Brush Fire Risk Elevated Early in the Week

While it's been chilly outside, the air mass that is in place is quite dry.  The relative humidity will be between 20 and 30 percent this afternoon across the area.  Combine that with the dry brush and occasional wind gusts as high as 20 MPH, the brush fire threat will be elevated today and again tomorrow.

Even though we had locally heavy rainfall last week and the ground may still be moist in spots, the brush on the ground dried out quickly, which is what burns in a brush fire.

So, while the threat for brush fires is not critical, it is a good idea to postpone any open burning until we get some rain.  It only takes one gust of wind and a spark to start a brush fire.

--Meteorologist Brian Thompson

Why is it colder in March than September?

This is a question that I received not too long ago. I think it is an interesting topic. Hopefully, you enjoy:

"I believe that I understand the concept that the sun is the cause of the seasons, and how longer days cause our summers. You often mention about how strong the sun is and that the sun is as strong in March as it is in September, but that doesn’t quite make sense to me. If the sun is strong enough to cause the average temperatures to rise in March, then how is it weak enough for the averages to drop in September?"

I applaud questions like this because it means that the things I say are inspiring complex thought. You are correct that the sun is the cause of the seasons, but it is not just simply the amount of sunlight that causes the seasons. If you think about it, the North Pole gets a lot more hours sunshine in the summer than Miami does. Why is it then warmer with less sun in Florida? It has to do with the angle of the incoming energy from the sun. The sun is much higher in the sky over tropical areas, and when the sun is higher in the sky, two things happen to allow it to better heat the ground. The first is that the sun is more concentrated when it strikes the ground. You can experiment with a flashlight in a dark room to see how this works. A flashlight pointing straight at the wall will have a brighter and tighter spot, but a beam that is more angled will have a fainter and more spread out lit area. The second thing that happens to a lower sun is the fact that the sunlight must pass through a larger slice of the atmosphere. The air molecules then scatter the energy in all directions and less actually makes it to the ground.

But I have avoided the true answer to why March and September differ. The best way to answer this question is to review the processes of heating and cooling. At all times there is a two way process to cause a change in temperature. It is easy to comprehend the fact that when we add heat energy to an object, its temperature rises. Though what many people don’t realize is that all objects that have a temperature are constantly radiating energy away from that object. The amount of energy being radiated, or lost, from an object is dependent on the temperature of an object. For that object to warm, it must gain more energy than it losses through this radiation. To better explain, let’s use an example of two bricks; one brick is at a temperature of 50 degrees and the other at 90 degrees. Because the second brick is hotter, it is radiating energy at a faster rate than the cooler one. Therefore, if we wanted to warm each brick an additional 5 degrees, the hotter brick needs more energy to make this happen than the cooler one.

If we understand the example of the bricks, we can then apply this to the question at hand. In March, our part of the planet is colder than it is in September. Therefore, the ground needs less energy to warm in March than it would in September. While the same energy coming in from the sun is enough to cause the temperature to rise in March, we are still losing more than we gain in September. The resultant is the cause of the rising average temperatures in March while averages fall in September. This answer also stresses how hard it is to get extreme heat. When temperatures reach into the 100s, it requires a tremendous amount of energy to get even a little more rise.

Finally, Some Time to Dry Out

The last two to three weeks have been quite active across Central Pennsylvania as we have found ourselves under several Flood Watches and Flood Warnings because of the threat for heavy rain.  At times, there have been some quick dumps of snow and ice to remind us that it is still winter, too.

The problem over the last two weeks has been the constant snowmelt combined with a moderate to heavy rainfall every couple of days.  The frequent rainfall certainly doesn't help the situation, but it was the constant melting snow that really helped keep the rivers, streams and creeks high over the past couple of weeks.  This past week, we saw some heavy amounts of rain on Sunday followed by heavy amounts for snow for some Sunday night.  After the sun came out for a couple of days, the snow melted pretty quickly, which helped keep the streams and creeks high.  Then, we tossed 1 to 3 inches of rain on a fairly saturated ground Wednesday and Thursday, which led to the flooding that we saw.

