We’ve been sweltering for weeks now in the heat and humidity of summer, but it really wasn’t all that long ago we were dealing with a cool spring that was preceded by a long and grueling winter that featured the 6th highest snowfall amount ever measured in Rochester (68 inches.)  The extreme cold and excessive snow of last winter were primarily a result of what we call a La Nina pattern where the ocean temperatures in the central Pacific are colder than normal, changing the weather patterns of the northerrn hemisphere.  Typically, La Nina patterns mean wetter than normal weather for the western Pacific while the colder ocean water in the central and eastern Pacific keep the southern United States dry and cool while the Midwest will be cold and oftentimes snowy.  It’s hard to believe it’s been a year now since I sat here writing about the Climate Prediction Center’s La Nina outlook for last winter that also carried over into spring.  The latest Climate Prediction Center’s outlook is indicating that we may be facing another cold winter this year and in fact Thursday they issued a La Nina Watch for this upcoming winter!  While the likelihood of such a strong La Nina event being repeated is low, there are signs that this winter may at least feature weak La Nina tendencies.  Does this mean we’ll have another snowy winter?  Not necessarily.  Only about half of all La Nina winters feature more than the normal amount of snow, but pretty much all of them bring colder than normal conditions to our area.  On the link below, there’s a chart that shows the sea surface temperature of the central Pacific over the past winter through this summer with predicted temperatures on the right hand side looking ahead to the winter and beyond.  Notice that water temperatures were cold duing the La Nina of the winter and spring before climbing to normal levels for our hot summer and then appear to fall off in the future for the upcoming winter.  The La Nina conditions likely won’t assert themselves until the early part of winter while fall itself looks to be normal for us, possibly even a little warmer than normal early on.  The bottom line here is it’s early and things may change a bit, but the odds now appear that we may need to have the snow shovels at the ready and the snowmobiles gassed up when winter roles around…just in case!

Posted under winter

Well it goes without saying that we’ve had our share of snow so far this winter.  To date, Rochester has officially received 59.5″ of snowfall, the most we’ve measured in several years…and it’s not even March yet!  In fact, we may be getting a few more inches before we get to next month as this “active” weather pattern continues to provide us with snow chances for the next few days.  Right now, it looks like we may get some flurries or very light snow showers in southern Minnesota this afternoon and tonight while north Iowa may be in line for an inch or two by sunrise tomorrow, especially south of Decorah and Charles City as one big storm system grazes us to the south.  Another little storm system will bring light snow chances for tomorrow and Saturday with an inch or two for most of us expected between late Friday night and Saturday evening.  The biggest storm on our horizon will brush past us on Sunday afternoon and Sunday night.  Tha latest data suggests that we may be getting a few inches of snow and sleet late Sunday…and possibly a little freezing rain during the afternoon.  Beyond this weekend, the National Climate Prediction Center’s forecast for March is calling for near normal precipitation, but colder than normal temperatures as our La Nina pattern persists.  Incidentally, the cool stuff may be sticking around through May, making for a potentially chilly spring, but things look to return to normal for the summer.  This isn’t to say we’ll be getting a huge dumping of snow this March, but even if we get just the average 9 inches of snowfall during the month, we may find ourselves in the top ten or even top five list of all-time snowiest winters in Rochester history.  From the looks of things in the next two weeks, this current “active” weather pattern will continue leading to frequent chances of snow or rain…if the models verify that is.  Stay tuned (and keep the shovels handy just in case.)

With a little snow possible this weekend and a potentially "active" March ahead, we may find ourselves in the top 5 of the snowiest winters.

Posted under winter weather

The National Oceanic and Atmospheric Administration (NOAA) has released its latest update for this year’s hurricane outlook and things still look to be quite active in the Atlantic basin in the next few months.  Of more interest to us locally is the mention of a possible “La Nina” impact on the hurricane outlook.  If La Nina does become more pronounced in the next few months, not only will there be less vertical wind shear in the tropics to encourage hurricane development, but our upcoming winter here in the Midwest is certainly going to be affected.  In the latest Climate Prediction Center analysis there was some evidence that suggests we may be dealing with a moderate to strong La Nina phase this fall and winter which could mean a warm fall followed by colder than normal temperatures over the winter months.  It’s too early right now to make snowfall predictions, but it seems very possible that we could be facing a snowier period from December through March if the Climate Prediction Center’s long range forecast pans out, so you may want to wax up your skis and tune up the snow blower…just in case.  Below are the latest NOAA hurricane outlook statement and the preliminary outlook for this upcoming winter from the Climate Prediction Center.

NOAA Still Expects Active Atlantic Hurricane Season; La Niña Develops

The Atlantic Basin remains on track for an active hurricane season, according to the scheduled seasonal outlook update issued today by NOAA’s Climate Prediction Center, a division of the National Weather Service. With the season’s peak just around the corner – late August through October – the need for preparedness plans is essential.

NOAA also announced today that, as predicted last spring, La Niña has formed in the tropical Pacific Ocean. This favors lower wind shear over the Atlantic Basin, allowing storm clouds to grow and organize. Other climate factors pointing to an active hurricane season are warmer-than-average water in the tropical Atlantic and Caribbean, and the tropical multi-decadal signal, which since 1995 has brought favorable ocean and atmospheric conditions in unison, leading to more active seasons.

 “August heralds the start of the most active phase of the Atlantic hurricane season and with the meteorological factors in place, now is the time for everyone living in hurricane prone areas to be prepared,” said Jane Lubchenco, Ph.D., under secretary of commerce for oceans and atmosphere and NOAA administrator.

Across the entire Atlantic Basin for the whole season – June 1 to November 30 – NOAA’s updated outlook is projecting, with a 70 percent probability, a total of (including Alex, Bonnie and Colin):

• 14 to 20 named storms (top winds of 39 mph or higher), including:
•  8 to 12 hurricanes (top winds of 74 mph or higher), of which:
•  4 to 6 could be major hurricanes (Category 3, 4 or 5; winds of at least 111 mph)

These ranges are still indicative of an active season, compared to the average of 11 named storms, six hurricanes and two major hurricanes; however, the upper bounds of the ranges have been lowered from the initial outlook in late May, which reflected the possibility of even more early season activity.

“All indications are for considerable activity during the next several months,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center. “As we’ve seen in past years, storms can come on quickly during the peak months of the season. There remains a high likelihood that the season could be very active, with the potential of being one of the more active on record.”

Winter Outlook:

Climate Prediction Center temperature probabilities for this winter

Climate Prediction Center precipitation probabilities for this winter

Posted under Tropical weather, winter