evaluate the performance of the NSSL-WRF through early morning. The presence of lee waves downstream of the mountains in extreme southwest Texas was noted on the imagery. Overall, the NSSL-WRF accurately depicted most of the large-scale features, with the usual differences in the locations of individual cloud and convective features. The simulated imagery indicates that convective initiation will occur later in the day along the dry line from south-central Kansas to north Texas. The dry line was also evident in the mid-level (band 9) water vapor imagery prior to convective initiation.

-Jason Otkin

Monitoring CI over OK...

EWP NWS forecasters have begun real-time operations within the HWT. We are focusing on the UWCI, UAH CI, and Nearcast products over the domain waiting for convection to develop along a dryline extending from central OK down across the Red River. An area of cumulus clouds have begun to form along the dryline and we are waiting for further development. An area of thin cirrus (our worst enemy) is moving in rapidly from NM and will eventually impede upon our ability to detect CI from the satellite based products (see image below). We are hoping that CI will occur prior to the cirrus entering the area. Below is an example of what we are looking at, with the UWCI and ice cloud mask overlaid on visible satellite imagery. A false alarm has occurred due to the thin cirrus being misclassified by the cloud typing algorithm and created a false cooling event as it passed over land.


The EFP is also monitoring CI on the CI desk and have been looking at the Nearcast product extensively over the area. They have noticed that the Nearcast has been showing a band of moisture and increased instability potential aligning itself with the dryline and then being advected quickly east. They are concerned that if this area of moisture and instability moves too far east before CI occurs that the potential for any severe convection will be limited. I explained to them that the RUC winds may not be truly representative of what will really happen and to monitor the new forecast that came in at the top of the hour to see if this trend continues.

Simulated satellite display change

Forecasters and participants within the EFP severe and CI desks suggested to us a change in how we display the simulated satellite products from the NSSL-WRF within the NAWIPS systems. They use the simulated satellite not only to forecast, but also to compare the model output to observed satellite imagery. They noticed that the projection we were providing to them did not match the observed satellite data. They suggested to us that we make the projections more similar to the satellite data... so we did, and here is the before and after...

BEFORE
AFTER

Day 3 forecaster interactions...

This morning 3 of the visiting forecasters participated in the EFP's new CI desk. The discussion was based on where they expected new convection to occur within a selected domain encompassing most of OK, the northern half of TX, southern half of KS, and eastern halves of CO and NM. The simulated reflectivity from the NSSL-WRf was examined early during the forecast period to help determine the accuracy of the NSSL-WRF model. While it was decided that the NSSL-WRF didn't capture the early MCS over W. TX and OK, it did show some potential useful information regarding CI forming along the dryline later in the day once the MCS moves on and instability returns. We also examined the 10-12 micron band difference product to help determine specific areas where CI would occur (see below).

NSSL-WRF simulated GOES-R 10-12 micron band difference for 1900 UTC on 11 May, 2011. Arrows indicate areas where low-level moisture is favorable for convective development.
While the group decided collectively on a conditional slight/moderate/high contoured area, individual participants were asked to select a point where they expect the first CI to occur within 25 miles, as well as what time they expect it to occur and their confidence in their forecast. This input helps generate a human based PDF that can be compared to the model generated PDF following the forecast period. I picked a point near Lawton, OK at 2000 UTC with a 30 min +/- window and a 70% confidence... we'll see how I do.

NSSL Scientist Mike Coniglio leading the forecast discussion at the EFP CI desk.
Following the CI desk forecast, invited EWP forecasters began working on an initial AFD on their AWIPS stations. Forecasters are using a combination of operational model field, as well as some experimental data from the Nearcast and the OUN-WRF. Ralph Petersen spent some time with the forecasters to explain how the Nearcast output could help increase their confidence of thunderstorm development. Forecasters have seemed very interested in a strictly observation-based forecast out to 9 hours... some have even asked how to get this data back into their AWIPS at their local WFO.
Ralph Petersen of UW-CIMSS explains the Nearcast product to NWS forecasters during real-time forecast operations.

UW-Madison CIMSS convective initiation, overshooting-top, and nearcasting update

GOES-R proxy University of Wisconsin convective initiation (UWCI), overshooting-top/enhanced-V, WRF ARW simulated data and nearcasting fields have been flowing in a smooth manner into the EFP via N-AWIPS for forecast discussion integration. UWCI did indicated individual cells developing along north-south boundary in MN yesterday afternoon (10 May 2011).

24-hour UWCI indications, overshooting-tops, and NLDN lightning data from 12 UTC 20110510 - 12 UTC 20110511 below:



Example GOES Sounder nearcasting product within N-AWIPS with radar overlay on top. Red and yellow areas indicate regions of conditional instability.



