April 11, 2003, 8:10 a.m.
CHANCE TO DRY OUT?
Not counting any rain that fell since midnight, Roanoke was at 14.22 inches of rain for 2003 -- nearly 3 inches above normal. That is quite a switch from the last several years. This time year ago, we were almost 5 inches below normal and headed deeper into the hole.
Beech Mountain, N.C., had 11 inches of snow on the ground late yesterday afternoon at about 5,000 feet elevation. The snow reached down to some of the very highest peaks of the Appalachians, mostly 3,500 feet and higher. Haven't heard any reports, but my suspicion is that the ponies at Mount Rogers might have got some slush on their manes yesterday. It snowed on me when I was there last May 21.
It looks like we will have a chance to warm up and dry out for a while. The next few days will be typical spring, mild days and cool nights, as the soggy turtle-paced upper level low heads away from us. After that, as the jet stream buckles to bring a big storm into the western United States, it will likely swing upward across the eastern U.S., allowing a ridge of unseasonably warm air to develop across the middle of the country. Then, this will come east and might bring us a taste of early summer later in the month.
April 9, 2003, 11:10 a.m.
CUTOFF LOW
It's cold, wet and dreary across Western Virginia ... and we're not getting out of it until the weekend. Some of you might even see a little snow by Thursday evening.
The culprit over the next 48 hours is a booger called a "cutoff low." This is an upper atmospheric pocket of energy that becomes separate from the jet stream and therefore takes its own sweet time moving.
This cutoff low will be over the Mississippi River valley today and will ever so slowly move our way, almost overhead by Thursday.
As it moves our way, it will spin up moisture out of the Gulf of Mexico that will just keep coming, and coming, and coming, tapping the tropics and pumping that warm juicy stuff up over the cold dome of air that's been trapped over us. Were this two months ago, it would be a prime ice storm setup.
One feature of a cutoff low is a deep pool of cold air in the middle and upper layers of the atmosphere. With warm surface temperatures, this can set up instability for hail- and wind-bearing thunderstorms. With cold surface temperatures, another thing can happen: snow!
If you live above 2,500 feet, March 30 may not have been your last encounter with significant snow. As this pocket of cold air edges overhead Thursday night, it's likely that the deep pool of cold air above it will allow some of the precipitation to reach the surface as snow. Some areas might get enough to whiten the ground, maybe a few inches along the highest ridge tops along the Virginia-West Virginia line.
Deeper in the valleys, temperatures will be just a tad warmer but still pretty darn cold, in the mid- to upper 30s. Though I expect nothing like the Bradford pear-crushing March 30 storm, a flake or two even in the valleys cannot be ruled out. Roanoke's "urban heat bubble" might be just enough to keep snowflakes from touching downtown Campbell Avenue, but don't be surprised if you a few pelt the Mill Mountain Star.
Flooding will be the biggest concern, however. Our rocky Appalachian ground, parched not so many months ago, is now a gooey sponge after six months of regular rain and snow. We've already had a steady rain yesterday and last night to swell the streams. Any heavy downpours funneling through the hollows could send those creeks out of their banks pretty quickly, and already high rivers will be on the rise in upcoming days.
The Hydrometeorological Prediction Center puts southwest Virginia right in a 2-inch "bullseye" of rain for Thursday on the heels of an expected half inch this evening.
Well, folks, we were praying for rain a few months ago.
April 7, 2003, 10:50 a.m.
OVERRUNNING WITH RAIN
It's a cold, dank, rainy day in Western Virginia this morning, and a common culprit is at work. Warm, moist Gulf of Mexico air is overrunning a cold air mass from Canada at the surface. The result is a raw, rainy day. Heavier rain should let up later, but it will probably stay damp most of the day.
If you happen to live at a higher elevation, say 3,000 feet or higher, you may notice some ice this morning. Hot Springs, Va., was at 28 degrees last hour. There could be some slick roads along the higher ridge tops.
March 31, 2003, 7:25 a.m.
SNOW JOB
I took my eyes off the ball.
Early last week, this looked like it was going to be a calm week and a good time to catch up on other stuff. So I took a week break from the weather column. There were some puny rain systems and one decent cold front on the horizon. Maybe even some snow showers in the West Virginia mountains for the weekend, but that's hardly an unusual event in March. People even asked me about snow for Sunday and I said it wouldn't amount to much in the Roanoke Valley, maybe a little more in the New River Valley and higher elevations.
I heard pecking on the window early Sunday morning, and after thinking "Is that sleet?" in my grogginess, I went back to sleep. A couple of hours later, I rose to peer out the window. I might have woke everyone else in my apartment building when I shouted "Good grief!" I was stunned, shocked, to see 2 inches already on the ground and big flakes plunging out of the sky. I did not in my craziest notions expect a snowstorm in the Roanoke Valley out of Sunday's setup. Snowflakes, possibly, but not a snowstorm.
Sunday's storm was breathtaking in the precision several elements came together to give us a heavy early spring snow. We knew all week that there would be a cold front, some moisture, upper atmospheric energy, and a developing surface low pressure system on the coast. What we didn't know was just how well-timed all that would play out.
