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A cooperative effort of NASA, the USAF and the NWS
Updated: September 2007
 

Examples of Select AMU Projects

  
The 45th Weather Squadron Launch Weather Officers identified anvil forecasting as one of their most challenging tasks when predicting the probability of a Launch Commit Criteria violation due to the threat of natural and triggered lightning. The Spaceflight Meteorology Group forecasters reiterated this difficulty when evaluating Space Shuttle Flight Rules.

The AMU originally developed the Anvil Threat Sector Tool for the Meteorological Interactive Data Display System (MIDDS) and delivered the capability in three phases from 2000 to 2003. In 2006 the AMU migrated the tool onto the Advanced Weather Interactive Processing System (AWIPS) platform.
  • Phase I established the technical feasibility of developing an objective, observations-based tool for short-range anvil forecasting.
     
  • Phase II resulted in a nowcasting Anvil Threat Sector Tool, which provided the user with a threat sector based on the most current radiosonde upper wind data. The Anvil Threat Sector Tool computes the average wind speed and direction in the layer between 300 and 150 mb from the latest radiosonde for a user-designated station. The following threat sector properties are consistent with the propagation and lifetime characteristics of thunderstorm anvil clouds observed over Florida and its coastal waters (Short et al. 2002):
     
    • 20 n mi standoff circle
    • 30 degree sector width
    • orientation given by 300 to 150 mb average wind direction
    • 1-, 2-, and 3- hour arcs in upwind direction, and
    • Arc distances given by 300 to 150 mb average wind speed.
       
  • Phase III built upon the results of Phase II by enhancing the Anvil Threat Sector Tool with the capability to use national model forecast winds for depiction of potential anvil lengths and orientations over the KSC/CCAFS area with lead times from 3 through 168 hours (7 days). Additionally, the capability to use data from the KSC 50 MHz Doppler Radar Wind Profiler was added to the MIDDS Anvil Threat Sector Tool.
  • For the next part of this work, the AMU migrated the MIDDS Anvil Threat Sector Tool capabilities onto AWIPS as the Anvil Threat Corridor Forecast Tool.
MIDDS Version
An example of the MIDDS Anvil Threat Sector Tool is shown in the satellite image loop below. The threat sector region is depicted by the blue cone-shaped region. On this day the anvil-level winds were westerly with an average speed of 49 knots. The endpoint of the tool is located at KSC and the corridor extends from that point westward indicating if thunderstorms formed in the area of the corridor they would move towards KSC.
  • Frame 1 (1515 UTC) shows little or no cloud over the Florida peninsula.
  • Cumulus clouds begin to develop to the north of the anvil corridor in Frame 2 (1532 UTC) and can be seen moving south-southeast with the low-level winds.
  • By Frame 11 (1745 UTC) some of the cumulus clouds in the northern part of the anvil corridor have grown taller and the higher clouds can be seen moving east while the lower clouds continue to move south.
  • By Frame 17 (1945 UTC) the thunderstorms near the 1-hour arc are producing anvil clouds and they can be seen moving toward the east along the anvil corridor towards KSC.
  • By Frame 21 (2045 UTC) anvil clouds have reached northern KSC and in subsequent frames the anvil clouds can be seen moving rapidly eastward.
AWIPS Version
An example of the AWIPS Anvil Threat Corridor Tool is shown in the satellite image loop below. The threat sector region is depicted by the red cone-shaped region. On this day the anvil-level winds were westerly with an average speed of 25 knots. The endpoint of the tool is located at KSC and the corridor extends from that point westward indicating if thunderstorms formed in the area of the corridor they would move towards KSC. In the example on this day, the Florida peninsula is experiencing strong low-level easterly flow with upper level westerly flow.
  • Frame 1 (1731 UTC) shows an area of enhanced cumulus clouds with rain showers aligned north-to-south along the center of the Florida peninsula.
  • The clouds continue to grow as they move westward in the low level flow and by frame 5 (1901 UTC) an anvil can be seen at the 1-hour arc in the southern corridor.
  • By Frame 9 (2001 UTC) the anvil that formed around 1901 UTC has progressed to the western edge of KSC where it dissipates.
  • Throughout the rest of the loop, other anvil clouds can be observered developing along the north-to-south line of clouds and moving east along the corridor as the low level clouds continue to move westward.