Snowfall totals from historic October storm in the Northeast U.S.

A very early season Nor'easter dumped inches (in some cases feet) of snow across the northeastern U.S. over the weekend.  Dubbed "Snowtober" on social media channels, this historic snowfall affected millions of people throughout the northeast, from the mountains of West Virginia/Virginia through Pennsylvania, New York, and much of New England.

As of Monday morning, there are still over 2 million people without power across the region.  One reason for the rash of power outages is because the heavy wet snow fell on trees that had not lost their leaves yet, creating a great deal of weight, snapping limbs and branches onto power lines.  In addition, the amount of snow was enough to create serious infrastructure issues in many locations.

The map below shows the approximated snow depth as of Sunday morning.  Highest snowfall totals were observed in west and central Massachusetts into southern New Hampshire and Vermont (where elevation was a factor in the totals).  Some of the snow totals were over 20 inches!  One of the many records broken was in New York City, where Central Park recorded it's first 1" October snow in recorded history (which goes back 130 years!).  Hopefully the historically early and heavy snow storm won't portend a rough winter.

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A gorgeous fall weekend expected to end October

As I type, clouds are breaking apart and moving east in the wake of the cold front that moved through Thursday morning and an upper-level system that trailed it overnight last night.  Rain has come to an end, with between 1/4-1/2" across west TN and east AR and 3/4-1" over northwest MS.

North Mississippi received higher rain totals than the rest of the Mid-South Thursday and Thursday night

High pressure will now build in to the region, bringing clear skies and cool temperatures, slightly below normal for late October. With dry air moving in, morning lows will be especially cool this weekend with frost likely for many locations outside the Bluff City as temps fall into the 30s area-wide. There is also a risk of patchy fog tonight, though I believe that risk to be very low in the metro area itself.

A weak, and likely dry, cold front will move through Sunday evening, bringing just an increase in clouds. High pressure will quickly strengthen behind the front and we'll see highs near 70 Monday and Tuesday with full sunshine. By the middle of the week, or next rain-maker arrives. Models are still sketchy on exact timing and impacts from this storm system, but it appears we could see rain chances Wednesday and/or Thursday with highs in the 60s. Slightly cooler weather is expected behind that front.  For complete forecast details, visit the MWN Forecast.

For Halloween activities on Monday, there are no tricks in the forecast! Monday evening will be cool, but clear and dry. Temperatures will fall from the mid 60s at 5pm to the mid 50s by 10pm. Here's to plenty of treats in your goody bag!

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Another mid-week cold front brings rain and cooler weather

Last week, a strong cold front came through, bringing post-frontal rain showers and a blast of cold air that dropped temperatures to their lowest level of the fall and widespread frost outside the city limits. This week, another autumn cold front arrives in a similar fashion. Once again, we'll see scattered showers ahead of the front (very little in the way of thunder is anticipated), post-frontal rain, and falling temperatures. The main difference between the two systems is that I don't anticipate temperatures to drop as low as they did last week.

The first showers should move into the area overnight Wednesday night with the cold front arriving in the wee hours Thursday morning. Wednesday night's low and Thursday's high will both be in the upper 50s with temperatures likely to slowly fall with the rain during the day Thursday, dropping to near 50 by the afternoon rush hour.  By Friday morning, rain will be ending and the low will be in the mid 40s. Clouds depart Friday with highs only in the upper 50s.  Saturday and Sunday mornings will be quite cool, though widespread frost in the suburbs is not expected (though frost is possible in the coldest outlying areas). Rainfall amounts with this system should average about an inch in most locations. See the MWN Forecast for the latest information and what to expect for your ghouls and goblins on trick-or-treat night!

This weather system will also be responsible for the first good snowfall of the season for much of the interior Northeast U.S. and New England, following on the heels of the first snow (some of it heavy) for the central Rockies and Front Range, including Denver and Colorado Springs, on Wednesday.

NOAA's forecast map for Thursday, indicating the passage of a cold front and widespread areas of rain with thunderstorms over the south-central U.S. and the first  fall snow in New England

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Rare Aurora Borealis (Northern Lights) visible over parts of the Mid-South

Parts of the region have the pleasure of experiencing a very rare Aurora Borealis, or Northern Lights, this evening.  We have seen reports from northeast AR, west and middle TN, northeast MS, north AL, NC, VA, and many places in the northeast U.S.

This particular aurora event was caused, according to SpaceWeather.com, by a coronal mass ejection (CME) that occurred around 1pm CDT today [10-24-11] and hit the Earth's magnetic field. The website states that "according to analysts at the Goddard Space Weather Lab, the impact caused a strong compression of Earth's magnetic field" and subsequent geomagnetic storm.  A CME (often associated with a solar flare) is an explosion on the Sun that happens when energy is suddenly released, producing a burst of radiation. Strong flares can reach the Earth's magnetic field, like the one today.  There is plenty of additional information for science "geeks" (like me!) at SpaceWeather.com and on Wikipedia (including animations and video).

