Tornadotod
Tuesday, May 3, 2016
Meso update for CAE CWA
1min SRSOS satellite imagery indicates destabilization underway eastward of surface cold front over NW SC. Subtle mid level SW trough ejecting eastward through the TN valley expected to initiate convection by mid afternoon over western portions of the CWA and further intensification east across the CWA. GOES LAP data (image below) shows well established and growing instability plume thus severe storms possible given adequate shear seen in GOES derived winds. Will continue to monitor...
Tornadotod
Tornadotod
Tuesday May 3 EWP operations begins at 11:30 am
Operations today began at 11:30 am. We remain on the East Coast, with groups operating in the Raleigh NC and Columbia SC CWA's.
Monday, May 2, 2016
Daily Summary: Week 3, Day 1 (2 May 2016)
Week 3 began with participants forecasting/warning for the Sterling and Blacksburg CWA's. The big story of the day was the severe weather experienced in the DC metro area, where storms produced large hail.
LAP
- Lap data showed the instability gradient well; that's where convection developed.
- CAPE was helpful in giving an estimate that storms were moving into a more unstable environment. Storms did develop along a strong CAPE gradient
CI
- I wish the color-table was labeled.
- The two areas in sterling that developed - regular CI capture it well with a couple hours of lead time
- Early in the day, there were probs just above 50% that did not initiate.
- Severe CI captured the development of the severe storm that hit DC
ProbSevere
- This is a great SA tool to have during warning operations. We have had it in the Milwaukee office for a few years now, and everyone uses it.
- I noticed that it did not do as well under the cirrus canopy where there was no satellite growth information
- When you see a jump in ProbSevere, you are alerted that the storm is strengthening.
- Especially on marginal days with a lot of subsevere wind and hail and trying to decide to warn or not, seeing a jump in ProbSevere gave me confidence to warn, and not seeing it also gave me confidence not to warn.
- Reverse trend helped. The storm went up, produced severe, then ProbSevere values dropped. At that point I knew I could let the storm go.
- We want to know which storms we need to look at now, and ProbSevere clearly shows this.
SRSOR
- It is a thing of beauty
- Especially for updraft growth, it is a great tool to guage how quickly the updraft is building.
A lot of time, radar is behind the curve
- It is neat to correlate satellite with radar, and see which cells in satellite correlate with cells in radar.
- The parallax error fix should be sent to all offices. With DC storm it was helpful in showing exactly where the storms were headed.
Sat-derived winds
- This is very good info. We watched a mid-level speed max approach our area, which increased environmental shear as storms developed.
Lightning Jump
- I don't like the display, I would prefer a contour
- I underlayed the jumps on radar, and it worked initially, but eventually got too difficult to see the product.
- It gave a good heads up to intensifying updrafts
- Seeing jumps with increasing ProbSevere indicated we better warn on this.
- Great SA tool
- With DC cell, we had a split, then a jump, helped me to rewarn on that storm
NUCAPS
- What I didn't like is how objective it is to adjust the temperature near the surface
- It will be beneficial to have the modifications automated, especially if used during warning ops.
- It did show there was a moisture increase and warming. This is nice to see in the soundings.
- Compared to the 18z RAOB, CAPE was right on, PW was a little dry.
LAP
- Lap data showed the instability gradient well; that's where convection developed.
- CAPE was helpful in giving an estimate that storms were moving into a more unstable environment. Storms did develop along a strong CAPE gradient
CI
- I wish the color-table was labeled.
- The two areas in sterling that developed - regular CI capture it well with a couple hours of lead time
- Early in the day, there were probs just above 50% that did not initiate.
- Severe CI captured the development of the severe storm that hit DC
ProbSevere
- This is a great SA tool to have during warning operations. We have had it in the Milwaukee office for a few years now, and everyone uses it.
- I noticed that it did not do as well under the cirrus canopy where there was no satellite growth information
- When you see a jump in ProbSevere, you are alerted that the storm is strengthening.
- Especially on marginal days with a lot of subsevere wind and hail and trying to decide to warn or not, seeing a jump in ProbSevere gave me confidence to warn, and not seeing it also gave me confidence not to warn.
- Reverse trend helped. The storm went up, produced severe, then ProbSevere values dropped. At that point I knew I could let the storm go.
- We want to know which storms we need to look at now, and ProbSevere clearly shows this.
SRSOR
- It is a thing of beauty
- Especially for updraft growth, it is a great tool to guage how quickly the updraft is building.
A lot of time, radar is behind the curve
- It is neat to correlate satellite with radar, and see which cells in satellite correlate with cells in radar.
- The parallax error fix should be sent to all offices. With DC storm it was helpful in showing exactly where the storms were headed.
Sat-derived winds
- This is very good info. We watched a mid-level speed max approach our area, which increased environmental shear as storms developed.
Lightning Jump
- I don't like the display, I would prefer a contour
- I underlayed the jumps on radar, and it worked initially, but eventually got too difficult to see the product.
