Category: PHSnMWnABI

Albuquerque HWT

Posted in NUCAPS, OCTANE Speed Sandwich, PHSnMWnABI, SPG2023 on by Kevin Thiel.

Storms are exhibiting some decent shearing aloft over NW New Mexico when comparing to NE New Mexico. Something I might not have noticed had I not had this product as I don’t always have time to go into the SPC mesoanalysis and check various levels of shear values. The 0-8km shear values are in the 40-50 kt range, in agreement with the range of values noted on the speed shear values of OCTANE. See below.

PHS really doing a nice job of pointing out peak areas of MUCAPE and where storms will likely develop. Decent scale and resolution results in some good quality comparisons with various other products. This is over the southern ABQ CWA.

Forecast Layer Comp Refl 21Z

Forecast MUCAPE 21Z

Forecast MUCAPE 23Z – Also, noting a sharp gradient in MUCAPE values as convection strengthens over east-central New Mexico late this afternoon into the early evening hours. We will have to see how this plays out.

MUCAPE values seem a bit higher than they should be when compared with the MLCAPE values at the same times over New Mexico. I’m not exactly sure why the values are so high, but the forecast RAP values for the same time frame appear to be notably more displaced to the east and lower.

Example below from forecasted time 02Z.

The 6 hour forecast at 21z of PHS 0-6 km Bulk Shear (first image) is compared against the 21z SPC Mesoanalysis (second image). Overall, the PHS forecast did quite well over New Mexico. There is generally little to no shear across the state except for near the Four Corners in the northwest and far southeastern New Mexico. The values are reasonable in these areas as well, around 16 m/s for PHS which fits in with the over 30 knot SPC values.These differences can be noted in the convection occurring as well (seen in the SPC image). Mainly isolated cellular over central NM, but showing more organization in the areas of higher shear.

-Satellite Steve and Burton Guster

 

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Monitoring South FL Convection for the Miami Open

Posted in DSS, LightningCast, NUCAPS, OCTANE Speed Sandwich, PHSnMWnABI, ProbSevere, SPG2023 on by Kevin Thiel.

We’re closely monitoring for CI near the Miami Open Tennis Tournament (location noted by the Home marker). Thus far this afternoon, the deepest convection has been in the west, NE of Naples, where the Band 13 imagery shows high cloud tops with cool brightness temps (-66C), and Octane imagery shows a good divergent signal.

So far, LightningCast has focused on the convection in the western peninsula, with the maximum slowly translating inland and to the N along the inland-tracking sea breeze.

This is further confirmed by the lightning meteogram for the DSS site. Looks like they can keep playing tennis for a little bit longer!

Looking at the storm clusters back west, a NUCAPS sounding near that cell shows plenty of CAPE.

The NUCAPS-Forecast MUCAPE confirms the high CAPE invof the storms.

Let’s see what the forecast shows for our DSS event. By 02z this evening, it shows increasing CAPE invof the DSS event. They are not out of the woods yet!

However, ProbSvr3 and LightningCast continue to provide a general idea that the strongest cell remains north and west of the Miami Open, limiting any impacts during the event.

Looking at the PHS imagery, it shows continued moderate CAPE extending into SW FL invof the ongoing convection, with much lower CAPE near our DSS event.

And the projections for 00z this evening show CAPE lowering further.

20z PHS Composite Reflectivity compared to MRMS Composite Reflectivity persistently highlights a lot of noise. Understanding from a forecaster’s perspective, this can be mentally filtered out, but at the same time, remains to be a distraction from the overall product’s use.

The warned cell over Glades county weakened and merged with other convection, and accordingly, the LightningCast probs declined. But we’re seeing new vigorous convection to the WSW just north of Bonita Springs.

One interesting note. There are new cells developing in far SW FL with lightning noted on GLM, however the cirrus canopy there is too thick to allow LightningCast to detect this convection.

– Edgar and Harvey Specter

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Severe Cell in TFX CWA

Posted in OCTANE Speed Sandwich, PHSnMWnABI, ProbSevere, SPG2023 on by Kevin Thiel.

