A new squall line is forecast to develop mid-afternoon today in central Pennsylvania to northeast West Virginia and shift eastward and intensify bringing flash flood rainfall and a possible tornado to Maryland and south/east Pennsylvania.

The ongoing severe weather event in the southern states continues to track eastward. According to the HRRR model, peak lightning intensity is around 9PM CDT near Baton Rouge, LA and northeastward to the east of Jackson, MS. The maximum intensity of the squall line is at 11PM CDT stretching from just east of New Orleans northeastward to Birmingham. A lot of severe weather at night – an extremely dangerous combination.

During March, the Madden Julian oscillation (MJO) was strong and caused anomalous convection in the far western equatorial Pacific region. The rising air currents associated with the convection is replaced from the east by increasing trade winds which has up-welled cooler subsurface waters and caused the central/east-central equatorial Pacific to cool restrengthening La Nina.