Kevin Myatt grew up in Arkansas to the tune of tornado sirens and the rhythm of hailstones. Chasing twisters like he did in
1999 and getting within a quarter-mile of one was exciting, but he finally tired of 5-month-long summers and 2-inch snowstorms and moved to the cooler climes of Southwest Virginia's mountains in 1999.
Kevin thought he was going to be a meteorologist growing up but he credits divine intervention with continually detouring him to a newspaper career instead, landing him in an managing editor job of a small Arkansas paper before coming to The Roanoke Times as a copy editor in 1999.
But his love of weather continues to this day, and at the beginning of 2003 he began this weather column in addition to the hiking page he has updated occasionally on Roanoke.com since early 2000.
He now works the copy desk for The Roanoke Times and is its principal weather geek, offering weather reporting training classes to reporters and advising the newsroom on upcoming weather stories. He updates this column most Tuesdays and Fridays -- and other times as conditions warrant. Email your weather or comments questions to kevin.myatt@roanoke.com
For more on Kevin
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Kevin Myatt's
WEATHER JOURNAL
June 30, 2003
TROPICAL STORM BILL SHOULDN'T DAMPEN JULY 4
There is a tropical storm in the Gulf of Mexico after all.
Tropical Storm Bill formed in the western Atlantic on Sunday. It is expected to move north into the coast of Texas or Louisiana. About the only impact we could have for it is increased moisture toward mid-week ahead of a backdoor cold front that will try to drop out of the Northeast our way.
Good news: Fourth of July is looking drier than earlier anticipated as high pressure may start rebuilding by Thursday.
Still don't think we're going to be able to anchor one long enough for a heat wave.
June 27, 2003
TROPICAL WEATHER ON THE WAY
Have you enjoyed the hot, dry weather of the past few days? Don't get used to it. The tropical rain forest is returning.
With a couple of 90-degree days and a code-orange level of mucky ozone blocking my view of the mountains, there's no doubt that it's been summer. But summer in Western Virginia more often than not means humidity and afternoon showers and thunderstorms. That's what's ahead, beginning today and probably continuing through July 4th and beyond.
If you look at the jet stream pattern around the world, it's a series of "ridges" and "troughs." Where the jet stream arches north (in the Northern Hemisphere; flip it south of the equator), there's a high pressure ridge. Where it dips south, there's a low pressure trough. Underneath the highs are generally warm, dry weather; underneath the lows are wetter, cooler weather.
So what's happening into next week is a realignment of the pattern where we will be under one of the troughs instead of one of the ridges. It all starts in the Gulf of Alaska, where a powerful low pressure will dig southeast toward Seattle. This will in turn push up a high pressure ridge over the central United States, which in turn will lead to a low pressure trough over the eastern U.S. It's kind of like whipping a garden hose, and the high pressure we've been under will push out to sea somewhere.
The low pressure trough we'll be under will siphon Gulf moisture in truckloads. But the big high that will bake Kansas and Nebraska will deflect a lot of would-be storm systems from coming across us. So, instead of having lots of cold fronts and such to wring out the moisture in all-day downpours, the humidity will just hang on us like a musty shirt day after day. Any jiggling of it by a puny little atmospheric turbulence or simply by the afternoon sun or our mountainous topography will shake loose showers and thunderstorms. Don't expect rain 24 hours a day all week, but more in bursts concentrated in the afternoon. It's tropical weather.
Some forecasters were getting a little antsy earlier this week when one major forecast model spun up a tropical system in the eastern Gulf of Mexico this weekend. Doesn't look like all the pieces are in place this particular weekend, but keep an eye on the Gulf in the weeks ahead for a possible tropical storm or hurricane. Water temperatures and atmospheric patterns are beginning to get ripe for tropical development in that area.
One weak "cold front" (always a relative term in the summer) will come through this evening or on Saturday. This front is then going to get hung up the next few days just east of us, then just kinda wash out. Stalled and dead frontal boundaries are often a focus for shower and thunderstorm development.
I have real doubts about whether we will have any long period of hot and dry weather this summer. It already seems like the "heat bubble" is having more of a propensity to locate over the Great Plains instead of over the East Coast. Summer weather patterns tend to stagnate, so a lot of times what you see in the first week of July sets the general tone for the next two months.
Also, while La Nina is linked with warm, dry falls and winters for us, summers seem to be a whole cooler and wetter. Summer 2000 was a good example. We never got above 92 that whole summer and were well above normal in rainfall. I think we're in for a sticky summer with a good bit of rain, but more tropical showery stuff rather than the days-long soakers we've had the past 7 months.
Personally, I'm not a fan of hot, dry summer weather. But neither am I a fan of warm, sticky summer weather. Summer is just something to suffer through between spring flowers and autumn colors.
