The upper level winds in the western portion of Boise's forecast area are showing some upper level diffluence. This is also where some storms are starting to fire per recent radar imagery...
~Lilly Miller~
Thursday, May 5, 2016
Satellite Winds Showing Upper Level Diffluence
The upper level winds in the western portion of Boise's forecast area are showing some upper level diffluence. This is also where some storms are starting to fire per recent radar imagery...
~Lilly Miller~
GOES Winds Estimating 700-300mb Shear - Need More 700mb Samples.
The lower left image shows the 1-minute SRSOR imagery with the GOES winds overlaid. The cursor readout over the far north central portion of the Pendleton, OR CWA shows one sample of winds at 718 mb of 21 knots. It also shows a sample of 362 mb winds of 44 knots. This gives an approximate 700-350 mb shear of 23 knots, which is rather weak. However, sites to the southeast of that area are showing 250 mb winds in the 70-75 knot range. This would give larger shear values from 700-250mb (100 mb deeper than the sample location), assuming the 700 mb winds are similar to the sample point. The lack of sampling of 700 mb winds suggest that this assumption cannot be made. Even so, GOES wind data at 700 mb would be something to watch for as the afternoon progresses. JJW
Pre-Convective LAPS Analysis
As a large upper low swings into California...strong southerly flow is streaming into the Boise area on the upstream side of the upper trough. This flow is ushering in additional moisture but is also increasing upper level diffluence in the region. In the image below...the 12Z BOI sounding is being compared to the 12Z LAPS data (which is mostly GFS output). At 12Z, both the sounding and LAPS shows a very stable environment with positive LI's and zero CAPE.
But by 17Z...the LAPS data is showing some instability in both the CAPE and LI fields as well as an increase in Layer PW. These values coincide well with the 17Z RAP Sounding.
~Lilly Miller~
BOI Mesoscale Update
Stout sw disturbance wrapping up off the SOCAL coast late this morning. Robust jet streak working northward in largely deep meridonal flow pattern should yield convection by mid afternoon invof the northern Snake River Valley especially in light of current clearing across the area and deemed sufficient destabilization.
While GOES LAP derived PW/early morning NUCAPS pass shows limited moisture attm expect improvement through this afternoon as favorable deep southerly flow advects additional moisture north. High based convection will present a limited yet marginal hail threat. However more robust wind threat expected with fairly deep/dry subcloud layer driving effecting evaporational cooling. Will continue to monitor.
Tornadotod
While GOES LAP derived PW/early morning NUCAPS pass shows limited moisture attm expect improvement through this afternoon as favorable deep southerly flow advects additional moisture north. High based convection will present a limited yet marginal hail threat. However more robust wind threat expected with fairly deep/dry subcloud layer driving effecting evaporational cooling. Will continue to monitor.
 |
| 10Z BOI NUCAPS |
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| 16Z GOES LAP/Winds |
Tornadotod
Week 3 Day 4 (05 May 2016) begins
The final day of opreations for Week 3 has begun. Operations shifted to the Western US for the first time this year, with one group in Boise and the other in Pendleton. Guidance from the EFP indicates severe storms should develop across eastern Oregon this afternoon / early evening.
Wednesday, May 4, 2016
Daily Summary: Week 3, Day 3 (4 May 2016)
Today was a very quiet day. One group operated in Florida (Miami and Tampa Bay), monitoring ongoing convection coming off the GoM. The other group operated in the Memphis CWA, tracking sub-severe convection associated with a cold core low advancing through the region.
LAP
- Correctly increased CAPE... GFS has been underdone for CAPE each day this week, so it was nice to see LAP correctly increase the values.
- Clear sky and cloudy sky retrieval values were closer to other data sources than were GFS values.
- Convection developed within the max in LAP PW, which was maximized vertically through the atmosphere at that location as seen in layer PW
- Participants commented that they like the inclusion of GFS model data to fill holes in retreivals
CI
- Pinged development in S Florida
- It worked well for us yesterday.
