Tropical rains

Major flooding in Wilmington after 10 inches of rain yesterday.

Deep tropical moisture is streaming northward along the entire east coast this morning. The rain has been heavy at times in the region, with warnings in place north and west of metro Montreal. Around 10-20mm fell overnight with another 10-20mm expected today, with more where any thunderstorms occur by afternoon. This morning low pressure is near Lake Erie, and it will move north to lie near Ottawa later today. Montreal is on the warm side of the storm with the temperature expected to climb to at least 23C despite the clouds and showers. It is a muggy, tropical air mass, which can be felt this morning, with our temperature already above the normal daytime high for late September, at 18C.

Along the east coast the heavy rain has produced major flooding. Flood watches are in effect for the Washington DC area with warnings across the Carolina's. Yesterday Wilmington, NC had almost 10 inches (250mm) of rain the second heaviest recorded in a 24 hour period. The culprit is tropical moisture being fed north from a developing low pressure near Jamaica. A NOAA reserve hurricane hunter is scheduled to fly into that system today with the National Hurricane Center predicting and 80% chance it will become a named storm this week. There is concern from Florida towards the middle Atlantic that this system will produce even more heavy rain on already saturated ground. That story will play out as the week progresses. Locally the clouds and wet weather will continue well into Thursday before some clearing and cooler weather will move in. That forecast depends on the southern system.

** It has been a cool summer along the southern California coast, however that changed yesterday. Despite it being fall, Los Angeles recorded its warmest temperature ever at the USC station, with a high of 113F at 12:30pm. A half hour later the thermometer broke, so it may have been even warmer. That high was the warmest since record keeping began in 1877, and it surpassed the previous high of 112F set in 1990. It will be "cooler" today at 100F.