Last Updated: 1/31/15 8:00 AM (Samantha Roberts)
Last Updated: 1/31/15 8:00 AM (Samantha Roberts)
From Meteorologist Samantha Roberts
I've been doing a lot of thinking about this lately. ...this thing where sometimes our forecast is wrong.
I'll admit that when a forecast doesn't pan out, it bothers me. I know that many of you, especially those who work outside, plan your day around what we tell you. I hate to be part of the reason you cancelled your outdoor party, or part of the reason you decided to lay cement on a different day than originally planned.
So, why are we (meteorologists) wrong sometimes? Let's use a recent example. Remember the big storm that brought us snow earlier this week? It also brought our friends in the northeast and New England snow. A LOT of snow. In fact, in New York City, they pretty much shut most of the city down and made A LOT of adjustments because of a forecast for FEET of snow in the city. Sure they got snow in New York City proper but not as much snow as some expected.
"HOW could a forecast be so wrong," people exclaimed?
I think there can be many reasons that a forecast doesn't pan out as expected. Our friends at the National Weather Service in Kansas City put together an awesome graphic that illustrates some of the reasons forecasts don't pan out.
I hope that you won't take this post as a "cop out," or me making excuses for the forecast being wrong sometimes. Weather forecasting is easy on some days, and other times, it's tough. It all depends on the weather set-up.
We use forecast models to develop an accurate forecast, but it's important to note that we also use our own knowledge of the local area and our past experience with various weather set-ups to make a forecast for you. For instance, models don't always pick up on "the dreaded wedge." Luckily, our own Jim Duncan is great at sniffing out the wedge because he's lived here for many years and knows the signs. Each member of our team brings forth unique experiences that help make these forecasts more accurate.
I also know that there is a 100% chance that we will use all of the tools at our fingertips to bring you the most accurate forecast possible.
From Meteorologist Samantha Roberts (1/28/15 6:30 AM)
While we're waking up to clear skies and (mostly) melted snow, our friends in the Northeast and New England are really digging out this morning. ...especially those in New England.
You may have heard that the forecast snowfall totals for New York City didn't pan out as many had anticipated, but in Boston?! New England?! Pass the shovel, please!
The following map illustrates storm total snowfall over a 24 hour period ending this morning. Areas highlighted in gray received the highest amounts of snow...30" PLUS!
Some of the big winners for you were:
Littleton, MA: 34.0"
Framingham, MA: 33.5"
Thompson, CT: 33.5"
Methuen, MA: 31.2"
Can you imagine?
A little bit closer to home, the numbers were much less...impactful, if you will.
Portions of Chesterfield, Henrico, and King William counties were the local winners.
Midlothian (Chesterfield co.): 2.0"
Brandermill (Chesterfield co.): 2.0"
Bon Air (Chesterfield co.): 2.0"
Short Pump (Henrico co.): 2.0"
Aylett (King William co.): 2.0"
So, all of my aspiring Snowcasters Of The Year...we should have a winner by now, right? No! (Unfortunately?), we only accumulated 0.01" at Richmond International Airport. In order to be crowned the NBC12 Snowcaster Of The Year, you must guess the correct date of the FIRST inch of snowfall at the airport. We haven't had that yet!
...and it doesn't look like we'll have a winner anytime soon. (At least, for the next seven days...)
How many of you woke up this morning....looked out your window....and your jaw dropped when you saw the Winter Wonderland? This happened to me this morning as I woke up at my house in the West End of Henrico County. Can I honestly say I was expecting it to snow that much overnight? NO!
So what happened? Well first, let's keep in mind that NOT EVERYONE in Central Virginia saw that blanket of white on the ground that I witnessed (about 2" of snow). Snowfall amounts ranged considerably from just a trace up to 2". There were plenty of locations, however, that saw at least 1" of snow.
This was never an easy forecast from the get go. It started off as a "Clipper System"...(you often hear us talking about these in the winter months)...a quick moving area of low pressure that was approaching Virginia from the west. Typically, these types of storms don't bring us very much in the way of moisture. The mountains to our west get in the way, and we end up seeing light precipitation by the time it reaches us in central Virginia. If it's cold enough, we can get some light snow. This go around, it was warm enough that we saw light rain on Monday with temperatures well into the 40s to around 50°. This part of the forecast worked out well, as we expected.
The energy from this "clipper" then transferred off the coast and that's when the powerful 'Noreaster began to take shape. Our computer models had hinted for days that we could end up seeing a band of snow developing in central or eastern Virginia last night as this low moved away towards New England. The tough question to answer...where exactly was that band going to set up and how much snow would it produce??
We tracked that band of snow showers for you Monday evening once it developed. They were quickly diminishing over much of Central Virginia before midnight. Snowfall accumulations appeared to be on target with only minor accumulations being reported. The Northern Neck and areas in Northern Virginia were seeing a bit more, as we had told you to expect.
What happened overnight into Tuesday morning is what was UNEXPECTED. The huge circulation around that intensifying 'Noreaster (keep in mind, WAY OFFSHORE) actually kept that band of snow going near the Northern Neck, and it even expanded back to the west closer to the I-95 corridor.
In the image below, notice the radar image from 9AM this morning. A long, but narrow band of snow was falling from western New York State all the way south into central and eastern Virginia. Notice that the main batch of snow was much closer to the storm center itself....at this point in time, the low was more than 500 miles away from us!! AMAZING!
Computer models had not given us any indication that this would happen overnight...in fact, they showed the opposite....a drying trend, especially for communities closer to Richmond.
In our experience, it is a rarity to see a narrow snow band like this develop and persist when it is so far away from the main storm center. It did weaken steadily through the day, but was still producing some snow showers and flurries into Tuesday evening.
