Tuesday, April 30, 2019

GLM on developing storm



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. 



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

-Jake Johnson

Situational Awareness Smorgasbord

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

Washington County SC Upgraded to Tor

Prob Tor up to 88% with 63% CPTI 80 mph winds.  AZShear has been very persistent  last several Volume scans and Z/SRM suggested tornado .  WARNGEN would not issue TOR got error but tornado warning out! 

Quik TWIP

SC Entering Washington County

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

NWS Forecasters Data Usage and Access

An interesting point that has repeatedly come up, both during the EWP debrief as well as during discussions on the forecast desk, is related to how NWS forecasters view and access data pertinent to their jobs.  A number of forecasters have stated they often use the software GR2 Analyst to interrogate radar data and display ProbSevere data.  Additionally, forecasters have discussed how they often use the web for a variety of data--including NWP data and ProbSevere time series for storms of interest (Figure 1).

Figure 1.  ProbSevere time series for a storm of interest over Oklahoma available from the ProbSevere website
The ability to display ProbSevere time series information has been a common feedback point from previous experiments.  The ProbSevere team is working on adding this ability within AWIPS-II.  The group this week is excited to hear about the capability will be added to AWIPS-II for ProbSevere, however they also expressed some concerns.  Many forecasters shared experiences of AWIPS-II slowing down with so much data loaded and expressed the need and desire for capable displays being available on the web, etc.  While this is a larger topic that crosses the intersection of policy, user needs, and technology, among many other aspects--it seems forecasters often need to balance AWIPS-II data load (for usability/speed concerns) and using alternative data display methodologies (e.g., GR2, web-based, etc.) to achieve that balance.

J. Sieglaff

Meso-analysis for CI


Figure A


Figure B

Watching for new storm development in SW Oklahoma with GOES-16 Vis/IR showing a new storm developing in Figure A.   Area of interest will be in southwest Oklahoma with frontal boundary stalled out and high CAPE from All Sky Layer in Figure B(left image) meanwhile right image shows All Sky Layer PW with RAP13 0-3km CAPE in black contours.  This environment would be favorable for severe weather and possible tornadoes if storm can remain on the frontal boundary.   

-Jake Johnson

That's Not My CWA - But Still a Nice Above Anvil Cirrus Plume

Nice AACP with the severe cell over Osage Co OK. Thermal couplet had a min of -73C and a max of -57C.  Also a weaker AACP on the cell moving out of NE OK.

GLM lightning minimum with rapidly developing supercell



This rapidly developing supercell displayed a GLM lightning decrease as it intensified. This was a good example of optical attenuation due to an updraft core. ENTLN network is displayed, showing that there was a tremendous of CG and IC flashes despite low GLM values. Shown is the TOE product.



The same storm and lightning minimum shown in Event Density.



ProbTor was occasionally too aggressive. Only one of these storms was really concerning at this time given the environment and radar tilts further up in the volume. On a day like this, it would likely be prudent to increase the probtor threshold above 3%

Contours-a-plenty in ProbSvr

ProbSevere double contours were plentiful at this time showing the utility that certain "big" days may need to be modified to increase the threshold for the second contour. This was the default 3%.  Only a couple of the circulations were worth investigating in reality.



-- S Coulomb

Week 2 Day 2

Today figures to be an active day across the southern plains. We will be operating across Oklahoma and Missouri today monitoring for storms capable of all hazard types.

-Michael