NEW YEAR, NEW WEATHER PATTERN

Written By: Scott Hetsko

A strong cold front will cross the region Friday afternoon and bring in much colder air over the weekend. At the same time, a coastal low will stall and may move back toward the Southern Coast of Maine Sunday morning. I'm confident in saying that significant lake effect snow will fall over the weekend for most areas North of the thruway and here's why...

A stalled low feeding moist, cold air over Lake Ontario could mean significant snows in Rochester on Sunday. There will be lake snow warning posted over the weekend so please check back on Friday as we will begin to put some numbers on the upcoming snow. My gut feeling is that at least 6-12" is good bet throughout the weekend with some areas getting over 12" by Monday morning.

Some of Rochester's biggest snows come from "Lake Enchancement" rather than pure "Lake Effect". This is the case setting up on Sunday. Bitter cold air and strong winds will combine to make the upcoming weekend the coldest and most wintry so far this season! HAPPY NEW YEAR TO ALL!!!!

WESTERN NEW YORK WEATHER 2009 YEAR END REVIEW

(Image from NWS Buffalo of hook echo from the Hilton, NY Tornado)

Written by: Brian Neudorff

Here we are closing out another year and 2009 had some interesting weather events across Western New York. I am going to list a few starting with January and working towards the end of the year, and if I missed one, please add it to the list and give your thoughts.

January Cold and Lack of Winter February & March:
I think I know now why many of our commenters really miss winter and want a really big snow. January was very cold but never really produced an big storms then as we went into February and March winter just seemed to end. Both were below on snow and above on temperatures

Taste of Summer to End April:
At the time it didn't seem that big of a deal, it felt wonderful. Maybe you remember it from April 24th through April 27th three of those four days the high temperatures climbed into the 80s with the warmest on the 27th at 85. At the time, didn't think it was that big of a deal, but who would have imagined that those three 80+ degree days and three more in May would equal the total 80 degree days in June and July.

Lack of Summer, cool & wet June & July:
You knew this was coming, it was one wet and very cool summer in Western NY.

...COOLEST JULY IN 125 YEARS (66.2)...2ND COOLEST EVER (TO 65.4 IN 1884).
...COOLEST JUNE-JULY COMBO EVER (64.9). NEXT WAS 65.1 IN 1992.
...COOLEST YEARLY MAX TEMP EVER THROUGH JULY...86 ON 6/25.
...FEWEST 80+ DAYS THROUGH JULY..12. NORM 35. (PREV MIN 15 IN 1926)
...FEWEST 86+ DAYS THROUGH JULY..1. NORM 15. (PRV MIN 2 IN 1958,2004)
...FEWEST COOLING DEGREE DAYS THROUGH JULY...144. NORM 356.

For the 2 month period June and July were 4.29" inches above the normal rainfall.

It wasn't until August, and for only 13 days that we experienced "true" summer weather. Between Aug 10 through the 22nd and 12 of those 13 days were in the 80s and one (Aug. 17) hit 90.

5 Tornadoes in Western New York:
Getting tornadoes in Western New York and to have 5 during fairly cool summer is pretty rare. The first 2 occurred on July 25th through Darien and the Village of Corfu then later in the evening Hilton. The Darien/Corfu tornado was classified as an EF-1 with est. max winds of 100 mph. Damaging 25 to 30 homes. The Hilton tornado was classified as an EF-0 with est. max winds of 75 mph.
The third tornado took place the next day on July 26th in Cattaraugus county near Onoville. It was an EF-1 with est. max winds of 90-95 mph and had one injury reported.
Forth occured on Sunday August 9th as a series of severe weather events unfolded across western New York State. A combination of severe thunderstorms with damaging straight line winds and a confirmed tornado pelted the region during the afternoon hours. The tornado touched down near New Hudson-Cuba, it was an EF-1 and had ext. max winds of 100 mph.
The fifth and last one was the tornado that touched down in Canandaigua and did extensive damage to boats around the Canandaigua Yacht Club. It was an EF-1 est. max winds of 90 mph.

Gowanda Flash Flood:
The evening of Sunday, August 9, 2009 some of the highest short-term rainfall totals ever recorded in western New York occurred. Those rainfall totals resulted in the worst flash flooding the area has seen in decades. Roughly 6 inches of rain in a 3 hour period not including rain that are received earlier in the day. In addition to preliminary estimates of tens of millions of dollars of property damage, the flooding also resulted in the direct loss of one life and indirect loss of another that night.

"NO" vember Snow:
There was no measurable snowfall in the month of November, first time that has happened in November since 1952. We also went 237 days without snowfall the 4th longest streak in Rochester's recorded history! (April 7th until Dec. 1)

Those were some of the highlights I could think of, maybe you have one or two that I didn't think of. Please share. I hope everyone has a wonderful New Years and here is to a great 2010.