Here's what happened:
1) The cold air established itself more quickly across the area than expected. This allowed snow to begin falling much earlier than expected farther east and at lower elevations. In the Roanoke Valley, snow was not expected until mid-morning, but began before sunrise.
2) The moisture was thicker than anticipated. As a result, forecasts of 2-4 inches in the mountains and less elsewhere suddenly became 8-12 in the higher elevations and 4-8 in the valleys.
3) The strongest upper atmospheric dynamics moved directly over us. Not only did this intensify the precipitation and extend its duration, but it also enabled "dynamic cooling" to occur, as intense precipitation literally pulled even more cold air out of the atmosphere to the ground. This is part of why Roanoke's temperature fell from 42 to 33 in an hour early Sunday morning.
4) The surface low formed in an ideal location off the North Carolina coast. This actually held the precipitation over us a little longer and kept the surface cold air circulating into our area.
5) A factor not to be overlooked in late March: all this came together at the coldest part of the 24-hour cycle, the hours just before daylight. Had it come together at 2 p.m. it might very well have snowed many places but the sun angle even through the clouds might have reduced accumulations and even kept more rain in the lower valley areas. Just a degree or two of temperature change would have been crucial.
Had any one of these factors failed Sunday, we would not have had the tree-breaking snowstorm we did. It was a snow we'll remember for a long time.
Ironic in the "winter" of 2002-03 is that the biggest snow events in our area occurred in fall (Dec. 5-6) and in spring (March 30). In between, during what we call winter, we had a steady stream of little snows and one huge sleet storm that could have been our monster snowstorm of the year under different circumstances. But what we'll remember most about this winter occurred on the bookends.
I think we've all learned over the past four months is that in spite of recent mild winters and lots of hype about global warming, winter is still a real season that we have in Southwest Virginia. We had snow showers on April 18 two years ago, and I saw snow on May 21 on Mount Rogers last year, so I'm not going to write off winter as being over yet this year. I've already been burned.
March 30, 2003, 3:25 p.m.
QUOTING WINTER: "I'M BAAAAACCK!"
Which will be deeper: the accumulation of snow or the accumulation of egg on my face?
Late in the week, I kept dismissing today's spring snow with the words "won't amount to much" to those who asked. I maintained my week-long board silence. Warm ground, cold air moving in too slow, higher elevations get more. I knew better. How many times have I been burned by a late season snowstorm?
Winter's demise has been greatly exaggerated.
Already 3-5 inches on the ground here. Lots of soft-wood trees have snapped under the weight of the wet snow and power is out in many parts of the Roanoke Valley.
March 25
Weather has taken the backseat to war this week, so I'm taking this week off from the weather column.
In the meantime, to check out daily weather conditions for Baghdad, click here.
March 19, 2003, 3:25 p.m.
HERE COMES THE RAIN AGAIN
Fritz Peak, Colorado -- 82.5 inches of snow!
That's nearly 7 feet, and it's still snowing. Still lacks about a few inches to get Shaq-depth. But that's a lot of snow. Next time schools close for 2 inches, think about that.
Now, the same system is headed our way to dump a lot of rain.
The National Weather Service has issued a flood watch for us tonight and Thursday. Looks like widespread 1-3 inch rain in our area. Coming on the soaked ground left by our wet winter, some areas could be in for more flooding.
Welcome to spring.
March 18, 2003, 2:25 p.m.
BLIZZARD, TORNADOES, FLOODING
The weather map is active now in exactly the part of the country that has missed it most of the winter -- the Rockies and the Plains. But we're going to get in on some of the action, too.
A massive low pressure system is gearing up there that will bring a paralyzing blizzard to Colorado and spin off some severe thunderstorms and tornadoes right in the heart of Tornado Alley. To say a blizzard is paralyzing in Colorado is saying a lot, but we're talking snow depths taller than Shaquille O'Neal in some eastern slope areas of the Rockies, extending up into Wyoming and Montana. Denver's snow will be measured in feet. This is an area of the country that has been in a drought this winter. Looks like they're making up for a lot of it at once.
Farther south and east, in the Lower Plains and Mississippi Valley, severe weather will be the problem. According to the Severe Storms Prediction Center, Louisiana appears to be the bullseye for the potential of high winds, large hail and possibly tornadoes. It's that time of year folks, nothing new in those parts.
This storm will move northeast later in the week and will draw up some moisture-enriched Gulf of Mexico air across our area. This will mean a prolonged period of rain Wednesday and Thursday, and some quite heavy rain. Another system already just below us could start us off with a little rain as early as this afternoon and evening. It's a safe bit Carvins Cove won't unfill anytime soon.
It doesn't look like a huge severe weather threat for our area ... the temperature profile of the atmosphere isn't quite right ... but don't be surprised to hear some thunder. Our biggest threat with so much rain and a moist ground from a February full of rain, snow and sleet will obviously be flooding. This could become a major concern for our area of mountains and valleys. Stay tuned.
Copyright 2003
