Follow Up a Severe Thunderstorm Warning with a Severe Weather Statement - OCLO

Purpose:

This task demonstrates the basic steps of following up the warning with a severe weather statement. This task is only designed for the WES-2 Bridge workstation and not a live AWIPS, to prevent accidental submission. Other WarnGen exercises are also available for use on your local WES machine using WES Exercise #6 (WarnGen).

Tasks:

Assumptions:

• You have created a severe thunderstorm warning in the previous jobsheet and noted your ETN.

1. When on WES you can move your CAVE clock ahead 10min from when you issued the warning to allow you to practice tracking the storm with some new volume scans in your follow up statement.
2. Load WarnGen if it is not already loaded.
3. Select the Severe Weather Statement radio button. We are going to update the warning with a made up report of quarter sized hail 5 min before the warning was issued at a made up location.
4. From the FOLLOWUP pulldown menu, select the CON option on your warning with your ETN.
   • Your Interactive WarnGen polygon should show up.
   • You can also right click on the location of the previous polygon to select a previous warning, but that can behave a little less intuitively if there are multiple polygons overlapping or nearby.
5. In the WarnGen window under basis, select Trained spotters reported, Also select "Select for Observed Hail" and under Additional Reports select "Select to include additional hail and/or wind reports...". The Select for a list of cities option and the (B) Generic threat - standard CTA should be selected by default.
   • Note that we are going to leave the selected hail size as the maximum expected (i.e. half-dollar size from the previous NEW warning) and type in the report manually. If the observed was greater than the hail in the NEW warning then you would need to increase the hail size accordingly.
6. Update the track on your storm.
   • Left click and hold on the “Drag me to Storm” marker and drag it and drop it on the feature you want to track (e.g. hail core).
   • Step back 3-4 volume scans in the main display panel using either the left arrow key.
   • Left click on the feature marker (dot) and drag it and drop it on the same feature you originally tracked in Step 5.
   • Review several frames of the loop forward and backward in time to see if the storm motion vector is accurate for the storm feature you are tracking and that the threat locations ends on the threat you are tracking. 
     • If the track is not satisfactory, navigate to the most recent frame and repeat the tracking steps. Make sure to leave at least a few frames between repositioning the tracking dot to prevent noisy motions.
   • Once you have a good track, step to the most recent frame in the loop.
   • Click on the Track button to preview the polygon extrapolation.
     • Identify the area of the warning using the hatching. If the tracking increased the size of the polygon, you will see some unhatched areas that will be later removed in clipping.
     • Identify the W inside each county within your polygon.
   • Click on the Warned/Hatched Area button to preview the clipping.
     • Identify the counties and cities that should be in your warning. You may want to toggle off the radar data by hitting the enter key on the keypad to see the cities and county names better.
   • Left click and drag your vertices to adjust the polygon to properly contain the current threat and where it is moving.
     • Identify the tip of the arrow of your track which represents the extrapolated location of the point you tracked at the end of the warning time. Do not move your vertices closer than the tip of the arrow unless that extends outside your CWA.
     • It is appropriate to trim the back side of the polygon as the severe weather threat moves out of part of your initial NEW polygon.
7. Left click on the Create Text button.
8. Left click on the Enter button on the AWIPS Header Block window.
9. Read the text of the severe weather statement.
   • You should see a CON segment in your VTEC (e.g. CON /O.CON.KOUN.SV.W.5004.000000T0000Z-130601T0045Z/, and if you trimmed back your polygon in a way that excluded a previous county, you will also receive a CAN segment.
10. Under the SOURCE section replace the framed text with something like "At 705pm...quarter-sized hail was reported 2 miles south of Tonkawa.".
11. Left click on the Send button to begin to send the warning.
12. While on WES-2 Bridge, left click on the Go Ahead! button on the popup message. Left click on the Go Ahead! button a second time.
13. If you want to restart WarnGen after a severe weather statement you have to select a different Product type to activate the Restart button and then click Restart.
14. If you ever need to cancel the entire warning you can select the severe weather statement option and select the CAN VTEC option for your ETN. You will just enter the information about whether the storm weakened, moved out, and if there are any warnings still in effect. 10min prior to the end of the warning the CAN option is no longer available. EXP is a similar VTEC action, but that appears 5min prior to the ending of the warning and is available until 10min after the warning.
15. You will receive more WarnGen practice in the WES-2 Bridge exercises and in the later parts of RAC.
16. Task Complete!