WEEKEND LAKE EFFECT DISCUSSION

Written by: News 8 Weather Team

First and foremost, we'd like to discuss the aim of this blog. We created the weather blog in hopes of providing the public with a behind-the-scenes, more in-depth look at what our thoughts are about upcoming or occurring weather. We provide insights as to model data, as well as our own "gut" feelings. We've all got some experience and reason for the thoughts we put into our forecasts.

Recent comments have compared our forecasts to other stations, or criticized our accuracy. We aren't competing. Our forecasts are our forecasts, and no one elses. Weather forecasting is and will NEVER be an exact science, therefore you will always see variations from one station (or one meteorologist) to the next. And yes, we will have errors. There, we said it!

With the anonymity of the blog-o-sphere, anyone can post anything at any time about anyone else. We understand that everyone has an opinion and we respect that. We're also very glad you care enough to check this blog out and participate. Just please remember that we are here only for the purpose of expanding upon our thoughts that we could never possibly cover in a 3 minute weathercast, as much as we'd like to. We hope you continue to enjoy, and that you respect us the writers, as well as all of our readers out there. We love the recent increase in participation here, and hope it only continues to grow.

Okay, now to this weekend's lake effect. Potential is definitely there, there's no doubt about it. Nice cyclonic curvature overhead, an 850 mb low to our east, and a favorable wind direction.

I guess what I want to clear up is the size of this event. We'll all get a good dose of snow, that's not the question at hand. It's that we won't see "historic" or "major" snow. The ideal direction for blockbuster lake effect here is northeast as mentioned before. We've had plenty of occasions where good snow results from a northwest wind, and this weekend will probably be one of them. So while you may need the shovel, you won't be needing your next door neighbors 26 hp John Deere snowblower to escape the driveway.

I took a look at the 1000-850 mb average RH, and its decent, but not impressive. In comparison to the lake effect "event" (if you can call it that) of a few days ago, this next go-around will be something much better, as far as moisture characteristics go. Slower winds will be able to grab more moisture, and the temperatures aren't quite as cold, which means that the air has more moisture-holding capability.

Why aren't we posting the when/where/how much yet? It's too early. The models are really fighting over the placement of this low off the northeast coast, and even then, the thing takes a little joyride around the northeast maritimes. The direction of the winds will have a huge bearing on snow location and amounts. We'll keep you posted.

As I finished this, the data for the 18z NAM came in. Two thoughts:

This is for late Friday night. Good northwest flow, which could set us up with an upstream connection to Lake Superior. Several hours of decent lake effect favoring northwest/southwest areas of Rochester. But it moves quickly.

This is late Saturday/early Sunday morning. This could be interpreted two ways. One, a direct north wind could all but kill the lake effect. Plus, its a pretty swift wind, further limiting boundary-layer moisture. Or two, if this shifts even a little bit, BINGO, there's our northeast wind.

WEEKEND COLD & LAKE EFFECT SNOW

Written by: Brian Neudorff

Based on the comments I have read from Bob's post last night (COLD PATTERN SETTING UP?) I think there has been some miscommunication or a misunderstanding on our forecast for this weekend. A few of the commenters are suggesting we aren't mentioning lake effect for this weekend in our forecast but I know that's not true.

You can even go back to my post yesterday morning (NEW YEARS SNOW, MORE COLD) and I even stated when it looked like the surface storm would back west, "This could produce some decent snow for our region along with some lake effect or even lake enhanced snows across our area. I also can tell you that lake effect snow was in my forecast this morning for the weekend and was in Bob's forecast from last night.

Cold air will arrive across Western New York Friday night into the weekend with the core of the coldest air forecasted to arrive across the region Saturday afternoon (see above graphic from the 12z run of the NAM forecast model at 850mb or 5,000 ft.) This along with a WNW to NW flow and the location of the upper level low means we will see lake effect snow bands that will continue through the weekend and for those who were asking in the previous post, yes this could mean that lake effect could continue into the first part of next week.

At this point being 3 to 4 days out we can't give you any amounts or pinpoint the locations of where the snow bands will set up but the scenario does look like we will get some lake effect snow that lasts through the weekend and possibly into next week as the cold air lingers across the Great Lakes and Northeast.

COLD PATTERN SETTING UP?

Written by: Bob Metcalfe

Stemming of of the earlier post from Brian today, there is improving evidence for a decent east coast storm into the weekend. Again, we'll probably miss out on bulk snow amounts. What I'm looking at is the aftermath of this guy.

This low spins up pretty well. It's a moderately well developed storm. But the pattern in the lower arctic/northern Atlantic may lock the east coast into a fairly long-lasting cold pattern. After all, the coldest air usually sneaks in behind a strong storm.

The data I looked at today indicates that a negative North Atlantic Oscillation pattern is in place, which will lock this storm and the cold air across the northeast well into next week. With that being said, these types of setups typically do NOT allow for major snowfall, rather the "nickel and dime" type of precipitation we've come to "love" this winter so far.