- There were some that it missed, but there were hits too.
ProbSevere
- Never got out of the single digits. It was still useful information, since convection was not severe
- Having estimates of CAPE and shear were useful
- Confirmed our thinking of what the mesoscale environment would be like
- It did pick out cells within the large cloud shield
- Broadcaster: In my office, we use GR, so we could pull in probsevere files
SRSOR
- In the mid-level cloud plume along the pre-frontal trough, it was helpful to see convective clouds poking through.
- It is helpful to compare SRSOR with radar imagery to match up cells
- I liked the sandwich product, this would be helpful to watch in real-time
SRSOR winds
- The winds nicely showed the shift with drier air moving through.
Lightning Jump
- The few jumps we had were low, which fit the situation.
NUCAPS
- I looked at NUCAPS offshore, which showed drier air aloft, which made sense as drier air was moving in.
- The modified sounding over W TN showed around 500 j/kg of CAPE, which looked right, giving we confidence in how the environment had evolved since 12Z.
- With the Plan view displays it was helpful to see the environment at a particular level.
- With the plan view, you can quickly see how the airmass is changing, more or less stable, based on mid-level cooling temperatures which steepens lapse rates
- The Plan view display is most beneficial in the clear sky pre-convective environment
- I would use theta-e to diagnose areas of CSI and strong frontogenesis.
LAP
- Correctly increased CAPE... GFS has been underdone for CAPE each day this week, so it was nice to see LAP correctly increase the values.
- Clear sky and cloudy sky retrieval values were closer to other data sources than were GFS values.
- Convection developed within the max in LAP PW, which was maximized vertically through the atmosphere at that location as seen in layer PW
- Participants commented that they like the inclusion of GFS model data to fill holes in retreivals
CI
- Pinged development in S Florida
- It worked well for us yesterday.
- There were some that it missed, but there were hits too.
ProbSevere
- Never got out of the single digits. It was still useful information, since convection was not severe
- Having estimates of CAPE and shear were useful
- Confirmed our thinking of what the mesoscale environment would be like
- It did pick out cells within the large cloud shield
- Broadcaster: In my office, we use GR, so we could pull in probsevere files
SRSOR
- In the mid-level cloud plume along the pre-frontal trough, it was helpful to see convective clouds poking through.
- It is helpful to compare SRSOR with radar imagery to match up cells
- I liked the sandwich product, this would be helpful to watch in real-time
SRSOR winds
- The winds nicely showed the shift with drier air moving through.
Lightning Jump
- The few jumps we had were low, which fit the situation.
NUCAPS
- I looked at NUCAPS offshore, which showed drier air aloft, which made sense as drier air was moving in.
- The modified sounding over W TN showed around 500 j/kg of CAPE, which looked right, giving we confidence in how the environment had evolved since 12Z.
- With the Plan view displays it was helpful to see the environment at a particular level.
- With the plan view, you can quickly see how the airmass is changing, more or less stable, based on mid-level cooling temperatures which steepens lapse rates
- The Plan view display is most beneficial in the clear sky pre-convective environment
- I would use theta-e to diagnose areas of CSI and strong frontogenesis.
Week 3 Day 3 Complete
Week 3 Day 3 (May 4, 2016) of the HWT 2016 GOES-R/JPSS Spring Experiment certainly was the quietest day of this 4 week experiment thus far. Particpants worked the Miami and Memphis CWA's. The group in Miami moved to Tampa about midway through the shift. Convection stayed subsevere for both groups.
Quiet days like this, however, do have their benefits. Particpants had ample time to really interrogate each of the products, providing more detailed blog posts than is sometimes possible on the busy days.
For tomorrow, we look forward to moving to the western US for the first time this year.
Quiet days like this, however, do have their benefits. Particpants had ample time to really interrogate each of the products, providing more detailed blog posts than is sometimes possible on the busy days.
For tomorrow, we look forward to moving to the western US for the first time this year.