June 24, 2003
LA NINA COMING BACK?
This past fall and winter featured an El Nino episode that was strong enough to give us drought-breaking and ultimately flooding moisture but not strong enough to warm up our winter. Now, there are signs that the pattern has already flipped and we are headed into a La Nina pattern.
El Nino and La Nina refer to the phenomena of changing ocean temperatures in the equatorial Pacific from the coast of Peru west nearly to Asia. When the temperatures are warm, it is called an El Nino -- literally, the "little boy" or "Christ child," as it frequently develops around Christmas. When the temperatures are cool, it is called La Nina or the "little girl."
These ocean temperature cycles have been correlated with weather patterns around the globe. Not perfectly, mind you, and controversially, but you can usually take it to the bank that winter and spring are going to be wetter for us in El Nino than in La Nina.
The Climatic Prediction Center got taken big-time by putting too much emphasis on El Nino in its winter forecast for 2002-03. Seeing the developing warm waters in the central Pacific, the CPC looked back to recent El Nino years and predicted a mild winter for the eastern U.S. What they didn't take into account was (1) the El Nino was not very strong, (2) that El Ninos in the 1960s and 1970s often produced snowy winters and (3) other factors, especially the North Atlantic Oscillation, were pointing heavily toward cold and snow. Furthermore, El Nino almost completely petered out by February and was essentially a non-factor by then.
So, with that caution in mind, what can we expect should La Nina fully entrench itself? Well, "drier" is the first word that comes to mind. We're currently on a record pace for annual precipitation with already over 32 inches in a location that averages about 41 inches annually. If we kept going at this rate, we'd have 64 inches of precipitation by New Year's Eve.
Between the law of averages and La Nina, I think it's a solid bet that the second half of the year will dry out some, maybe considerably, depending on the strength of the La Nina. Strong La Ninas cut off a lot of those strong southern systems that rake the Gulf for moisture, and they also get a fast-moving west-to-east jet stream flow going that doesn't let systems dawdle over us and pour out copious rain for days.
La Ninas are often connected with a burst of hurricane activity in the Atlantic. An El Nino, with its warm Pacific waters, tends to charge up the Pacific hurricane season, robbing energy on the Atlantic side. But a La Nina will dampen hurricane activity in the Pacific, which usually seems to mean that activity on the Atlantic side will be greater. So, if a hurricane came inland and dumped a lot of rain on us, it might offset the dry fall to some extent.
But again, there are so many variables known and unknown, that it can't be said with any certain what the trends will be over the next several months. My guess is for less than half as much rain over the next six months as during the past six.
June 20, 2003
Could it be summer, really?
The first day of summer is Saturday, and believe it or not, we could be in for a real burst of typical western Virginia summer through the middle of next week.
Yes, that means we might actually put consecutive days together without rain.
A high pressure system is expected to build over us from the west, cutting off the moisture pipeline and blocking additional storm systems from coming through. I wrote earlier about how a large high building over us from the west is often a harbinger of prolonged hot, dry summer weather ... this high will be a lesser version of that, but with similar effect, at least for a few days. Expect some sunny, mostly dry days through the first half of next week (can't ever rule out entirely an isolated shower or thunderstorm in our mountain environment), with temperatures trying their darndest to push 90. It will be a welcome break.
The summer solstice, of course, represents the longest day of the year with the most time between sunrise and sunset. It might seem logical that this should be the hottest day of the year, but as you know, temperatures in our area usually peak toward late July and early August.
Think about your fireplace a minute: The room isn't the hottest when the fire burns most fierce to begin. Or even if you have a heater: The room doesn't get hot right when you've got it going full blast at first. It's sometime later that it gets really warm. And that's kindly the principle involved here, a "heat lag" between the longest sun and the biggest heat. Of course, it's been almost a moot point of late since we've seen so little sun. (I see a little poking out even as I write this.)
We'll be keeping an eye on this high pressure long-term, to see if it's going to be transient and push on out next week or become a regular feature in our summer weather. A few weeks of the latter would be welcome news right now, especially for soggy farmers (see today's front-page story in The Roanoke Times), but even that could get out of hand. It takes a lot shorter time than seems right to go from mud to dust. It would be ideal, after 2 or 3 weeks of drying out, to go into a pattern of regular sun and regular rain. But there's almost nothing ever regular about weather.
June 17, 2003
Too wet for triple digits?
Roanoke has not had a 100-degree day, officially, since 1999. The longer this wet pattern hangs on, the less likely we are to have one this summer.
That may seem true on its face, considering that a continued procession of cloudy, damp days would certainly keep the sun from boosting the thermometer to 90, much less 100. But even if the sun breaks through for weeks on end and there is favorable atmospheric pattern for a heat wave, that heat will be tempered by what has already occurred.