The usual first week hiccups in GOES-R HWT experiment. Unfortunately the UWCI and Overshooting-top/thermal couplet products are strangely flipped from north to south during GRIB2 to AWIPS netcdf decode at HWT. Jordan Gerth is talking to local AWIPS expertise to resolve the issue however no solution so far. This is preventing evaluation of products within EWP. Nearcasting and WRF simulated data are available.

Day 2... Data Flow

So today marks the first full day of the experiment... The morning started with a few data flow issues... all of which have been resolved. The data flow for the Spring Experiment is now completely up and running...

The morning EWP forecasters have been sitting with the EFP CI desk where they have been looking at the NSSL-WRF simulated satellite imagery as well as the 10-12 micron band difference while deciding what domain they should choose for their forecast.

The EWP morning shift have written their first area forecast discussion (AFD) for where the EWP should operate throughout the afternoon... which they have chosen to be central TX. The EFP will continue to discuss their forecasts until lunch and then we will have our first joint EFP/EWP map discussion at 1pm.

Will update as the day progresses...

Let the 2011 Experiment Begin!

Welcome back! It's that time of year again, when we all get together for a 5-week period and talk about science!

We are officially less than 1 week away from the beginning of the experiment so I thought I would get on, knock the dust of this thing and update some of the links. Once again, participants will be encouraged to also post on this blog about their experiences at the experiment and with the products being demonstrated this year.

This year's experiment will be slightly different than previous years with the addition of a morning shift within Experimental Warning Program (EWP). Also, the Experimental Forecast Program (EFP) has added a dedicated convective initiation (CI) desk that will work closely with the EWP morning shift and GOES-R to make forecasts of convective initiation throughout the day. The EWP will also continue its traditional warning shift and the EFP will continue to operate its severe and QPF forecast desks. We are hoping to have more cross participation between the 2 programs this year starting with the EWP morning shift/EFP CI desk collaboration, as well as a new daily 1pm joint briefing.

We will be having 9 individual products being demonstrated this year... some updated versions of previous products and some completely new ones. Below is a list of what we will have this year...

- SATCAST convective initiation nowcast (UAH/SPoRT)
- UWCI / cloud-top cooling rate (UW-CIMSS)
- Overshooting-top / thermal couplet detection and magnitude (UW-CIMSS)
- Psudeo-geostationary lightning mapper (NASA SPoRT / NSSL)
- 0-9 hour Nearcast (University of Wisconsin - CIMSS)
- 0-3 hour severe and significant hail probability (CIRA)
- NSSL-WRF simulated lightning threat (NSSL/USRA)
- NSSL-WRF simulated satellite imagery (UW-CIMSS/CIRA/NSSL)
- NSSL-WRF simulated band differences (CIRA)

The details about these products will begin to emerge as the experiment unfolds and we will be providing real-time posts of product cases and interactions with forecasters during experimental forecast/warning operations.

I look forward to working with all of this year's participants and expect a very fruitful experiment. I would also like to thank everyone who has helped put this together so far, as well as those who have agreed to participate.

End of the experiment

Well, this marks a close to this year's Spring Experiment activities. We will begin again in the late summer this year with the Fire Weather and Heavy rain experiment starting August 24 and ending September 3. I would like to thank all of the participants this year from the various cooperative institutes and partners for coming and assisting in the product training and participating in the experiments alongside the forecasters. Without this participation, the experiment would not have been a success. I would also like to thank all the forecasters who participated this year and took valuable time away from their WFOs to come out and give us their time. The feedback gathered from the forecasters in the EFP and the EWP this year provided invaluable information to help improve the GOES-R products we evaluated this year. While not all feedback gathered this year may have been positive, it is important to remember that understanding the shortcomings in the demonstration strategy and the products themselves is essential to develop a robust product set prior to operational use once GOES-R launches. I would particularly like to thank Andy Dean, Gregg Grosshans, Israel Jirak and Chris Melick from the SPC's Science Support Branch for setting up and providing technical support for the NAWIPS systems on the EFP side. I would also like to thank Ben Baranowski and Darrel Kingfield from WDTB, as well as Kristin Kuhlman, Kevin Manross, Greg Stumpf and Travis Smith from NSSL for their assistance in setting up the AWIPS systems and providing technical support for the EWP side throughout the weeks. Without all of these people there would have been no experiment and I greatly appreciate all of their efforts. We are looking forward to continued interactions with the forecaster and product developer communities throughout the next year and into the coming years.

Thank you!