Adding Confidence With UW-CIMSS Cloud-top Cooling

The AWT Summer Experiment's main objective is to test the Aviation Weather Statement (AWS).  The AWS is a textual and graphical forecast product disseminated to traffic flow management planners concerning weather constraints that are deemed critical to air traffic management decisions.  On Friday June 8th, one of the forecast concerns was if convection would impact the NYC airspace and affect approach gates or the terminals directly.  Coordination between the AWS desk and the GOES-R desk occurred on Friday morning prior to the issuance of an AWS at 1635 UTC (available here).  At that time there was a cumulus field developing between ALY and AVP but no other signals in cloud cooling/growth.  However we did confirm that midlevel air was slightly unstable in this area using the NearCasting model.  The AWS was issued based on experimental model output available at their desk for impacts between 1900-2100 UTC.

Fig. 1 Visibile satellite, UW-CIMSS Cloud-top Cooling, and current severe-weather warnings valid on 20120608 at 1632 UTC.

Just prior to the AWT Summer Experiment daily discussion (early on Fridays since participants have flights to catch), the GOES-R desk noted that clouds were cooling ahead of and along the northern portion of a developing cumulus line to the north-northwest of NYC shown in Fig. 2.  This information was shared in the discussion and the following question was asked to the AWS desk: "Although the AWS was issued a few hours ago, how could the CTC information assist the forecaster issuing AWSs?"  Participants from the FAA Command Center stated that an amended or updated AWS should be issued with the new information that either confirms or updates previous thinking.

Fig. 2 Visibile satellite, UW-CIMSS Cloud-top Cooling, and current severe-weather warnings valid on 20120608 between 1632 and 1945 UTC.

As the CTC algorithm showed convective cooling along the cumulus line between 1832 and 1915 UTC, the strongest cooling was just southwest of ALY, weak radar returns were present in this area but it was difficult to determine which (or all) of those convective towers would potentially grow a strong thunderstorm(s).  The CTC algorithm suggested that the northeastern portion of the cumulus line had the strongest cooling which implies the strongest updraft, and it was that storm that ended up being the strongest (Fig. 3).  It is important to remember when storms form close to the radar that these returns may occur simultaneously to the CTC detection, however the CTC algorithm can provide a quantitative updraft strength that radar cannot provide.  This was another example that illustrates how radar and CTC information can be used together in a convective environment.

Fig. 3 Regional Base Reflectivity valid on 20120608 at 2032 UTC.