Excel look up

This is hopefully straightforward. I require an Excel macro to look up a list of two columns. Column A presents changing values and so does column B. When the value in column A reaches 20 or above for the first time, I want to find the lowest value in the adjacent Column B until the values end in the list. The range for the lowest values must start one row below when the value of 20 or above is found. Here is an example assuming that the first value above 20 is found in cell A5 (and is equal to 22) and the last value in Column A is in cell A26 (and is equal to 44). I would want to find the lowest value in the range B6:B26. The lowest value in range B6:B26 is 12. Then I would want the last value in the list in column A to be recorded as the “Close” value. The result would be: Lowest = 12 (lowest value in range) Close = 44 (last value in Column A) I would want this done also for the first value above 30 in the list. Also, where the is no data (ie. The value in cells in column A do not reach 20 or 30), then I want “No data” put in the results. It may be that there is data for above 20 but not above 30 also. Hopefully, the 3 attached examples show this better. To note, that the input may vary in length but the values will never go beyond 400 rows.