Models have been consistent in bringing a low pressure system from the south that has been causing flooding in Texas and Louisiana to Southern Ont tomorrow.  Its been hard to take the models seriously since they have been crying wolf all summer long.  What they can’t agree on is the exact placement of the low.

The GFS model has the main system crossing north of the GTA, in almost the exact same spot as the system that went through Saturday.  Basically a line from Georgian Bay, across central Ont, Bancroft to the Ottawa Valley into Southern Que. would get the heaviest rain:gfs_mslp_pcpn_frzn_us_5

The CMC model that Enviro Canada uses is a little farther north with the bulk of the moisture further north in central Ont, from North Bay eventually into the Ottawa Valley:I_nw_EST_2016081512_031

The NAM model is further south, with the heaviest rain through Southwestern Ontario into the GTA and along the shore of Lake Ont towards Central Ont :nam_namer_030_1000_500_thick

What is clear;

  • everybody in Southern Ont & Southern Que will get some rain, starting from tomorrow AM and later Tuesday afternoon/evening in the east.
  • likely the bulk of the heaviest rain will miss the Niagara Peninsula and around the GTA.
  • where the rain is the heaviest, amounts will likely be over 30mm, possibly up to 60 mm.
  • this is a welcome event for the farmers who have a last ditch chance to improve corn and other crops for the year.
The rest of the week should fairly warm with some humidity but the extreme heat is gone.  Some models are trending back to near normal next week, almost cool like,  as our daytime highs start to drop off with the sun starting its lower angle journey.  More later on the long range.