It is very rare to see the Northern Lights this far south and red auroras are somewhat rare as well.  The red color is not completely understood, but scientists believe that they occur much higher above the Earth than typical geomagnetic storms (300-500km) and sometimes occur during intense geomagnetic storms. [More technical details on red auroras can be found here.]  The picture below was taken by Jay Malone in Corning, AR on Monday evening. Enjoy!

Photo of Aurora Borealis over Corning, AR on 10/24/11, courtesy Jay Malone

Did you see the aurora?  Let us know below, or send any pictures to photos@memphisweather.net.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Cold pattern brings good chance of frost next few mornings

The strong cold front that has been well advertised the last several days made its arrival on Tuesday morning, and its effects did not disappoint! Along with a day of showers, that brought mostly light rainfall amounts, by far the biggest change behind it was the dramatic drop in temperatures. After a near-record high of 86 degrees on both Sunday and Monday, readings plummeted into the 40s by Tuesday afternoon, a near 40-degree drop! With gusty north winds, for the first time of the fall season, wind chill values were being calculated across the Mid-South! Temperatures have remained quite cool for Wednesday, as we've struggled to climb into the 50s with clouds that have moved in behind the low pressure area associated with Tuesday’s cold front. These clouds will begin clearing tonight, as high pressure moves closer to the region, and this will make for a few even colder nights to come, including the good chance of some frost for parts of the metro.

Once clouds clear this evening, temperatures should fall rather steadily overnight across the area. While the center city of Memphis will likely hover closer to 40 degrees, the suburbs and outlying areas will see temperatures dip into the upper 30s. While some patchy frost is a possibility for the coldest areas and in sheltered locations, wind speeds of 5-10mph will likely preclude the development of widespread frost.

A much better chance of frost appears to be setting up for Thursday night into Friday morning, as high pressure moves overhead. This will allow for winds to become light to calm, and with clear skies, optimal radiational cooling is expected. Minimum temperatures in the mid to upper 30s are expected, and areas of frost are quite likely for much of the metro by Friday morning, with perhaps just the city limits of Memphis warm enough to prevent much frost from forming.

NWS surface weather map forecast for Friday morning, showing the Canadian high pressure area directly over the region, which will enhance the chance of frost formation for much of the metro area.

A final, lesser chance of frost may occur Friday night into Saturday morning. Temperatures will be a bit milder as southerly wind flow begins to return, but winds may be light enough, along with continued clear skies, to allow a few readings in the upper 30s in the outlying areas that could promote some additional patchy frost in these areas.

If you have sensitive plants, it may be a good idea to cover or bring them indoors the next few nights to prevent damage. After Saturday morning, the threat of frost will be ending, for at least a little while. The weather pattern will be moderating under the returning southerly wind flow, with temperatures back to average levels, if not a bit above, by early next week. However, another front may bring rain chances for the middle of the week, and some long-range models are indicating another blast of cold air could follow. We’ll be tracking that possibility closely next week!

Stay tuned to MemphisWeather.Net for the latest on the possibility of frost, including any formal frost advisories that may later be issued by the National Weather Service office in Memphis.

--Kevin Terry, MemphisWeather.Net

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Early week front will bring rain, then a major cool-down!

After our first rainfall in 16 days occurred this past Wednesday, the weather pattern over the Mid-South has returned to the dry and mild regime we’ve seen much of the last couple of weeks. However, a significant pattern change will be evolving over the region and much of the nation in the next few days thanks to a powerful cold front that is currently located in the Central Plains. This front will move through our region late Monday night and Tuesday morning first bringing rainfall, and then a sharply cooler air mass that may lead to the first widespread frost of the Fall season!

In advance of the approaching front, southerly winds that have returned today have brought very warm and breezy conditions to the area. Temperatures have been very close to record highs, in the mid to upper 80s, and this will likely repeat on Monday afternoon just before the front’s arrival. These warm temperatures will be a distant memory though by the middle of the week.

The cold front will begin to enter the region Monday night, and rainfall is expected to have developed along and behind the front. Rain should be entering the metro area during the overnight, and will continue into Tuesday morning, meaning you should expect a wet commute for your morning rush hour. A few thunderstorms will also be possible, but because most precipitation is expected to be behind the front, rather than ahead, in much more stable air, thunderstorm coverage is not expected to be widespread and severe weather is not anticipated. Most rainfall will be moving out by mid-morning Tuesday. Rainfall amounts up to a half inch, locally higher, will be possible.

NWS total precipitation for late Monday night into Tuesday morning, showing rainfall amounts between 1/4" and 1/2” over the metro area. Locally higher amounts will also be possible.

