Aug 9, 2012 CTC & Radar Comparison

Given active weather pattern (deepening upper level trough over Great Lakes) with showers and storms over Wisconsin, it wasn't hard to find quick growing cells with at least moderate Cloud Top Cooling (CTC) rates.

There were some breaks in the cloud field over northwestern Wisconsin.  Perhaps this helped oen cell in a line to pulse up.  We were able to spot CTC rates in the moderate range with a value of 17 to 18 over northwestern Washburn County.  Further north in St. Louis County of northeastern Minnesota we observed a CTC value of 12 to 13. See Figure 1 below.

Figure 1. Maximum CTC rates of 17 to 18 over Washburn County.

 We then compared the cells with decent CTC rates with what the WSR-88D Radars depicted.  SEe Figure 2 below for the radar image which corresponds to Figure 1.

Figure 2. Radar image at 1643Z August 9, 2012.

The decent CTC rates would imply an increase in cell intensity observed on radar.  This intensity increase is noted in Figure 3 below, especially in the St. Louis cell which had a 60 dBZ signature.  Of course, these storms were not severe, but it was nice to see that the CTC rate idea enabled us to anticipate an increase in cell intensity.

Figure 3. Radar image at 1706z August 9, 2012.

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

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

Moonlit Overshooting Tops in NPP VIIRS Day/Night Band

A strong cluster of thunderstorms developed over Central Michigan overnight on 3 July 2012.  These thunderstorms were captured by the Suomi NPP satellite overpass at 07:42 UTC by the Direct Broadcast antenna located at the University of Wisconsin-Madison Cooperative Institute for Meteorological Satellite Studies (CIMSS).  The data was processed and sent in real-time to the NWS office at Sullivan (MKX) where it was displayed in AWIPS.  The VIIRS Day/Night band provides forecasters with visible imagery at night at high spatial resolution (1km) from lunar illumination.  The first image below shows the features of the cloud tops, including overshooting tops as well as gravity waves.  Also visible are the lights emanating from the underlying cities including Detroit (large bright lights in the Southeast Corner).  The infrared 11 micron window brightness temperature image (second image) provides a thermal view of the same scene.  The coldest tops are -70C.      

Suomi NPP VIIRS Day/Night Band image of a strong thunderstorm over Central Michigan illuminated by moonlight with overshooting tops and gravity waves evident.  The Day/Night band supplies forecasters with a visible band capability at night when the moon is out.  The VIIRS data is acquired from the direct broadcast antenna at the University of Wisconsin-Madison CIMSS, processed via CSPP software and supplied to the NWS MKE office in real-time for display in AWIPS.  The image is from 3 July 2012, 07:42 UTC.

Suomi NPP VIIRS Window Channel Infrared image (11 micron) of a strong thunderstorm over Central Michigan.  The coldest cloud tops are -70 C, and the spatial resolution is about 1 km.  The VIIRS data is acquired from the direct broadcast antenna at the University of Wisconsin-Madison CIMSS, processed via CSPP software and supplied to the NWS MKE office in real-time for display in AWIPS.  The image is from 3 July 2012, 07:42 UTC.

Kathleen Strabala CIMSS, Steve Hentz MKX

GOES-R Fog/Low Cloud product over Lake Superior

The GOES-R Fog/Low Cloud product IFR Probability (that is, the probability of visibilities at or below 3 miles), below, shows a pocket of higher values near the coast of Lake Superior in northwest Ontario.  Visible imagery (bottom) confirms the presence of stratiform clouds in this region.  Southwest winds move relatively warm and moist air over the cooler lake surface (Lake SSTs are at or below 50), chilling the air to its dewpoint.   The GOES-R Fog/Low Cloud product fuses Rapid Refresh data and satellite data.

Scott Lindstrom, UW-CIMSS and Steve Hentz NWS-MKX

UW Cloud Top Cooling product and Lightning

The UW Cloud Top Cooling (CTC) product is used at NWS-Sullivan to anticipate (or corroborate) the development of deep moist convection and lightning.  Images above, of cloud-top cooling from Tuesday morning, 3 July 2012, show regions of cooling that occur just before (or concurrent with) the initial lightning strokes.  During the GOES-R era, when temporal resolution is increased, the ability of CTC to anticipate convective development should increase.

Scott Lindstrom, UW-CIMSS and Steve Hentz NWS-MKX

Ice Detection in Hudson Bay using VIIRS data from Suomi NPP

 VIIRS visible imagery (0.68 micrometers) (above) over Hudson Bay, 1801 UTC on 2 July.

VIIRS Snow/Ice Band (1.62 micrometers) (above) over Hudson Bay, 1801 UTC on 2 July

Channels on the VIIRS instrument on board Suomi NPP allow easy discrimination between ice and water clouds.  Ice is a very effective absorber of energy at 1.61 micrometers;  thus, if you compare visible imagery (top) with 1.61-micrometer imagery, regions that are very white in the visible (lots of reflection) and very dark at 1.61 micrometers (lots of absorption, not so much reflection) are assumed to be ice, either at the surface, or in clouds.  In the example above, ice is indicated over central Hudson Bay -- it is very white in the visible, and dark in the 1.61 micrometers.  Similarly, ice clouds are indicated over the southwest part of the image, where clouds are indicated as white in the visible, but not white at all in the 1.61 micrometers.  This is a handy method especially in winter to discriminate between surface snow and water-based clouds.

