A stalled weather pattern led to persistent showers and thunderstorms moving up the eastern seaboard last week, resulting in significant rainfall amounts and numerous flood warnings. A nearly stationary elongated upper-level trough of low pressure stretching down from the Great Lakes to Florida combined with a persistent Bermuda High off the coast to channel a steady flow of warm, humid air up the eastern seaboard. The result was a week of re-occurring showers and thunderstorms across the region.
Flood watches and warnings have been issued today for states from North Carolina through New York. Major flooding of rivers and streams is forecast in Pennsylvania as heavy rainfall continues. A Large blocking high located east of Nova Scotia and Low Pressure over the upper mid west has been funneling moisture over the Mid-Atlantic states. This weather pattern includes a strong upper level trough with it’s axis becoming oriented from the Great Lakes through the eastern Gulf Of Mexico.
Tropical storm AMPIL was moving toward the northwest with winds of about 50 kts (57.5 mph) when the GPM core observatory satellite flew above on July 20, 2018 at 0656 UTC. Data received by the satellite's Microwave Imager (GMI) and Dual-Frequency Precipitation Radar (DPR) instruments were used in this analysis of AMPIL's precipitation. GMI and DPR showed that the northern side of the tropical storm was nearly dry and that rain bands in that area were producing only light to moderate rainfall.
India's southwest monsoon (summer rainy season) normally occurs between June and September. This year's monsoon has been assessed as average but India's Meteorological Department statistics show that daily mean rainfall for the country has recently been above normal. At least 15 people were killed by floods and landslides in India on Wednesday July 11, 2018. So far this year, close to 200 deaths may have resulted from India's heavy monsoon rainfall.