At WFO Great Falls (TFX), we made use of the Octane speed and direction imagery, plus the IR brightness and day-cloud phase distinction to evaluate a cell northeast of Iliad. This imagery helped us screen the multiple cells over the CWA so we could home in on this particular cell. Characteristics that stood out included the higher anvil speeds on this cell, the diffluent cloud top signal on the Octane direction imagery; the cooler cloud tops (around -62C), and new/robust convection noted by DCPD.

4 Panel OCTANE depiction of severe warned storm near Iliad, MT.

Meanwhile, the cell closer to the Canadian border is becoming stronger. The ProbSevereV3 is trending higher for total severe, up to 19% at 2104Z. The anvil from the storm to the south is beginning to impinge on the cell to the north and somewhat obstruct the view.

The PHS imagery showed a regional peak in MUCAPE in this area.

Looking a bit later, the total ProbSevere continues to climb. It is well above the individual probabilities, which is curious.

Storms have matured with a notable V notch of cooler cloud tops and warmer tops to the north of the notch. Based on Octane speed, there is a notable difference in speeds from the southern end of the anvil to the northern reaches with 35-40 kts increasing to 65-70 kts. PSv3 does indicate a 50% chance for severe with this storm.

Meanwhile, down in CA, northeast of Sacramento, the Octane direction product is showing an impressive divergence signal!

–  Satellite Steve and Edgar

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BRO PHS COMPdBZ comparison

Posted in PHSnMWnABI, SPG2023 on by Kevin Thiel.

Here is a comparison of the 15z  PHS Composite Forecast at 21z to the 21z MRMS Composite Reflectivity. Notice that the PHS has more widespread convection than what actually occurred. However, the PHS did forecast the translation really well (not shown here), which would aid forecasters in understanding where current convection is likely to travel.

21z MRMS Composite Reflectivity

15z PHS Composite Forecast for 21z

– Burton Guster, StormofCentury, Harvey Specter

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PHS 0-3km SRH for WY/MT – 5/25/23

Posted in PHSnMWnABI, SPG2023 on by Kevin Thiel.

PHS 0-3km SRH for WY/MT – 5/25/23

Shear parameters are highlighted for the afternoon time period across Northern WY and far Southern MT (northwestern portions of the image domain). Radar observations later on indicated this product did well, with several cyclic supercells moving NE to ENE across far Northern WY, and entering into Southern MT at the writing of this post. This product demonstrated higher resolution, though similar placement of convective elements from the same product on the HRRR model.

 

PHS 0-3km SRH – 20Z – 5/25/23

PHS 0-3km SRH – 21Z – 5/25/23

PHS 0-3km SRH – 22Z – 5/25/23

PHS 0-3km SRH – 23Z – 5/25/23

– Rain-Free Bass Guitar

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Growing Lightning Threat in Carter County, MT

Posted in LightningCast, PHSnMWnABI, SPG2023 on by Kevin Thiel.

Growing Lightning Threat in Carter County, MT

LightningCast probabilities steadily increase across Carter County, MT (Far SE MT) through the late afternoon. Perhaps the user could opt to select a more detailed range of probs by using the density radio button option in the product menu. At the moment only the 10/25/50/75% probs are available.

Probailities for lightning are steadily increasing over Carter County as convection forms along the cumulus field observed running SSW to NNE across the county. 

Surface-based CAPE from the PHS product indicate values increasing to 2,000+ J/KG across far SE MT.

– Rain-Free Bass Guitar

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Evolution of LightningCast Over Southern Montana/DSS Event In Billings

Posted in DSS, LightningCast, PHSnMWnABI, SPG2023 on by Kevin Thiel.

Upper level flow shows continued SSW flow aloft over the region, thanks to deep troughing remaining over the West Coast. Overall forcing through the afternoon is on the weaker side of things, but models show an upper level jet streak nosing into the area. Scattered thunderstorm activity has already developed (below) to the south of Billings in northern WY, and is expected to expand in coverage through the afternoon. The DSS event is noted by the large yellow “B” over Billings.

The 14Z PHS forecast output (below) showed 19Z MUCAPE values across the area ranging roughly from 1000-2500 j/kg (with highest values in the eastern areas). Looking further into the mid-afternoon hours, outside of MUCAPE values creeping closer to 3000 j/kg in far NE portions of the CWA, the PHS overall didn’t show any notable changes in values. PHS values of 0-6km shear also matched up fairly well with SPC Mesoanalysis at 19Z, and had values increasing to around 35-40 kts through the afternoon.