Many things are at work. One is the waterlogged ground. Much of the solar energy would be spent evaporating that water, and therefore would not go to heating the atmosphere. As the moisture evaporates, clouds and possibly even heating-type showers and thunderstorms would further offset the heat.
Secondly, healthy, green vegetation is an inhibitor of severe heat, and wet weather is keeping things very green. Leaves absorb sunlight energy; generally speaking, the greener the leaves, the more photosynthesis is occurring, and therefore the more solar energy is absorbed. Leafy trees also shade the ground and keep it from getting baked by the sun.
Major heat waves require first and foremost a stagnant high pressure system overhead that deflects storm systems around it and keeps the air from being stirred. Almost every summer includes one such period of at least a week long. But for the heat to get into the severe category, it usually requires the ground and vegetation to get pretty crispy. The wetter it is beforehand, the longer it takes to do this, and the more unlikely severe heat is.
Roanoke only had four 100-degree days in the entirety of the 1990s and hasn't officially been above 100 since a 102-degree day in 1988. It usually takes a major heat wave to boost our thermometer to triple digits. It seems unlikely to happen this year . . . but then, you never know. It gets sunny and dry at the start of July and stays that way a while, it could happen.
The flip side, however, is that even though it might not be extremely hot, the regular hot we will experience in time may be accompanied by high humidity from all the evaporation occurring around us, so a 90-degree may be just as miserable as if it were 100. It's not the heat, after all; it's the humidity.
June 16, 2003
Not as dry as we thought
After another weekend of mighty rain, it might come as no surprise but also as a disappointment that this coming week now looks a lot less dry than we once thought (hoped).
The backdoor cold front will come through today, but the moist air will keep overrunning it the next couple of days. Quite a bit of gloomy, cloudy, drizzly weather instead of the sunny, dry, fall-like conditions we were thinking might happen. Then, the front retreats and we're back in the warm, sticky, thundery, monsoony type weather by Thursday. Ugh.
June 13, 2003
Winter, summer at the back door
The cool, moist pattern of spring has become warm and moist lately. We've been experiencing sticky days as tropical air has come upon us. The same kind of disturbances that have been flung upon us from the west in rapid succession since last October are coming through, kicking off showers and thunderstorms as the day heats up.
For a few days early next week, we'll get a respite from wet and warm. A front will move down upon us from the northeast, and our temperatures will back down in the 70s in the day and 50s at night. Monday and Tuesday look gorgeous right now ... too bad most of you will be back at work. Not only will it be cooler, but for at least a few days, dry.
Ironically, the "backdoor cold front" that will set up a "cool air damming" situation on the east side of the Applachians is a more winterlike feature being triggered by a typical summerlike one. A large high pressure system is expected to build over the Plains; this will cut off some of the rainy systems they've been getting and also begin to cook all that open real estate. The clockwise rotation around this high pressure system will pull this cold front down on us from New England. Where it stalls in the South and bounces against all humidity for several days, there'll be a lot of rain and thunder. Here, blue skies and bright sun. It'll feel like early fall.
It will be interesting to see if this is the predominant pattern that sets up for most of the summer. If so, we'll stay unsettled east of the main heat, with cold fronts rotated upon us on a semiregular basis. If that happens, it will be a lot like summer 2000 was for us -- moist and cool, with a few wonderful fall-like dry respites.
SCATTERED VS. ISOLATED: I've had two requests in the past few days to explain the difference in showers or thunderstorms being "scattered" and "isolated."
Isolated means one here or there; scattered means they're not everywhere but speckled around the area.
Isolated is a 20 percent chance or less. Scattered runs from about 30 to 50 percent.
Isolated means you probably won't hear thunder today but someone somewhere will. Scattered means you'll probably hear thunder but may or may not see rain.
Or, as one of my questioners said after I answered him: "Scattered is a whole lot of isolated." That's a pretty good description.
June 10, 2003
Hurricane doctor
Nestled in the Rocky Mountain foothills a mile high, Fort Collins, Colo., has never once been hit by a hurricane. But when it comes to hurricane forecasting, it is a world "hot-spot."
For the past 20 years, it's been an annual rite before the start of each hurricane season for Dr. William Gray of Colorado State University to issue his tropical weather forecast for the Atlantic basin. Just like football fans perusing their favorite sports magazines to get prognosticators' predictions on the pigskin schedule to come, Gray's forecasts are eagerly awaited by tropical weather buffs.
Each year, based on a huge number of atmospheric and oceanic factors practically spanning the globe, Gray issues a forecast of how many tropical storms and hurricanes there will be.
