AllSkyLaps_sfc900_vs_700-300 Comparison

Monitoring environment downstream of convection entering FWD forecast area around 1830 UTC on May 2.  Top image is the sfc-900 mb ALLSkyLaps PW illustrating higher moisture over southern portion half of the FWD CWA.  Bottom image is the 700-300 ALLSky Laps PW illustrating much drier air above suggesting convective instability.   SPC Mesoanalysis  RAP downdraft CAPE (not shown) also suggests axis of highest DD Cape in this region suggesting environment supportive for damaging winds as line segments moves across the FWD area later this afternoon. – Quik Twip

Spectacular 1 min GOES satellite imagery of a Colorado supercell

Using feature following zoom to stationary view track a supercell  in ECO. Many things visible here, including uplift and twisting of stratus deck in the inflow region, anvil plume texture, and updraft texture. The parallax error ends up helping the user get more info about the vertical structure and composition of the storm – contrary to the often requested need for ‘parallax corrected’ imagery.

Day cloud phase 1 min of the same storm. Does not get much better than this!

-Dusty Davis

AzShear with a slower moving tornadic supercell and a faster moving outflow dominant cell

This example shows a supercell early in its lifecycle. The cell split and produced a tornado near the county boundary in the loop. In past examples, the AzShear product featured numerous time matching issues from multiple radar site’s data. In this case, cell motion was slower, possibly contributing to the less cluttered and more useful AzShear data.Same loop as above this time with V data. AzShear did anticipate possible tornadogenesis with upticks in values several scans before the tornado. On the bottom left, CPTI is shown for the 175mph threshold. Values for this threshold remained low.

Values readout for the CPTI product on the bottom left at the time of strongest V couplet. Values ranged from 37 for 175 up to 48 for 155, but then did not show much of a change once again between 155mph down to 95 mph. In this range, the probability only rose from 48  to 55 percent between 155 to 95. Then, strangely enough, the prob dropped back down to 53 percent for 80mph.

This later example shows another case of multiple sampling issues with AzShear

 

-Dusty Davis

 

NUCAPS gridded data example

An example of NUCAPS gridded data over Texas. Convection was already underway at this time, as seen by the very high pixels in south OK and north TX. This field is 850-300mb RH. The dryline is evident, however the usefulness of this and other NUCAPS gridded data is questionable for operations because of the poor resolution. With so many other much higher resolution surface and gridded data sources available, I doubt I would be using these products much at all in operations.

-Dusty Davis

PWAT data comparison

PWAT comparison. Allsky LAP is on the top left, Merged TWP is on the top right, and data from GOES that we see in AWIPS in our offices on the bottom left. The blotchyness of the merged product renders it mostly useless for operational purposes. Additionally, the Allsky LAP depicts a much more realistic PWAT spread in north central Texas where convection is ongoing.

 

-Dusty Davis

NUCAPS comparisons – modified versus unmodified

Compared several NUCAPS soundings across the pass to determine usefulness of the modified versus unmodified data. In each example, the modified is on the left and unmodified is on the right. The example above was quite dramatic. This was an example over my home CWA. The modified sounding on the left captures the true mixing likely taking place over the point to the north of GJT airport, the right has a vastly different temp/td profile. This would have dramatic impacts for fire weather and smoke dispersal forecasting in remote areas, which is a critical task provided by our office. 

Moving south, the above example is well west of the dry line in New Mexico. Unmodified does capture a well mixed BL, but the modified shows this feature more pronounced. Clear skies were present throughout the entire day leading up to this point. 

This sounding above was from just slightly west of the dryline

This sounding was a bit farther east, in the vicinity of increasing moisture east of the dry line. Finally this sounding was from well east of the dry line in the vicinity of intense thunderstorm development. Note the odd structure in the lower levels in the unmodified sounding on the left, these strange temp readings are eliminated in the modified sounding which greatly changes the CAPE values and other parameters. 

 

-Dusty Davis

Hypothetical DSS Decision Support Screen – TAE support of Panama City Music Festival

This is an example how the DSS meteorologist could use RGB imagery, gridded lightning products, CG lightning, and range rings for event support.

In this case – we are a HYPOTHETICALLY supporting the Panama City Music Festival denoted by the 10nm range rings.  Process would be to monitor products to predict when lightning is likely to impact an highly vulnerable population.

Layered TPW Shows Arrival Of Moisture

We’ve been monitoring a boundary on both the KEOX and KEVX radar, likely associated with weak surface convergence per surface obs. The layered TPW product shows a tongue of moisture approaching the region. It looks like a line of towering cumulus developed over the Gulf of Mexico as this moisture interacted with the convergence line.Sandor Clegane

NUCAPS – Unmodified vs Modified

Compared the NUCAPS sounding today (4/25) over WFO TAE.  See the point evaluated below (labeled point A below):

This is the “unmodified sounding.”  Overall the thermodynamic profile looked realistic.  Looking in the PBL – noticed it was about 2C too warm and about 2C to dry.

This is the “modified sounding.”  As expected, no change to the mid level thermo profile.  The PBL did have the “correction” applied – not the “cliff” in the temp profile.  Overall, I was expecting a more sophisticated PBL nudging scheme.  In reality – it just appeared to force the T/TD from the nearest METAR, with maybe some minor smoothing.  This is something a forecaster could do in about 30 sec – so didnt gain much.

BETTER OPTION:  employ a more sophisticated nudging scheme to the nearest RAP/HRRR.  If you going to modify the sounding – might as well nudge it to a model analysis – which have a long history of being used in severe wx research.

TAE Mesoanalysis #1

Forcing and storms remain well to the west of our CWA, but the atmosphere is becoming primed for strong to severe storms later this afternoon. LAPS All Sky retrievals show that ML instability has been steadily building, reaching roughly 500 J/kg along the Gulf coast.An 8 hour loop shows how the instability has built and gives more confidence that instability will continue to build ahead of the storms to our west. We did feel that LAPS CAPE seemed a bit underdone given the intensity of the downstream of the convection, so we took a look at the latest NUCAPS retrievals. We examined the point in the extreme SE of our CWA.The boundary layer on the unadjusted sounding required some adjustment to match the nearest obs, but overall, seemed to capture the general profile well. I was initially skeptical about the warm nose just above 700mb, but a similar feature was evident on the 12z sounding from TAE. This feature may have an impact on storm intensity and potential hazards, and it would be particularly helpful to see how this feature changes over time. Sandor Clegane