Overview For Wednesday, May 4, 2016
Today was a day that had weak CAPE (less than 500 J/kg) and modest deep layer shear across the Memphis CWA. A pre-frontal trough slide southward through the area and brought a broken line of showers and some thunderstorms. The storms were relatively weak and did not last too long.
The CI product seemed to pick out some cells that developed into 35 dBZ-plus echoes across portions of the Memphis CWA. The threshold for development seemed to be above 35%, which was lower than the past few days. The convection was relatively low topped, with low freezing levels, so this may have been why CI values above 35% had a good chance of developing. That being said, there were some cells that exceeded 35% that did not develop. Still, the CI product seemed to help deliniate the cells that had a good chance to develop.
The LAP layer PW and CAPE products were helpful with evaluating the environment near the showers and storms today. They gave some confidence that cells may develop south of the advancing pre-frontal trough. In addition, the gradients of the total and 700-300mb PW helped focus areas to watch for future convective development. These products were helpful.
The NUCAPS soundings, once adjusted in the low levels for realistic values, seemed to show representative CAPE and 0C/-20C level values in areas a little southeast of the Memphis area. After comparing to some 12 UTC soundings from representative areas, the NUCAPS values were useful to assess the environment ahead of the showers and storms.
JJW
The CI product seemed to pick out some cells that developed into 35 dBZ-plus echoes across portions of the Memphis CWA. The threshold for development seemed to be above 35%, which was lower than the past few days. The convection was relatively low topped, with low freezing levels, so this may have been why CI values above 35% had a good chance of developing. That being said, there were some cells that exceeded 35% that did not develop. Still, the CI product seemed to help deliniate the cells that had a good chance to develop.
The LAP layer PW and CAPE products were helpful with evaluating the environment near the showers and storms today. They gave some confidence that cells may develop south of the advancing pre-frontal trough. In addition, the gradients of the total and 700-300mb PW helped focus areas to watch for future convective development. These products were helpful.
The NUCAPS soundings, once adjusted in the low levels for realistic values, seemed to show representative CAPE and 0C/-20C level values in areas a little southeast of the Memphis area. After comparing to some 12 UTC soundings from representative areas, the NUCAPS values were useful to assess the environment ahead of the showers and storms.
JJW
End of Day 3
A quite day in the MEG CWA as storms struggled to develop along the western flank of a mid level trough associated with cold core low dropping south out of the Great Lakes. However with that said, GOES CI did do well in depicting eventual development through the central/eastern portions of the CWA by mid afternoon in proximity to maximized GOES LAP derived total PW gradient and where the greatest concentration of storms were observed.
In addition, per general weak cloud growth noted in 1 min SRSOR visible imagery and limited MESH, prob severe remained in the single digits which confirmed the weak/shallow nature of the convection that did manage to develop. Limited lightning production in even the strongest cells did not meet the 10 strike/min minimum for the lightning jump algorithm to activate.
Tornadotod
In addition, per general weak cloud growth noted in 1 min SRSOR visible imagery and limited MESH, prob severe remained in the single digits which confirmed the weak/shallow nature of the convection that did manage to develop. Limited lightning production in even the strongest cells did not meet the 10 strike/min minimum for the lightning jump algorithm to activate.
Tornadotod
Day 3 Wrap Up...Not much to write home about...
Note: The CG Lightning Probability product is not a GOES-R or JPSS funded project.
Well...what can I say... not much convection to speak of today anywhere in the CONUS. There were some thunderstorms that moved through Central and Southern Florida earlier this afternoon but nothing was severe. That being said...I found that the ProbSevere, Lightning Jump and CG Lightning Probability algorithms were still able to pick up on convective cells even in a messy environment. This is very promising!
~Lilly Miller~
Well...what can I say... not much convection to speak of today anywhere in the CONUS. There were some thunderstorms that moved through Central and Southern Florida earlier this afternoon but nothing was severe. That being said...I found that the ProbSevere, Lightning Jump and CG Lightning Probability algorithms were still able to pick up on convective cells even in a messy environment. This is very promising!
~Lilly Miller~
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