Below is the 19Z MUCAPE via the SPC Mesoanalysis page.

LightningCast right around 19Z showed the 10% probability contour still about 40 miles SSW of Billings at its closest point (below).

LightningCast right around 20Z showed the 10% probability contour still about 30-35 miles W-SW of Billings at its closest point (below).

Around 2045Z, the 10% prob. contour reached the DSS event(below), but overall activity continues to be slow to push NNE. The LightningCast Time Series is included to show the trend up to this point.

Fast forward to roughly an hour later (~2140Z), there’s been a bit of a jump in the LightningCast Probability/TimeSeries (below), with the DSS event now sitting with a roughly 35% probability of lightning in the next hour.

A few minutes later, another jump up in probability – up to around 50%. Below is an image that has the GLM FED (colored pixels) included with the radar, LightningCast, and ENI Total Lighting Plot.

You likely have already been talking with the DSS contact point, but this jump up in the last ~10 mins may warrant another update, conveying that there is an increasing probability of lightning occurring in the next 60 mins.

Not surprisingly, the LightningCast probabilities have continued to increase, also shown in the time series. Image is from 2220Z.

What’s the best way to pass along this information to the DSS contact point?

With this type of event, where it’s slow to move in (driven more by the upper forcing vs the somewhat random quicker-developing activity that can occur in high CAPE/low shear  and other types of environments) and no significant changes in the overall environment across the area, perhaps you could wait until it’s closer to 50% or more  before expressing greater concern for the threat of lightning.  In those instances where activity may be quicker to develop/strengthen, it’s not out of the question that values closer to the 25% contour would warrant greater concern. No matter the overall environment, I do believe the addition of a shorter-term probability (lightning within 30 mins)  would be beneficial.

– Bubbles

 

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PHS and GLM Data for Tampa Florida this Afternoon and Evening

Posted in GLM, News, NUCAPS, OCTANE Speed Sandwich, PHSnMWnABI, ProbSevere, SPG2023 on by Kevin Thiel.

General Risk for Thunderstorms in Florida this Afternoon and Evening

The Tampa CWA is in a general risk for thunderstorms this afternoon and evening per the SPC.

The main potential impacts are frequent lightning, heavy rainfall, and gusty winds thanks to decent amounts of SBCAPE.  Localized flooding  also remains possible, especially in urban areas,  due to slow storm motion as PHS shows no 0-6 km Bulk Shear over Florida. This matches well with the latest SPC Mesoanalysis which also shows no 0-6 km Bulk Shear shear over the region.

NUCAPS showing SBCAPE values at 21Z. Values are highest across the central and southern portions of the Tampa CWA. Areas in green had values around 1600-1700 J/kg. Areas in teal show values ranging from 800-1400 J/kg. Areas in purple range from 200-300 J/kg.  PHS shows a similar trend to NUCAPs with higher areas of SBCAPE across the central and southern CWA with lower values across the northern half of the CWA. However, the color scale on the online version of PHS is difficult to interpret as the gradient ramps up from light red to dark red. So, you cannot really pinpoint specific values of SBCAPE. However, you are able to see areas of lower SBCAPE and areas of higher SBCAPE at a glance. 

ProbSevere version 3 increases our confidence that storms will remain generally sub-severe as ProbSevere values are below 10% across the Tampa CWA as of 1930Z.The Octane Speed Sandwich product further confirms that storms are remaining below severe limits as the strongest storms are noted over southeastern Florida this afternoon as of 1930Z. Not only do these products help us pinpoint areas of potential severe weather, but they also help us pinpoint areas of sub-severe weather.  GLM shows lightning activity increasing across the Tampa CWA early this afternoon, and activity is expected to gradually increase in coverage as more thunderstorms develop through the late afternoon and early evening hours.  Lightning Cast around 1930Z shows lightning probabilities increasing across the Tampa CWA over the next hour. Pink contours represent a 75% chance of lightning in the next hour. Green represents a 50% chance, teal a 20% chance, and dark blue a10% chance of lightning in the next hour. GLM showing lightning activity increasing across Florida from 1930Z through 2016Z across the Tampa CWA. Areas showing more oranges and yellows have shorter flashes and more lightning density. These areas help us know where stronger updrafts are located. The strongest updrafts at the time of this loop remain outside of the Tampa CWA.  -Dwight Schrute

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Satellite HWT Day 3 Carl

Posted in GLM, LightningCast, News, OCTANE Speed Sandwich, PHSnMWnABI, SPG2023 on by Kevin Thiel.

