After all this rain, why is there no change to the current Drought Monitor for us?

Weather Blog

ROCHESTER, NY (WROC) – Over the past 4 days Rochester has received more rain than it has all month long with daily rain totals ranging from a quarter to well over an inch in some places across the region. Believe it or not it’s been all the way since early August that we’ve seen a 4 day stretch filled with raindrops. It doesn’t seem like much, but with parts of the region under a moderate drought, getting all this rain was very beneficial.

Now despite this recent uptick in moisture, there was little change to the most recent drought monitor that was issued just this Thursday morning for New York State, and practically no change at all to us here in western New York.

Photo courtesy: droughtmonitor.unl.edu

Notice how little these two images have changed with the left image showing October 13th’s update, and the image on the right showing the 20th’s update.

The little to no change all comes down to the timing of the rain and when the US Drought Monitor updates. First let’s talk about the rain we received.

. . .

The relief from our lack of rain this month began on Monday the 19th, where the Rochester airport finally received a total of 0.44″ of rain. On the 20th we received 0.34″, and yesterday, a grand total of 0.69″.

And those were just the totals recorded at the Rochester airport in Monroe County. There were many other totals that were much greater than that, especially when you add it all up from the past several days. Here are the highest 24 hour rain totals recorded in each county released from the National Weather Service in Buffalo just from Tuesday the 20th:

County           City/Town          Rain Total

Genesee         Alabama               0.75”

Livingston     Hemlock               0.90”

Monroe          Rush                      0.87”

Ontario          Honeyoe               0.85”

Orleans          Medina                  0.73”

Wayne            Wolcott                 0.92”

Wyoming       Portageville           1.11”

Based on the grand total of rain recorded at the airport, we were still running a slight deficit for the month of October up to the 20th, sitting at -0.52″ below normal.

However, when you add up the additional amount of rain we received after the 20th, you get around inch of rain, so the deficit for the month up to that point should have been well taken care of. With this in mind the drought monitor was sure to show some change, but it didn’t.

So why didn’t the map change?

Photo courtesy: droughtmonitor.unl.edu

It comes down to the fact that Tuesday, October 20th at 8 AM was when the drought monitor data is actually updated, but the map itself doesn’t become available to the public until Thursday morning the 22nd. This means any additional rain received after the 20th isn’t being accounted for in the newest update. Between the 20th and today, we actually received the most rainfall within these past 4 days that would more than likely give us a good chance at getting at least some improvements on the drought status across the area.

So even though our additional inch or so of rain recorded over the past 2 days at the airport wasn’t counted in the latest drought monitor, let alone the other abundance of rain totals, ever since yesterday we finally started running a surplus of 0.34″ above normal for monthly rainfall.

Which means it’s more than likely the next update issued on the 27th, but available on the 29th will show some signs of improvement to our drought-like conditions across the region.  

~Meteorologist Christine Gregory

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