Forecasting the weather is a complex and humbling experience. Whether we like or not as weather forecasters, there have always been and always will be "SURPRISES" such as what occurred this morning. For some of you, it was a very pleasant surprise considering the snow drought we have been in so far this winter. For others, it was definitely an inconvenience. Those of you who were traveling Tuesday morning, hopefully you made it to your destination safely!!
On behalf of the entire First Warning Weather Team, we thank you for watching.
Meteorologist Ros Runner
Posted by Andrew Freiden 1/13/2015
Here's a link to a story by my buddy Walter Griggs. It chronicles life in Richmond on the day it snowed almost 2 feet! It's a record that has stood for 75 years!
Records are made to be broken, right?
I sent out this tweet earlier this morning:
What's freezing fog? Super tiny liquid water droplets, suspended in sub-freezing air. When they hit something, it freezes into a glaze— Andrew Freiden (@AndrewNBC12) January 22, 2015
You know how the freezing point of water is 32°F? Actually, that's not really the case. That's the freezing point of flat water. When the water is in tiny droplets, like the ones in fog, it's hard for them to arrange themselves into a crystalline form. So they can stay liquid, even when temperatures are well below freezing.
Does this blow your mind? It blew mine the first time I learned about it!
When the freezing fog hits a surface, it flattens out. This flat water instantly freezes, and any surfaces that are in the freezing fog get a thin coating of ice.
NASA released its yearly review of global temperatures today and as a whole, it was the warmest year since records began in 1880. This beat the previous record warmest years of 2010 and 2005. 2014 marks the 38th consecutive year that the yearly global temperature was above average and 9 of the 10 warmest years on the record book have now occurred since 2000.
That said, it was not the warmest year on record for everyone. The image below shows how much warmer or cooler than average it was across the planet.
As you can see, while many areas show up in red, the eastern U.S. is one of the few spots that saw below average temperatures. This was due in large part to the extremely cold winter we saw last year. It was the 33rd coldest winter on record for the U.S. and was the coldest winter many areas in the eastern U.S. had seen since the 1970s.
In Richmond, we experienced a very cold winter in 2014 as well. According to the National Weather Service, there were 7 days with a high temperature below 32 degrees; 2.5 days above average. However, it was a slightly warmer than average summer. There were 45 days with a high of 90 degrees or higher; 3 days above average. This resulted in our overall temperatures being very close to average. Our average temperature was 58.8 degrees; just 0.1 degrees below average.
This is why the "global" part of the term global warming is very important. In a given year, not everyone will experience warmer than usual conditions. Regional weather is much more variable than the overall global climate. There can still be extended periods of cold weather and record breaking lows can still be set. But when you look at the big picture over long time periods, it is impossible to deny that Earth is gradually warming.
How much of this warming is due to natural phenomena and how much of it is caused by human activity? This is where the debate about global warming now rages in the scientific community and where more research is needed. Whatever the cause, we won't notice any dramatic changes in our weather any time soon, but a warmer climate could have major impacts on future generations. The better we can understand why this warming is occurring the more prepared we will be for the future.
Posted By Meteorologist Matt Holiner, 1/16/15 at 6pm
We're halfway there!
Today, January 15th, marks the midway point of meteorological winter. You may be thinking that spring begins on March 20th, but for meteorologists it begins on March 1.
Meteorological winter, which runs from December 1st-February 28th, comprises our three coldest months. Astronomical winter starts and ends a little later as it is tied to our shortest day of the year (December 21st or 22nd) and the day where we have equal amounts of light and darkness (March 20th or 21st).
Since we're at the midpoint, I decided to look back and review what this winter has been like so far. December was warmer than usual for Richmond, but precipitation was about average. There weren't any major arctic balsts and there was no measurable snowfall. Here's an in-depth summary of the month from the National Weather Service office in Wakefield.
December 2014 Summary
-The average temperature at Richmond International Airport was 43.9 degrees, which was 2.9 degrees above normal.
-The average high temperature was 52.9 degrees or 2.2 degrees above normal. The average low temperature was 34.8 degrees or 3.4 degrees above normal.
-The highest temperature was 76 degrees on the 1st. The lowest temperature was 23 degrees on the 31st.
-Precipitation came in at 3.14 inches, which was 0.12 inches below normal.
-The greatest 24 hour total was 1.34 inches from the 23rd into the 24th.
The beginning of January started out pretty warm too. On January 4th, we got all the way up to 70°! Since January 6th though, all of our high temperatures have been below average. Our coldest day so far has been January 8th, when our high was only 26° and our low got all the way down to 12°. Yesterday and this morning marked our first measurable snowfall, right around 1/10 of an inch.
Mid-Janary is typically when we see our coldest temperatures of the year. Our average high in Richmond is 47° while our average low is 28°. Once we get past today though, our average temperatures begin to climb slowly.
What can we expect for the rest of the winter? In the short term, it looks like our temperatures will be about average. Near the end of January, there are hints that we'll get some more significant shots of cold air, potentially setting us up for a cooler than average February. With precipitation expected to be about average, we think we're going to have several more chances for some good snows across Central Virginia. This is a VERY early forecast, but is our best guess for now.
We're still far from winter being over, but it's a warming thought to know that we're halfway to the start of the spring!
Posted by Matt Holiner (1/15/2015) @10:00AM
This is a great picture:
It's from Wintergreen's twitter feed. It shows a bright blue sky ABOVE the clouds. Down closer to sea level, we are BELOW the clouds. With calm winds, it's going to be a struggle to clear the clouds.
We think we'll eventually do it, giving us a few hours of partly sunny skies during the midday/early afternoon. But it won't last long-- more clouds stream in later in the day.
After a week of clouds, some sun would be nice!
-Post by Andrew Freiden (1/15/2015) @ 9:30am