+CG Denotes Positive cloud to
ground strike -CG
Negative cloud to ground strike
+IG Positive intracloud strike -IG Negative intracloud strike
Nexstorm software produces an identifier which you will see next to a colored circle.
The format is: A-NNNN- or + S and ^ - v (EX: W2647-9^)
The First letter and next 4 numbers are uniquely generated for each storm based on time of detection.
The -/+ indicates dominating strike polarity, the S is the number of strikes per minute for that target. And the ^ or v indicates if the storm is increasing, steady or decreasing.
So for the example above, W-2647 is the storm ID, it's Negative Polarity, 9 strikes per minute, and increasing.
The Storm circle colors indicate:
Circle Strike Rate/Min Classification
Green 1-10 Weak
Yellow 11-49 Moderate
Red >50 Severe