The good news is that we have finally broken that cycle of a couple of dry days followed by a rain or snow event.  We will see some rounds of light showers and light rain this week, but the rain totals by the end of this coming week will be a drop in the bucket compared to what we had last week.  And since there is very little snow on the ground, the break from the heavy rains will finally allow those rivers, streams and creeks to return to their banks.

--Meteorologist Brian Thompson

"What Happened to 'A Coating to an Inch'"

I'm sure many of you were asking that as the snow kept falling...and falling...and falling yesterday into last night.  I went on-air Saturday night forecasting nothing more than a coating to an inch for the deeper valleys to the south and east, including State College and Huntingdon.  Low and behold, I sit here typing 36 hours later and those areas are digging out from 6 to 10 inches of snow.  Farther west, the forecast held up relatively well, while those spots farther east in the "inch or less" area got rocked.  So, what went wrong?

The whole forecast was like walking on a tightrope.  A cold front was going to come through on Sunday, which would bring enough cold air to change the rain over to snow -- that was a given.  But, a potent storm was going to move along the fierce battle zone that was that front.  You know how we always talk about how the track of the storm means everything?  Forecasting Saturday night, I expected the storm to track over Harrisburg, with the front making enough progress to bring accumulating snow (3-6") to Elk, Cameron and Jefferson counties, but for most areas the cold air would arrive too late and the precipitation would already be over. 

So, the low didn't track over Harrisburg, but instead about 100 miles to the east in Philadelphia.  The cold air rushed into the entire area earlier in the afternoon and the storm took a track that is perfect for heavy snow in the eastern part of our area.  Bands of snow set up in these areas and just kept constantly dumping snow.

This also adds another forecasting headache for later this week - the threat for more flooding.  The melting snow will give the area rivers, streams and creeks high all week.  Add the chance for locally heavy rain Thursday and we may find ourselves bracing for flooding again.

So here are some of the snowfall totals you have sent in.  Thanks to everyone who did send them in, and thank you all for keeping the snide comments to a minimum.

PA Furnace (Huntingdon) 11"
Stormstown (Centre) 10"
Philipsburg (Centre) 9.5"
Spring Mills (Centre) 9"
State College (Centre) 9"
Beech Creek (Clinton) 8"
Todd (Huntingdon) 7"
McConnellstown (Huntingdon)  7"
Skelp (Blair) 6"
Three Springs (Huntingdon)  3.5"
Everett (Bedford) 2.6"

--Meteorologist Brian Thompson

It's Severe Weather Awareness Week

This week is Severe Weather Awareness Week in the state of Pennsylvania.  I'll start off talking about severe thunderstorms and tornadoes today, and we'll talk about flooding later on this week.  It was kind of ironic that we kicked the week off with some thunderstorms Monday morning, but we didn't see any severe weather.  However, it will not be very long before we start to see severe thunderstorms as warmer air tries to march its way northward.  The prime severe weather season in Pennsylvania is between April and July, with the most tornadoes occurring between May and July.

To be classified as a severe thunderstorm, a storm must do one or more of the following:

• Produce a wind gust of 58 MPH or greater

• Produce hail of 1" diameter or greater

• Spawn a tornado

While Pennsylvania is not as prone to severe weather as the plain states, but there were still 508 reports of severe weather in Pennsylvania last year, including 15 tornadoes.  Those tornadoes were mainly in eastern parts of the state as well as right along the NY/PA border. 

There were no confirmed tornadoes in our viewing area last year, which is not all that out of the ordinary.  That being said, it is important to remember that even though tornadoes in this area are relatively rare, they can happen.  In the famous May 31, 1985 outbreak, our area was home to an extremely impressive tornado that tracked 69 miles across the Moshannon and Sproul State Forests, with the width of the damage exceeding two miles in spots.  It is rare for a tornado to stay on the ground for more than a couple of miles, so for a tornado to continue for 69 miles is remarkable.  This particular tornado traversed high elevations and mountains, which brings me to a common myth about tornadoes that I hear all the time -- that they can't form here because of the mountains.  They can, and do form over mountainous areas.