Scott Lindstrom, UW-CIMSS, Steve Hentz, NWS-MKX

Summer Local Area Testbed 6/19/2012

 This is the CIMSS Cloud Top Cooling image overlaid on the GOES regional scale visible satellite image displayed on AWIPS at 1902Z on June 19th, 2012. The display showed a -9.55C/15 min rate of cooling over Clay County, MN east of Fargo, N.D.

  
 This is the same image combination of visible satellite and CIMSS Cloud Top Cooling at 1915Z with a maximum cooling rate of -26.5C/15 min. over eastern Clay County, MN.

   This the GOES-R ABI Band 10 7.34um water vapor image valid at 18z 06/19/ 2012. Note the minimal highlight over far west-central Minnesota, with convection over northeast North Dakota and across northern Minnesota.

  This is the GOES-R ABI Band 10 7.34um image valid at 19Z 6/19/2012. Notice the pinpoint development of convection along the North Dakota/Minnesota border just northeast of Fargo.

  This is the GOES-R ABI Band 13 image valid at 20Z 6/19/2012. Note the rapid development near Fargo, as well as the more expansive development to the northeast.

 This is the IR image from 2001Z 6/12/2012. Comparing to the ABI Band 13 image above, note the similarity of placement of the cloud shield from the convection near Fargo as well as the cold cloud tops with convection to the northeast, though the actual IR image shows one continuous shield from the two areas, while ABI depicts two distinct areas. The ABI forecast was within one county of the actual development and had an excellent handle on the evolution of the convection in this time period. 

This is the 0.5 degree composite reflectivity image from the KABR WSR-88D at 1857Z 6/19/2012. The cell is developing over southwest Clay County, MN.

 This is the 0.5 degree composite reflectivity image from the KABR WSR-88D at 1902Z 6/19/2012. The cell continued to develop over south central Clay County, MN.The cell eventually strengthened as it lifted to the northeast with composite reflectivity of 55 to 60 dBZ over eastern Clay County at 1920z. The CIMSS Cloud Top Cooling product effectively tagged this cell 18 minutes before it reached peak intensity.

Bob McMahon NWS MIlwaukee/Sullivan WI

End of the 2012 Spring Experiment

This marks the end of this year's Spring Experiment in the HWT.  We had a very productive 6 weeks of experiment with 32 NWS forecasters invited to participate in activities this year.  I would like to thank all of those visiting scientists who came and participated with the forecasters during this year's activities.  Without the help of the visiting scientists, it would have been difficult to capture all of the quality feedback that we did for the various GOES-R Proving Ground products.  In addition, I would like to thank the local NSSL/SPC/NWS personnel that kept this thing running week-to-week.  I would like to give special thank you to Darrel Kingfield at NSSL for putting together this year's Weather Event Simulator case for training and making AWIPS II ready for prime-time in the HWT.  Finally, I would like to thank WDTB for organizing and running this year's weekly "Tales from the Testbed" webinars.  They were a great success, giving the forecasters the opportunity to champion the products they found most useful to their peers across the country.

We already have a lot of exciting ideas to move forward over the next year in the HWT.  In addition, I am sure there is still plenty of exciting weather to happen this year.  I will be posting some examples of how the GOES-R Proving Ground products available to the Storm Prediction Center perform during these cases when possible.  Stay tuned!

Final EWP weekly debrief

Today marks our final day in the Spring Experiment!  We spent a couple hours prior to the weekly "Tales from the Testbed" webinar debriefing our final group of forecasters on their experience this week with the various products and the experiment overall.

