There were a few hints Tuesday evening Thursday rainfall amounts might be coming down a little in model forecasts. Alas, they are back up again in newer runs on Wednesday. Moderate rain will develop toward midday or sooner on Thursday, with heaviest amounts having fallen by evening. In the medium resolution NAM model, the steadiest soaking rain will be with us toward evening, with the low pressure system depicted as having passed just to our south near the PA line.
Check out the rainfall totals predicted in this model by late Thursday night. Up to 1 inch could fall on parts of the Niagara Frontier, with the least falling closer to Lake Ontario. Up to or over 2 inches, a troublesome amount, could fall in parts of the Southern Tier, in this medium res model.
But these amounts and placement are far from carved in stone. The higher resolution version of the NAM has a different idea, bringing the heaviest totals farther north, up to and including the metro area. The high res model is faster with the low, and tracks it a little farther north even before late morning … quite a difference.
This model brings the heaviest amounts, in excess of 2 inches, up to much of the Niagara Frontier. I’d like to toss this high res model out as an “outlier,” but the newest version of the GFS also takes the low a little farther north, as does the Canadian GEM. And, the GFS also brings the heaviest rain up to the Niagara Frontier, rather than the Southern Tier. All that said, the high-resolution amounts may be a little on the overdone side, but a soaking rain still appears likely. To go with this will be a chilly NE wind by afternoon, which will likely cause problems along the Lake Ontario shoreline.
Here is what National Weather Service headquarters is thinking for rain totals. However, the newest high resolution model I showed you above had not yet run when they put out this forecast. The tendency this spring has been for the heaviest rainfall to fall mainly on the Southern Tier, as depicted in this NWS product. However, this time around, my thinking is they’ve got that heavy rain displaced a little too far south. Bottom line is that amounts won’t be quite as heavy as in the high-resolution NAM, but they will be farther north than in the NWS graphic. I guess that makes ME an outlier.
“The good news is…” a longer-term, more summerlike pattern change is on the way, which will be covered in a separate article.