In the course of the past two decades, Gray's forecasts have become widely known for almost always being within 1 or 2 storms off being on the money ... and in some years right on target. This is an amazing feat because tropical seasons can vary so drastically in numbers and intensity.
His prediction for the 2003 season is for 14 named tropical storms, 8 hurricanes and 3 major hurricanes (Category 3 or higher). This would be a heavy hurricane season, with 4 more storms than average, 2 more hurricanes and 1 more major hurricane. (We've already had 1 named storm, Ana, in April, the first ever recorded in that month in the Atlantic.)
Gray also suggests there is a 70 percent chance of a major hurricane making landfall on the U.S. coast this year, with a 50-50 shot at one doing so on the U.S. East coast and an almost 40 percent chance of a Gulf Coast strike.
Here in Southwest Virginia, we are often heavily affected by hurricanes that come ashore either in the middle or eastern Gulf or along the coasts of the Carolinas, so should this verify it could have a major impact on what may already be a waterlogged situation for us. A major hurricane strike in the Carolinas could even cause wind damage this far inland, as with Hugo in 1989. But usually, we just get a ton of rain.
Gray was the pioneer of this kind of hurricane seasonal forecasting. The guv'ment boys in D.C.are issuing a similar forecast now, but even that is based largely on Gray's research and with the direct input of some of his Colorado State research associates. The National Oceanic and Atmospheric Administration forecast is very similar, with a little bit more cushion room -- 11-15 named storms, 6-9 hurricanes, 2-4 major hurricanes.
I'll leave it to Gray and his gang to explain the rest of his rather technical, but not entirely incomprehensible, reasoning behind his forecast. Check out his Web site.
June 6, 2003
Between a block and a wet place
In some ways, winter never ended.
There's a huge area of high pressure in the North Atlantic called a "Greenland block." It's a common feature of winter, triggering brief cold snaps in mild winters and practically parking itself like a couch potato in cold, snowy winters like the one just passed. But it's not a common sight for this thing to be hanging around in late spring, as it is now.
This block acts like a beaver dam in a stream, and the atmospheric steering currents have to flow around it. That jet stream reroute dives south from Canada into the eastern United States, carrying cool Canadian cold fronts across us in succession. Each front scoops up a heaping helping of Gulf of Mexico moisture. Warm moisture in cool air is a perfect prescription for damp, rainy weather, like the month of May gave us on 21 of its 31 days.
Aided by a winter-like low pressure system moving northeast out of the Gulf, another episode of rain will kick off our weekend tonight. It could be heavy rain, with 1-3 inch amounts probable across the area tonight and Saturday. Not what we want to hear ... though a year ago we were begging for it.
It looks like intermittent bouts of rain into next week, as well.
The low will also sweep in Atlantic moisture on southeast winds, with the Blue Ridge upslope wringing out even more rain in some areas. If the sun pops out for any time on Saturday, thunderboomers may result as the cold front interacts with the heat and moisture, adding locally heavy rain (and maybe isolated hail or high winds). Short answer: With a waterlogged terra firma already, expect somebody within 100 miles radius of Roanoke to get flooded this weekend.
Is there hope of a dryout? Sure. That's the typical sequence of affairs in almost every summer. There are some signs that by mid-month the pattern will relax, the block will move or dissolve. This could allow hotter, drier summerlike weather to creep in from the southwest. Could, I say.
Keep an eye on the high temperatures in Texas. If the high 90s and 100s stuff starts spreading east and north from there, it could be the sign of a "heat dome" high pressure system building. Lock one of these boogers into place across all of the central and eastern U.S. and it could be weeks of 90s and hazy summer mucky skies.
But if it develops more north than east, we could be caught east of it, and we could keep getting cold front after cold front slung down upon us in an insane precipitation merry-go-round ... not what swimming pool operators would want, for sure.
D-DAY
Today is the 59th anniversary of D-Day, the massive invasion of Normandy that led to Allied victory in World War II. The soldiers who sacrificed or risked their lives in defense of freedom are honored at the National D-Day Memorial in Bedford, of course.
What many folks don't know is that D-Day represented a major victory for Allied meteorologists over Axis meteorologists. German experts did not expect weather conditions would allow an Allied invasion of Normandy on June 6, 1944. American and British meterologists said conditions would favor that. We were right.
BACK AT IT
After taking a break, I'm back at the weather column and looking to keep it going on a regular basis. I hope within a few weeks at least, maybe sooner, to get this back up to twice a week, on Tuesday and Friday, with additional updates as needed. Please send in any questions or issues you would like to see explored here, as I plan to do more articles about broader weather and climate issues that would normally escape daily notice. Anything weather-related is fair game.
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Copyright 2003