SATCAST / UW Cloud-top Cooling
- "I'm going to go back to work and be asking my ITO during operations, 'where's the CTC product?'"
- "I thought both the CI products were very useful... the CI product (SATCAST), I like the idea of having the probabilities... I not sure that you really need the low ones (maybe under 50)... you weren't seeing CI with those values...  There were some times where we would see some organization with some areas with low values and I started to think that something would happen, but nothing did... so I wonder if it might be misleading."
- "I think there is definitely benefit in forecasters having access to both of the CI products... I found myself comparing the two to each other a lot and gaining my confidence that something was really going on."
- "I wasn't sure how much usefulness there was over elevation (for both products)... which could be expected... you really need to be aware of your environment."
- "If you looked at the day where there were the Dallas supercells, I found it really useful... I actually warned on the CTC and it worked out well... It preceed the 60 dBZ and 1" mesh by about 20-30 minutes."
- "I tended almost to gravitate more to the CTC... the CI product had more false alarms, maybe not with the highest probabilities, but there were a lot of 70s that did nothing."
- "There was a lot of noise with the lower values in the CI product... I can easily go in and turn of anything below 50 in the color curve if I wanted to."
- "I had several cases where I would get a 70-75 on the CI and then there would be nothing on the CTC, and then 15 minutes later there would be something on the CTC and that usually resulted with 50 minutes or so of lead time."
- "I did find some blue areas with lower values... I'd rather see that than have nothing there."
- "A yes/no value is not the answer for something like this."
- "It would be nice to see a trend of if your CI forecast is increasing... some space and time averaging might be helpful."
- "I can see these being even more useful in RSO."
- "I was really pleased how the CTC product picked up on the bigger storms...  I'd be curious to know how this would do over some of the more mediocre stuff."
- "The lead times with repect to the cooling rates seemed to correlate well to what we saw in the training material... there was one where we had 70 minutes lead time on severe."
- "We had one cell that had about an hour and a half lead time of severe from the CTC."
- "We had one cell that already had ongoing hail and then we saw an additional spike of CTC and there was additional development that eventually lead to a tornado... that was interesting to see."
- "Yesterday in Hastings we had a -34 C / 15 mins signal early on... there were some weaker storms ongoing at that time and it seemed like the stronger convection formed a little south of there afterwards... it definitely clued us in that something was going on."
- "An hour by hour verification over a one or several month period would be nice to see how these signals relate to things like trying to erode the cap."

Nearcast
- "The problem I had with this was the expansion of the 'black holes'... it came to be that after about 3 hours it became limited in usefulness... if there was some way to fill that in, I think it would be more useful."
- "It kept saying that there was an area of unstable airmass where you knew clearly the front had already moved through... forecasters need to keep an eye on the total picture."
- "I found it to be useful when I was in the HUN area... the instability kept showing up to the SE and I had some confidence that the storms would continue to maintain as they moved through the area."
- "On the boundary of the GOES-E and GOES-W domains, it would be nice to have some continuity from one product to the other." - It is anticipated that UW-CIMSS will do this in the future.
- "I wanted to see how the model based CAPE analysis compared to the Nearcast CAPE and they matched (at least in pattern) pretty well... I usually have to go to the web to get those analyses, so it would be nice to have something to compare to that.  Having a forecast component to it as well was nice to have."
- "I can get used to the colors as long as there is a sharp enough contrast and they are consistent."
- "That day we had those storms in N. Mexico... that mid-level theta-e showed a nice moisture axis where storms ended up developing."

Simulated Satellite
- "I wish I could have looked at it more... a lot of the days we already had stuff going on when we walked in."
- "I think it would be helpful in a forecast office to see what the NSSL-WRF did in an easily interpretable forecast.  It was pretty accurate on many occasions out to 30 hours.  In this week it was very good on the initialization of the convection."
- "If you're trying to do short term forecasting it might not be so great, but when you're trying to get the bigger picture it's really great."
- "Have you guys thought about any sort of average error for the location of the storms?" - No, but this might be possible with the push to include this in ensembles... like with the CAPS ensemble simulated satellite imagery we are demonstrating in the EFP.
- "Some sort of probabilistic field might be useful for cold cloud tops are would be useful." - Again, this might be possible with an ensemble method.
- "I would use this as a quick first look."
- "It would be nice to have a 12 UTC run in there."

RGB Airmass
- "The differences are very subtle... it might be a little tricky to use in a forecast office... it would take some using to get used to."
- "It would definitely be useful in a synoptic sense."

PGLM
- "The first day in HUN's area... the total lightning was useful... we started to see an increase in total lightning and we issued a warning... then we started to see the radar returns begin to get deeper and stronger."

Overall / Training
- "It was really untimely that we would lose satellite for 30 minutes to an hour at 1800 and 2100 UTC." - Partially a full-disk scan issue and a known AWIPS II issue not being able to match GOES-E and GOES-W timestamps properly.
- "This was my third time here and I thought that this year's orientation was really good... well organized... it let us get to work right as we got here."
- "The WES case was pretty slick, I wish I had another one... I loaded it on my laptop and it was very effective."
- "I would almost like to see an abbreviated DRT-type case in addition to the job sheet method."
- "Setting up the procedures on the first day was a little difficult... when I found the ones that were created before, those are the ones I started using the rest of the week."
- "It was good having an experienced person who's been here before there to help you through what you guys wanted from our evaluations."

ABQ: CTC + Situational Awareness = Great Fcst

Forecaster comments from EWP blog...

Although we are in AMA, we took a look at the CTC in NM, since that area has seen significant CTC signals over the last week. Once again, we are seeing strong CTC signals off the terrain in NM with little or no convective development. Here are a series of 3 signals in the same place over several hours. Take home point — this is a great product, however forecasters need to know their environment to use this product in enhanced warning ops and beware of times that the convection is being forced by the terrain. Case in point, although the CTC product showed -20->-25c/15min cooling values over higher terrain areas in SE NM, the sfc dwpts were in the teens and lower 20s. Almost no way convection could develop with this dry air.

2015z:

2215z:

2315z: