MOD. RISK!

A very serious situation is unfolding today for our area, with the Storm Prediction Center placing us under a MODERATE RISK zone. To put this in perspective as to how rare this type of severe weather outlook is for our area, I can only remember 1 other time during the lifetime of grotonweather.com that we have been under a moderate risk, and NEVER have we been under one to start the day! I do have to say, however, that I was thinking last night that this would happen. Here are the areas under the moderate risk (pink in the top image) because of the wind threat (red in the bottom image).


As I have been indicating the past 24 hours, everything is coming together for a major severe weather outbreak. Hot, humid air is and has been in place. This will interact with a cold front and trough of low pressure that will progress eastward through the day. The final piece to the puzzle will be the strong jet stream winds. The thunderstorms that explode later this morning across Western and Central New York will be able to tap into these winds. Winds in some of the storms today could exceed 70, even 80 or 90 mph. The tornado threat is a tad higher than I thought last night as well. I will be updating throughout the day, so make sure to stay tuned here for the most up-to-date, in depth forecasts and outlooks you will find on the web for this area!

(Your normal forecast will be coming by 8AM. To find the forecast, hover over the "Grotonweather" tab in the menu above, then click the "Homepage" link!)

Round Two Begins!

The clusters of thunderstorms that moved through earlier today have shifted well off to the south and east. While these storms stabilized the atmosphere for a while, in the long run, they only made things worse. Over an inch of rain fell in Groton earlier. Now, with the sun back out, that inch of rain is returning to the atmosphere. Dewpoints have shot up into the mid to upper 70's, making it feel over 90 despite temperatures being in the low to mid 80's. All this moisture is fueling another round of thunderstorms which is just now starting to explode.

Right now, most of these storms are in the southern counties of New York, but there is a large cell over Lake Ontario as well. Further rapid development of storms is certainly possible over the next few hours. There is currently (4:30) a small cell near Trumansburg that will have to be watched for rapid development in the next hour or so. A severe thunderstorm watch remains in effect as well.

Looking into this evening and overnight, there is a very strong line of severe thunderstorms over Michigan right now. These storms have a severe thunderstorm watch for Michigan, and a torando watch issued by the Canadian Weather Service for Southern Ontario. It is hard to say if this line will hold together long enough to effect us, but it is something I will be watching through the evening.

On this radar image (from weathertap.com) you can see the numerous cells firing up in New York, along with the line of storms in Michigan marching eastward.

Storm Reports, May Stats

While there wasn't a whole lot of widespread severe weather yesterday across Central and Western New York, the one area that did seem to get hit hardest was in fact our area. Most of the grotonweather.com forecast range (Tompkins, Cortland and Southern Cayuga Counties) ended up under a severe thunderstorm warning at one point or another as two separate severe storms crossed the area.

The first storm tracked across Southern Tompkins and Cortland Counties in the early afternoon, well ahead of the cold front. This storm produced numerous hail and wind reports, especially once it moved into Broome and Chenango Counties. The second storm came through at about 6pm. This storm took out trees in Cortland and Locke, while hitting West Groton with 3/4" hail, with some smaller hail in Groton.

I have overlayed yesterday's storm reports on Google Earth and marked a few of the towns for reference. The blue circles with a "W" represent a wind damage report, while the green circles with an "H" represent hail. Not a huge outbreak by any means, but considering the lack of severe storms elsewhere, we got hit decently hard.


Onto other things now...did you think May seemed abnormally cold? Well, if you did, you are correct. In fact, the differences between this May and last May are quite staggering. Our average high this May was a very chilly 64.0 degrees. This ended up 12 degrees colder than last May, which averaged 76.1 degrees. In fact, there were only 3 days in which our high this past month reached 76 degrees! (Those days were the 7th at 76, the 26th at 82, and the 31st and 76). Our warmest day this May was 82, much lower than last year's 92 and even lower than 2006's 95 degree day. On the whole, it was the coldest May on my records (2003-present) by three degrees. We also had our coldest nights, with our average lows falling below 40 for the first time.