Below is the number of tornadoes in recorded history broken down by county:

What can you to protect you and your family from severe weather?  Keep up to date on the latest watches and warnings, especially if you plan to spend time outside.  The best way to get immediate information on watches and warnings is to purchase a NOAA Weather Radio.  We have teamed up with Alert Works to get you a great deal and FREE shipping on a NOAA Weather Radio -- you can check that out here: http://wearecentralpa.com/weather/weather-radio 

When your area is under a Severe Thunderstorm Watch or a Tornado Watch, that means that severe weather and/or tornadoes are possible in your area over the next several hours.  If you plan to be outside, keep your eyes and ears open for rapidly changing weather conditions.  If you hear thunder, you are close enough to the storm to be struck by lightning.  Move into a car or inside to a sturdy building away from windows.  Do not seek shelter under trees.  If you find yourself out in the open with no place to go, crouch down as low as you can so that you are not the tallest object.  If you are indoors, stay away from windows and do not use electrical appliances or corded phones, as electricity can travel through the electrical and phone lines.  Electricity can also travel through water lines, so it is also a good idea to stay out of the bathtub or shower.

If there is a Severe Thunderstorm Warning in effect for your area, it means that a storm containing wind gusts over 58 MPH or hail over 1" in diameter could be affecting you in the next 15 to 30 minutes.  Tornado warnings are issued either when Doppler Radar indicates that a storm is rotating enough to put down a tornado or when trained spotters have spotted a tornado on the ground.  If a tornado warning is issued in your area, move to the basement in your home.  If a basement is not available, move to an interior room without windows on the lowest floor possible.  It is best to bring a radio with you.  If you don't have a portable radio available, you can turn up your TV loud enough to hear -- we will break into programming when a tornado warning is issued to bring you the latest information.

We are heading into the time of year when we are spending long periods of time outdoors.  Make sure you know how to stay safe when severe weather strikes.

--Meteorologist Brian Thompson

Time to Plan for the Spring Garden..

Stuck inside? The chilly winter months are the perfect time to plan your spring vegetable garden. Use the winter months to plan the right garden location. Pick a sunny area that’s well drained. Consider having the garden close to your house for easy access. Sketch out some ideas of what you’ll plant where and what plants you can grow given your hardiness zone, or the number of frost-free days you’ll have to grow your vegetables.

When you’re planning your spring garden, also think about the time you’re willing to invest in gardening. Don’t underestimate the time it will take you to prepare the soil, plant the seeds, weed and water, and care for the plants as they grow. But remember that those hours spent in the garden can be quite enjoyable and rewarding.

Personally, I usually start my seeds for my garden inside my sun room around St. Patrick's Day. That will give them a good start and they will be ready to go into the ground around late May.

Some of this information was provided by ATTRA through Earth Gauge– The National Sustainable Agriculture Information Service. Learn more about scheduling vegetable plantings:

http://attra.ncat.org/attra-pub/continuousharvest.html.

Spring Is Here - March Preview

I know your calendar may say that spring doesn't start until later in the month, but that calendar is based off the astronomical seasons of which the weather doesn't totally match. Officially, we are now in what is known as meteorological spring which better matches the weather. It marks the quarter of the year that separates what is normally the coldest three months of the year and the warmest three months.

Need proof that spring is beginning? Look to the sun. It is higher in the sky, out more, and is more efficient at melting snow even when the air temperature is below freezing. Also, our average high temperature is now 8 degrees higher than mid-winter and the month of March is the month that we see the steepest rise in average temperatures.

Here are more stats about the third month of the year.

-March is the fourth coldest month of the year.
-It is the fifth wettest month, which interestingly followed the driest month of the year. While increased temperature difference between air masses is the main reason behind this, the numbers are stacked a bit as March contains 3 more days in order to accumulate precipitation.
-March is the third snowiest month, and while it is warmer, it often brings more snow than December.
- We gain 1 hour and 9 minutes of daylight

Now for the numbers for March (based on Altoona):

Average highs: 42 - 54
Average lows: 25-34
Highest temperature: 83 degrees set on the 31st in 1998.
Lowest temperature: -4 set on the 9th in 1943.
Average precipitation: 3.85"
Wettest March: 9.5" in 1936
Average snowfall: 10"
Snowiest March: 33.5" set in 1958