- It gave a good heads up to intensifying updrafts
- Seeing jumps with increasing ProbSevere indicated we better warn on this.
- Great SA tool
- With DC cell, we had a split, then a jump, helped me to rewarn on that storm
NUCAPS
- What I didn't like is how objective it is to adjust the temperature near the surface
- It will be beneficial to have the modifications automated, especially if used during warning ops.
- It did show there was a moisture increase and warming. This is nice to see in the soundings.
- Compared to the 18z RAOB, CAPE was right on, PW was a little dry.
The Value of Prob Severe and the Lightning Jump Algorithm on Warning Operations
An impressive supercell took shape in Fauquier county, Virginia earlier this evening. This supercell tracked east towards D.C. then split around the city. The right mover maintained a large hail core and even had a large TBSS. The left mover took a sharp turn to the left and appeared to weaken but the ProbSevere prompted me to reissue a warning for the left moving cell. On the next radar scan, ProbSevere peaked back up as the cell strengthened. Both the left and right movers maintained strength and near 100% ProbSevere Probabilities for at least 1.5 more hours.
There was also significant lightning jumps shown by the GOES-R Lightning Jump Detection Algorithm. The max lightning jump was 8.0 Sigma near the time that the supercell split into right and left moving cells.
~Lilly Miller~
 | |
| Earlier in the storm evolution... (ProbSevere overlaid on top left panel with MRMS Composite Reflectivity, MRMS MESH on top right, MRMS Reflectivity at -20C on bottom left, MRMS Mid-level rotation track on bottom right) |
 |
| A little bit later... |
 |
| GOES-R Lightning Jump Detection Algorithm overlaid with KLWX Radar Reflectivity. |
Severe T-Storm Warning for Ashe County, NC
I was tracking a potential severe thunderstorm that was quickly developing just outside of the CWA in North Carolina.
I decided to put a warning on the cell because the Sigma for the lightning jump algorithm went to 1 (marginal) but the Prob. Severe jumped up to 82% very fast.
We have been checking with the NWS Chat window all afternoon and a trained spotter in Ashland in Ashe County reported quarter sized hail at 2250z. The warning I put out verified thanks to the heads up with the lightning jump detection and the Prob Severe Model.
-BW
We have been checking with the NWS Chat window all afternoon and a trained spotter in Ashland in Ashe County reported quarter sized hail at 2250z. The warning I put out verified thanks to the heads up with the lightning jump detection and the Prob Severe Model.
-BW
Overall Thoughts From Monday, May 2, 2016 - Prob Severe and Lightning Jump Helpful!
Overall, the Prob Severe model once again was a great asset for situational awareness for the storms for the Blacksburg, Virginia forecast area. It provided a heads up to the storms to watch for possible warnings. It was especially useful for when the Prob Severe values jumped quickly. This seemed to lead to an increase in reflectivity aloft via all tilts, and gave more confidence for issuing Severe Thunderstorm Warnings. The lightning jump product was also quite helpful with evaluating which storms to watch (similar to a jump in Prob Severe). This gave more confidence for issuing warnings with storms that showed the jumps in Prob Severe and lightning. JJW
End of Day 1
Lots of utility using GOES CI in tandem with GOES LAP to diagnose potential future convective hotspots. Once storms got going, prob severe model was excellent in delineating the strongest/highest severe potential storms. LWX warning operations were a great success!
Tornadotod
Tornadotod
Charlotte County, VA Severe Thunderstorm Warning - Prob Severe Helped!
I issued another Severe Thunderstorm Warning at 2254 UTC with the storm that was moving into Charlotte County, VA. The all tilts was not showing a lot of high reflectivity aloft. However, I issued the warning since the storm had a history of producing 1.00" hail and wind damage, and the Prob Severe model values were remaining in the 70s percent range. At 2254 UTC, the Prob Severe value jumped to 95%, which again gave me more confidence to issue the warning. Update: 1.00" hail in Charlotte County 2245 UTC and 2255 UTC. JJW
Parallax errors are huge!
Note the parallax error in GOES satellite imagery with the storm shown north of DC (yellow contour). Based on satellite alone one would believe the storm poses no threat, however radar data says otherwise as the storm is near the west side of DC...
Correcting for parallax error yields a much more representative collocation of satellite/radar observed storm location. This most useful fix should be ported to all A2 offices across the country.
Tornadotod
Correcting for parallax error yields a much more representative collocation of satellite/radar observed storm location. This most useful fix should be ported to all A2 offices across the country.
Tornadotod
7 Sigma Lightning Jump In Amherst County, VA
There was a 7 sigma lightning jump with the warned storm in Amherst County, VA at 2218 UTC. Not seeing an increase in reflecitivity aloft via all tilts in the volume scan after 2218 UTC, but the lightning jump continues to give me more confidence that the storm is remaining severe. Update: 1.00" hail at 2220 UTC. JJW
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