Wednesday Satellite HWT Thoughts

PHS Model Comparisons and Thoughts

Above: Top is HRRR SHIP parameter, bottom is PHS SHIP parameter.

Looking at some of the convective parameters and indices around the CWA I was working with today (PUB), one thing that really stood out to me was how “splotchy” many of the parameters were when compared with the HRRR model. It’s very hard to believe that the model, especially at a 3 km resolution, is able to obtain that level of accuracy with regards to these parameters, or at the very least having gradients this sharp in many of these parameters doesn’t make much sense. Wondering if some of it is being driven by the extreme CAPE gradients that do show up later on, which are certainly going to be drivers in many of the severe indices.

Another thing I noticed is what looks to be a wave-like numerical instability within the first hour of the model – this could be having some big impacts on the model forecast, as you can see these reflected in the base fields (T, u, v, etc) and then having impacts on many of the other derived parameters that last through the forecast period, as shown in the image below:

CAPE also seems to initialize really high, then “jump” down to a lower value at the first hour. This is quite a large “adjustment” from the initial conditions that the model seems to start with. Shown below are hour 0 of the 14Z run and hour 1 of the 14Z run from Wednesday 5/24.

You can also see the numerical instability within this field that is in place across a large portion of the domain.

OCTANE

Octane was able to capture an interesting view of the Above Anvil Cirrus Plume on a very powerful storm along the New Mexico/Colorado border during the afternoon hours. The cirrus is a bit slower than the surrounding clouds within the sheared environment, providing that “V” type shape that we’ve come to associate with some of the strongest updrafts:

Another good example of using Octane for surveillance of storms – the direction product really highlighted another storm that quickly grew on the flank of another severe warned storm. Big value especially in areas where radar coverage might be limited by mountains, such as in the CWA I was working in today (PUB):

LightningCast

Used the LightningCast product extensively for DSS purposes today. We had a pretend outdoor event located in Pueblo, Colorado. A very strong thunderstorm (MESH estimated nearly 3″ or larger hail at one point) which passed within a few miles to the south and east of the city. I used the LightningCast probabilities in AWIPS overlaid with satellite data to provide multiple updates to Emergency Management, using it to confidently state that probabilities of lightning were increasing as storms approached from the south. Lead time for action would have been within the 45 min to 1 hour range. Was able to confidently say they would see lightning within the 10 mile range a good 15-30 minutes before the first strike occurred within the range per the ENTLN network data. Below is the LightningCast time series as output on the webpage for the KPUB airport, which is very close to where the DSS event was taking place:

There is definitely some very actionable lead time here. As a forecaster, having this type of data available to me outside of AWIPS is a game changer. I know it may be challenging, but being able to click on a point like this and get this type of information would be huge for briefings and emails with decision makers. Right now we are limited to airports. Even a relatively coarse mesh that would allow me to pick a close point would be extremely useful if these images can’t be generated on the fly. Other possible ideas include only generating points within a certain LightningCast threshold (say 10%), or generating them on the fly based on a click query. That all said, even in its current form I will be using it going forward, and making a point to share it with my office and WCM for DSS.

I also made a social media type graphic using the LightningCast product for hikers, given the large number of mountains within the CWA. Perhaps would have been a bit more meaningful to have sent this as storms were beginning to form, but they were already cooking once we got spun up and started. Highest probabilities were hugging the mountains where storms were forming. If I were formally posting to social media, I may have added some lightning safety graphics or something to that effect as part of the post (twitter thread, multiple images in Facebook post).

GLM RGB

This product does a great job in my opinion combining information from the FED and MFA. I found it useful for detecting lightning jumps within storms while still maintaining information about the overall coverage of lighting. Would happily use this as my primary GLM viewing option in AWIPS.

