Wednesday, April 30, 2014

Heavy rain & flooding

Heavy rain is producing major flooding along the Gulf Coasts of Florida and Alabama. Downtown Mobile above from Twitter - Casey Toner -
The pesky low pressure area that has been causing so much deadly weather across the US is still slowly moving east from the Great Lakes. The system produced another day of strong tornadoes across the southern US stretching on Tuesday north towards the southern Great Lakes. Thunderstorms even fired up in southern Ontario yesterday afternoon with heavy rain and small hail. The death toll since the weekend is well over 30 now in the US. Yesterday a new twist was added to the storm with heavy, flooding rains across Florida and Alabama. Coastal areas of both states received an unbelievable 500mm of rain in less than 24 hours (over 20 inches). To put that into perspective, Montreal is under a heavy rain warning for the next 24 hours with 25-50mm possible, that is only 1-2 inches, and watch how hard it rains tonight. That will give you a good idea of the deluge that must have fallen in Mobile, Alabama and Pensacola, Florida Tuesday and last night. Needless to say widespread flooding has occurred with numerous water rescues and 1 fatality. Roads including Interstate 10 in Florida remain closed as flood waters slowly recede today.

More rain is in the forecast for the southern US and is stretching north towards southern Quebec. A deep plume of tropical moisture will overrun the east coast and St. Lawrence Valley tonight with rain and perhaps some thunder into Thursday morning before tapering off. A heavy rain warning is in effect for southern Quebec this afternoon and tonight. Normally warnings are issued for 50mm in less than 24 hours, but I believe in this case the concern for flooding in southern Quebec remains elevated, thus the warnings.
Temperatures will be cool today in Montreal at 8C with northeast winds. Tonight cool and damp with lows of 5C. On Thursday, if we are lucky, a few sunny breaks and a warmer south wind may drive the temperature up into the high teens (19C) in Montreal.

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