Category: Live Blogs

Real-time posts made during testbed nowcast and warning operations.

Situational Awareness Smorgasbord

Posted in Live Blogs on by Tiffany.

Beginning to see CI in the southwest portion of OUN’s CWA. ProbSevere has progged a 3-4% tornado probability for two areas: the SW storm and a few weaker/young storms in the central CWA. GLM minimum flash area along with total optical energy clearly indicate that the SW storm is the most promising of the two with more persistent updraft(s). Subsequently, 0-2km merged AzShear has perked up with the storm in the southwestern portion of the CWA. Given the storm’s favorable environment (ample 0-3km CAPE, bulk shear, and SRH), this storm warrants watching. Based upon the combination of GLM data, ProbSevere/AzShear, and 1 minute satellite imagery, a forecaster can quickly hone in on the most pressing storms at the moment.

–Stanley Cupp

1937z KFDR base reflectivity with ProbSevere overlays (double contour –> tornado prob progged)

Top left: MRMS RALA; Top right: visibile sat plus 1 minute minimum flash area; Bottom left: 5 minute total optical energy w/ 1 minute updates; Bottom right: 1 minute total optical energy

0-2km merged AzShear

 

Posted in AzShear, Live Blogs on by Tiffany.

 

Figure  1936Z

Thunderstorm developing in southwest Oklahoma along 0-3km CAPE boundary with GLM showing first signs of lightning.  If this storm remains attached to this boundary the environment supports possible tornadic development.  ProbTOR is showing 3% with this early development Figure 1936Z.   -Jake Johnson

 

A positive for AZ-Shear product it does not show range folding like base velocity/SRM products.  Might be useful tip.  -Jake Johnson

 

SC Entering Washington County

Posted in AzShear, HWT, Live Blogs, ProbSevere on by Brandon Smith.

This storm has had consistent Azhear max for past several volume scans, but again does not seem to match low-level SRM scans very well. Prob Tor has increased and remained steady at about 75 to 77 % CPTI has remained slightly over 50%. Upgraded SVR to Tor possible. Reflectivity structure suggests increasing organization with well organized ZDR arc arc suggesting increasing SRH. May upgrade to tor shortly given better storm structure in base data. Quick Twip

Advantage of AZ Shear

Posted in AzShear, HWT, Live Blogs on by Justin.

Favorite part of the Azimuthal shear product so far is it can highlight some areas of the storm that need to be investigating…if you are watching a different storm and want to do a quick look at your CWA this can grab you attention to a storm that needs to be looked at next.

South Beach

All-Sky LAP CAPE and Boundaries

Posted in Live Blogs on by Tiffany.

The All-Sky LAP CAPE product is rather useful as a quick and dirty SA tool to quickly identify boundaries and their approximate location/orientation. While the actual CAPE values given are not as important (perhaps better to rely on obs, mesoanalysis, and short-term models for that), the LAP product does very well with identifying the key location of the gradient and subsequent boundary. The boundary location in today’s case is rather obvious, but this product will likely prove useful in more diffuse situations.

–Stanley Cupp

ProbSevere MouseOver

Posted in HWT, Live Blogs on by Michael Bowlan.

ProbSvr readout is becoming so long it is hard to fit within a 4_panel. It is not usable as a readout in a 9_panel due to the number of parameters being shown. Perhaps combine the LLAzShear into a single line such as (Max,LLA,MLA) (0.004/s,0.0002/s,0.005/s) to save space???

— S Coulomb

NUCAPS Soundings

Posted in Live Blogs, Mesoscale Discussions on by Michael Bowlan.

While it is very easy to plot forecast soundings from whatever model you may choose, NUCAPS provides yet another resource as an alternative to NWP. A strong thunderstorm formed in Mexico around 22z today, almost due west of Del Rio, TX. SPC mesoanalysis showed approximately 2000-3000 J/kg of MUCAPE in the vicinity prior to convection initiation (CI). A quick look at a 20z modified-NUCAPS sounding corroborated the SPC analysis, with ~2400 J/kg of MUCAPE at 20z. The NUCAPS data allow for a detailed analysis of the resulting profile and can be a useful alternative to model soundings, especially the modified products as they attempt to more accurately represent the boundary layer based upon RTMA data. The 20z NUCAPS had ample CAPE in the hail growth region along with 700-500 mb lapse rates in excess of 7C/km. Effective bulk shear in excess of 40 knots coupled with favorable thermodynamic environment likely resulted in this storm producing large hail as KMAF radar sampled greater than 60 dBZ at greater than 32K feet. ProbSevere hail output peaked at 97% (MRMS Mesh = 1.87″) roughly 40 minutes after CI.

–Stanley Cupp

20z NUCAPS sounding near storm in Mexico

20z SPC Mesoanalysis MUCAPE and 0-6km shear (dot indicates point of CI)

Mexico splitter – Prob Severe and GLM data

Posted in Live Blogs on by Michael Bowlan.

Loop showing the evolution of a strong cell west of Del Rio in Mexico. Prob Severe values were dominated by Prob Hail in this case. This hail threat makes sense given mesoanalysis and storm mode, supported by 12z Del Rio sounding. Peak values around 97% occurred before the storm split, but after peak dbz values observed on radar. This makes sense considering the beam height at this range (165 mi from MAF) was showing the mid-level core at 30kft MSL – hail would likely have needed time to fall out from this height. This case could be useful for offices with high radar beam heights distant from isolated thunderstorms. Prob Tor did nudge up around the time of the storm split enough to show the ‘double contour’, however V data at low levels was not present.

 

Same storm now with GLM Event Density. This data showed a lightning decrease around the time that the storm split. Following the split, almost 0 lightning was observed in the southern cell, while the left split saw a spike in event density. The left split reinvigorated shortly after the split while the right mover weakened.

 

This is the same loop with radar overlaid that shows the storm split and this time flash extent density. Almost 0 lightning data seen in the south cell.

Brewster Co TX storm not so Punky but modified NUCAPS was

Posted in HWT, Live Blogs on by Michael Bowlan.

The modified NUCAPS sounding over Brewster Co TX was more representative of the actual conditions at 20Z versus the regular NUCAPS. A dryline was positioned very near the point of interest and convective initiation eventually occurred  near the boundary in ~1000 ML CAPE air around 22Z.

Modified NUCAPS sounding w/ surface Td near 47F. MLCAPE ~ 1000 J/kg.

Regular NUCAPS sounding w/ surface Td near 54F. ML CAPE ~2000 J/kg.

RTMA Td analysis. Point H is where the NUCAPS sounding was taken from.

GOES-16 RGB at 2150Z showing CI occurring near the dryline.