The biggest and most immediate change in the wake of the passing front will be falling temperatures. Readings will quickly fall into the 50s by Tuesday morning, with gusty northwest winds, and will recover little during the day. Strong, large, and Canadian high pressure will be building in behind the front, feeding even cooler and drier air into the region Tuesday night into Wednesday. By Wednesday morning, readings will be in the lower 40s, and it appears temperatures may not climb out of the 50s on Wednesday afternoon!

The coldest temperatures are expected Thursday and Friday mornings as high pressure makes it closest approach to the region, leading to clear skies and light winds. It appears increasingly likely that the region will see readings dip into the 30s, at least in the Memphis suburbs and outlying areas, and this could lead to the first widespread frost of the fall season. Jackets, blankets and other cold weather gear will likely be in use by many Mid-Southerners during this time! Temperatures are only expected to slowly moderate as we head into next weekend, with highs returning to the lower 70s, but lows remaining cool - in the 40s.

GFS model forecast temperatures Friday morning, showing readings possibly in the 30s, which may lead to a widespread frost.

Stay tuned to MemphisWeather.Net during the week for the latest details on Monday’s cold front and the coming week’s much cooler temperatures, including the possibility of a frost!

--Kevin Terry, MemphisWeather.Net
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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Autumn cold blast due by the middle of next week!

As I was looking over the mid-range model data today, I saw reinforcing evidence of something I had been watching for a couple of days.  In fact, when I saw it, I tweeted about it. Models are consistent in predicting a major blast of fall weather next week!

The map below shows the GFS model forecast for Tuesday morning. (You'll probably want to click it to enlarge it even further.)  The color fill is precipitation for the early morning hours Tuesday - rain and possibly a few thunderstorms could affect the region early in the day. A strong cold front is depicted as a blue dashed line that would arrive in the Mid-South early in the day.  Be sure to take note of the direction of the wind behind the front and the source region for that wind (I've provided an assist with the big blue arrow).  Massive high pressure, with Canadian origin, is building in behind the front.  As large as the high is, it will dominate the weather for several days.  Also take note of the temperatures behind the front. Readings in the 30s are found dropping as far south as Kansas Tuesday morning with 40s across northwest AR.

In a nutshell, we are due to see some of the coldest temperatures yet this fall by Wednesday and Thursday mornings next week as that massive high pressure system inches closer. Readings in the 40s will be common and I wouldn't be surprised to see some frost in outlying areas those mornings.  In the meantime, I have posted highs in the mid 60s for mid-late next week, but don't be surprised if those numbers are adjusted down by then.  We could have trouble getting out of the 50s on Wednesday and Thursday!

How about you? Do you enjoy this kind of weather or is mid-October too early for talk of lows in the 30s?

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Best chance for rain in some time arrives mid-week

It’s been a fantastic run of weather for the past couple of weeks, where even clouds have been tough to find on most days! With few to no clouds, rain has not been a concern either. In fact, the last measurable rainfall most of the Mid-South saw was on September 25. So, many areas are likely in need of a bit of precipitation by now, and though a few sprinkles have been around today, the vast majority of the area has stayed dry. Later in the week will provide the opportunity for more of the region to see some rainfall.

Once the increased clouds and very isolated sprinkles move out this evening, conditions will return to the rule of the past several days through Tuesday night with partly cloudy skies and temperatures a bit above the early October average, in the lower 60s for lows and lower 80s for highs. Meanwhile, a cold front will be moving out of the Central Plains and towards the Mid-South on Wednesday, bringing the chances for rain. At this time, it appears an area of scattered showers, and possibly some thunderstorms as well, will move through the region Wednesday afternoon into the evening, just ahead of the front. While not all areas may end up seeing rainfall, it will certainly be the best chances since the cold front of September 25. An isolated stronger storm cannot be ruled out, but atmospheric conditions do not appear to be lining up for organized severe storms or particularly heavy rainfall amounts.

NWS Total Precipitation for Wednesday evening, showing light rainfall amounts (up to 1/4”) possible across the region in association with a passing cold front

The front will clear the region by Thursday morning, bringing a return to dry weather for the remainder of the week into the weekend. Somewhat cooler temperatures will follow as well, but since this front will not be Canadian in origin, but rather based out of the Pacific, it will mostly act as a humidity reducer. High temperatures will manage to drop back to the mid to upper 70s to close out the week, before returning to near 80 for the weekend, while overnight lows return to the 50s.