-Carl Coriolis

 

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Afternoon High Plains Convection in Southern Colorado

Posted in HWT, News, OCTANE Speed Sandwich, PHSnMWnABI, ProbSevere, SPG2023 on by Kevin Thiel.

Today we focused on the Pueblo, Colorado  CWA for afternoon High Plains convection. Scattered convection developed across the CWA leading to large hail and damaging winds. The first Severe Thunderstorm formed on our CWA border with Albuquerque and drifting south into their CWA. A second Severe storm developed and tracked north towards our DSS Event in Pueblo, bringing the potential for large damaging hail and strong winds.

15Z PHS MUCAPE valid at 18Z showed around 2000  to 2500 J/kg for green areas while areas in blue had roughly 1000 to 2000 J/kg.
SPC MUCAPE Mesoanalysis valid at 18Z shows similar trends to the 15Z PHS MUCAPE values.

16Z PHS valid at 21Z showed a slight upward trend of MUCAPE in the eastern half of the CWA. 

21Z SPC Mesoanalysis showed increasing values of MUCAPE developing just south-southeast of the CWA, similar to the 16Z run of the PHS shown above. 

 

15Z PHS STP valid at 18Z showing little overall threat for tornado concerns through early afternoon, for the most part values were less than 0.25. 

SPC Mesoanalysis page showing 18Z STP values similar to the 15Z PHS forecast. 

The image below shows the Octane Speed product on the left and the Octane Direction product on the right, focusing on a cluster of activity near the Jefferson/Douglas County line in Colorado. Picked this screen capture as it showed a wide range in values, mainly for the Direction product. The Octane Speed product shows some speed shear present with the lighter speeds (darker blue, ~5 kts) transitioning to brighter green/a bit of yellow (~30 kts). The magnitude of directional shear was higher, showing direction of motion/divergence ranging from ~170 degrees (core of red area) to ~295 degrees (core of green area).
Below is a animated graphic showing the transition in both products. 

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Chose to grab this Octane Direction product screen capture as it shows an elongated area of storm top divergence through central Colorado.  The red/magenta colors show direction generally from the 170-190 degree range, while the green/yellow colors show values from the 275-285 degree range. The black areas are spots of data dropout, which can occur when the speed shear product drops below 5kts.

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First Severe Thunderstorm Warning issued for this area today came right after 20Z, based on ProbSevere values/time series as well as the Octane Speed Sandwich product.  Probabilities ramped up quickly for both ProbSevere and ProbHail on this storm at the edge of the PUB/ABQ CWA boundary. Octane around “peak” of the storm.Low Level SRM and ProbSvr (0.5 deg slice is about 10.8k ft AGL)Mesh showing 3 inch hail on the border of the Pueblo CWA.

ProbSevere and ProbHail maxed out at roughly 90% while the storm remained severe. This storm eventually moved into ABQ’s CWA.———————————————————-

2nd Severe Thunderstorm Warning – Huerfano County

ProbSevere values and time series for 2nd Severe Thunderstorm Warning of the day, readout is at its “peak”…around 2045Z.
Octane Speed/Direction at “Peak” of the storm,  around 2045Z. Directional shear varied from ~205 degrees (reds) to ~285 degrees (greens).
ProbSevere showing the weakening trend of the storm gave us confidence that the storm was in fact weakening.  Octane speed/direction further confirming the weakening trend as colors become more diffuse in nature.

ProbSevere showing continued weakening trend. We decided not to issue another severe thunderstorm warning on this storm based on the trend.

Though this storm showed a weakening trend, it was a short-lived trend, as it still had ~2000 j/kg of MUCAPE and effective shear around 30kts to work with as it tracked farther north.

The storm ended up re-intensifying, as shown by the ProbSevere output/time series below. We went ahead and issued another Severe Thunderstorm Warning for very large hail.  An increase in both storm top speed/directional shear was also shown by the Octane product.The level reflectivity images show an impressive core peaking in the 36-40k ft range, shown in the 12.5 deg. slice. MESH showing nearly 4 inch hail south of our DSS event in Pueblo. The event was notified about the potential for large damaging hail.

 

-Dwight Schrute/Bubbles

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