--Kevin Terry, MemphisWeather.net

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Omega block continues to bring pleasant fall weather to the Mid-South

Looking at the upper level weather maps this morning, the pattern that has controlled our weather for the past several days is still in firm control of our weather.  The upper level pattern we are under the influence of is termed an omega block. The term comes from the fact that the pattern represents the Greek letter omega (picture at left). An omega block is characterized by three pressure systems - low, high, low (from west to east).  The pattern also tends to be very stagnant, due to the strength of the high pressure system, resulting in days to weeks of the same weather over an area. The Mid-South has fortunately been under the high pressure portion of the block, resulting in an extended period of dry and sunny weather.

An omega block resides over the continental U.S. with low pressure on the coasts and high pressure dominating the central U.S. The omega block gets its name from the contouring of the upper-level pressure systems, which resemble the Greek letter omega. This map shows the 500mb layer (about 18,000 feet).

As the week progresses, the omega pattern will slowly shift east and weaken by the end of the weekend, allowing a more progressive pattern to return, meaning fronts will make steadier progress across the United States as we head into the middle of October.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

Major hurricane Ophelia's effects recorded by NOAA buoy

On Saturday morning, October 1, as it reached category 3 strength, Hurricane Ophelia passed directly over a NOAA buoy positioned  a couple hundred miles south-southeast of Bermuda in the Atlantic Ocean.  The position of buoy 41049 is shown in the map below.

As you can see from the map, there is a network of buoys within about 50 miles of the U.S. coastline and a series of buoys much further offshore (buoys are shown as yellow and red diamonds). While it is not unusual for a landfalling tropical system to pass over a near-shore buoy, it takes pretty good aim (or a fair amount of luck) for a storm to pass directly over a buoy in the middle of the ocean!

The usefulness of these buoys is magnified when a tropical system gets close enough to one of these floating instrument platforms (see the pic of a buoy similar to 41049 below). The meteorological data that can be gathered as the storm passes aids the National Hurricane Center in forecasting the strength, movement, and other attributes (such as wind field and wave heights) of a storm through direct measurement, rather than remotely using satellite data.

In this case, the graphs below show what the wind, air pressure, and wave heights were as the storm passed overhead.  In the first graph, the air pressure (green) plummeted to about 28.10" in the eye of the storm, the wind speed (blue) reached nearly 70 knots (80 mph) and gusted to 100 knots (115 mph)!  In the second graph, the wave height reached just over 40 feet in that 100+ mph wind!  In this case, the buoy data affirmed the strength that the Hurricane Center had indicated for the storm at that time.

And finally, here is the satellite imagery for approximately the same time as Ophelia traversed buoy 41049.

Most Atlantic tropical systems are tracked on the MWN Tropical page.  Check it out whenever there are storms that pose any threat to the U.S. or other land masses.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

September 2011 Climate Data and MWN Forecast Accuracy

With one of the hottest summers on record in Memphis in the history books (3rd warmest behind 1980 and 2010), a welcome change arrived in September - temperatures averaged below normal for the month! After temperatures of 96 or higher the 1st through 3rd, fall arrived with only two 90+ degree readings the rest of the month. Precipitation was also slightly below average. No daily records were broken during the month.

Memphis International Airport, Memphis, TN

The average temperature for the month of September was 73.3 degrees, which was 1.9 degrees below normal and over 10 degrees cooler than August. The average high temperature was 83.6 degrees and the average low was a pleasant 62.9. The coolest temperature of the month was 55 degrees on the 7th and again on the 27th, while the highest temperature was 99 degrees on the 1st.  There were just 5 days in which the high temperature reached at least 90.

Precipitation for the month totaled 2.56", which was 0.53" below average.  There were just 5 days with measurable rainfall and most of that fell on 2 days that measured more than one inch each (the 19th and 25th). The greatest 24-hour total was 1.32" on the 25th. The peak wind gust was 39 mph on the 14th with an average wind speed for the month of 6.8 mph. Click here for a daily statistical recap for Memphis International Airport.

Cirrus Weather Solutions, Bartlett, TN

The average September temperature at Cirrus Weather Solutions in north Bartlett was 69.9 degrees with a maximum of 99.2 degrees on the 1st and a minimum of 48.2 degrees on the 9th. September precipitation was about an inch more than the Memphis airport, totaling 3.50". A co-located manual gauge used for the CoCoRaHS program measured 3.70". The peak wind gust was 28 mph on the 5th. Average relative humidity was 70%. Click here for a daily recap on MemphisWeather.net.

MWN Forecast Accuracy

For the month of September, the average temperature error in all MWN temperature forecasts was 2.22 degrees, lower than all compared computer models, including the NWS. Nearly 65% of the MWN temperature forecasts for the month were within 2 degrees of the actual temperature. MWN's forecasts extend out five periods (or 2.5 days). For dewpoint accuracy, the MWN forecast beat all data sources, averaging 2.42 degrees error and falling within 2 degrees of the actual dewpoint 62% of the time. Historical accuracy statistics can be found here.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.