Tuesday, July 30, 2013

OK ... Where are the 90s?

I've resisted getting sucked into this "where are the 90s?" talk, because I figured that was a foolproof way of triggering an all-out heat wave.

But we're approaching the end of July, and it appears almost certain that we'll finish the month with only four 90-degree days.

Clouds and rain, possibly heavy, are likely Wednesday, for the last day of the month.

That will give us a grand total of eight 90-degree days so far this summer -- four each in June and July. We had 23 days of 90 or hotter at this point last year, and that wasn't a terribly unusual summer.

So I'm game ... where are the 90-degree days?

I was looking at some long-range forecasts for August, and while I'll focus more on that tomorrow or Thursday, suffice to say that there are no major changes in sight.  It looks like we'll continue the current pattern for a week or two, then perhaps slide back into a real stormy and wet period (similar to late June and early July).

We certainly won't tie the all-time record for fewest 90-degree days. That mark is eight, set in 1967. We're already there, and it's not reasonable to expect we won't get another 90-degree day this summer. That also probably puts the No. 2 mark (nine, in 2003) and the No. 3 mark (11, in 1910) out of reach.

But we might be somewhere in the neighborhood of 12 to 14 days of 90 or warmer this summer, and that would be in the top 10 (or bottom 10) of 90-degree days in Charlotte.

Monday, July 29, 2013

The tropics: The Carolinas' 'elephant in the room'

As the absolutely insane rainfall numbers continue to mount this summer across the western Carolinas, the tropics loom increasingly large as a source of concern for the next few months.

The hurricane season likely will be ramping up during the next several weeks, and we should be concerned with then activity we've already seen.

In short, an active hurricane season along the Southeast coast could be absolutely devastating in the western Carolinas, given the heavy precipitation we've already received.

The tropical pattern so far:  Systems have formed in the Cape Verde area of the eastern Atlantic (a lot earlier than is usual in the season). They've followed a generally westward path, in a corridor that includes Hispaniola and Puerto Rico. So far, strong westerlies and dry air have shared apart the systems, and that was the case with Tropical Storm Dorian last week.

Eventually, however, those westerlies are expected to relax. Westward-moving tropical systems will be able to intensify as they approach the continental United States, and we could be looking at a steering pattern similar to September 2004, when several storms made landfall in eastern Florida before sweeping across Georgia and the western Carolinas.

The remnants of hurricanes Frances, Jeanne and Ivan caused major flooding in the Carolinas foothills and mountains that year.

Now, fast-forward to 2013.  We've already received staggering amounts of rainfall in the region.

WCNC meteorologist Brad Panovich has been keeping tabs on Brevard, west of Asheville. He notes that Brevard's rainfall total this year is 72.02 inches. That's more than 17 inches above the record total for the WHOLE YEAR!  Greenville-Spartanburg and Asheville have received about 10 inches more than average rainfall in July.

Take a look at this chart on Panovich's Facebook page -- it's a list of where various reporting stations stand, at this point in the year, for rainfall. If you see a "1" next to a city, it means that reporting station is on track for its rainiest year ever (Brad Panovich's page).

In the last week, automated gauges have reported more than 6 inches of rain at Triplett (Watauga County) and at Claremont (Catawba County). There are several reports of 12 to 15 inches of rain having fallen since late June in parts of northern Mecklenburg and Cabarrus counties.

There are places in my yard where my lawnmower hasn't reached since June.  It's simply too wet to mow.

Add a dying tropical storm, with its 6 to 12 inches of rain, and you have catastrophic flooding.

The tropics are always important to people in the Carolinas, but they'll be even more important this year.

Thursday, July 25, 2013

First take on Dorian ...

Tropical Storm Dorian has been a threat only to fish so far, as it remains far out in the Atlantic Ocean.  It will be a few days before the storm nears any land masses, and by that time, it might have dissipated.

Most of the computer models take Dorian on a west-northwest track for the next couple days, but its future is really a question mark.

Working in favor of the storm's development ... Dorian is working with a moist atmosphere, and there is little wind shear to disrupt its organization.

Working against development ... Marginal surface sea temperatures (although Dorian will be moving into warmer waters later today and Friday), and the forecast of stronger wind shear and drier air later in the week.

Historically, most storms forming in the Cape Verde area this early in the year curve away from the Southeast coast, and that's entirely possible this time.  For the next few days, Dorian will be steered to the west, along the south side of a high pressure ridge in the Atlantic.

A trough is forecast to develop along the East Coast this weekend.  If the trough is deep, it would capture Dorian during the weekend and steer the storm northward, away from the United States. But there are some forecasts of a weak trough. In that case, the storm would continue westward, possibly threatening the Bahamas and the Florida coast by early next week.

As you all know, it's far too early to make a solid prediction.  But we should have a much better idea by late Friday or Saturday.  By then, the "wild" guesses will turned into "educated" guesses.

Thursday, July 18, 2013

July 1916 -- Carolinas' monster flood

Round after round of heavy rain belted the western Carolinas from early June through the middle of this month, washing out roads and causing plenty of damage across the region.

Some of the flooding along Mountain Island Lake was the result of heavy rain falling in the mountains, then coming down the Catawba River and its chain of reservoirs.

But the real king of July floods came 97 years ago.

A reader in Catawba County reminded me of the July 1916 floods, which were responsible for some of the worst storm-related damage ever in the Carolinas.

And as I've written many times before, it all was the result of a dying tropical weather system -- not a full-fledged, land-falling hurricane, but what was left of one. Tropical systems that move inland are capable of producing gigantic rain totals, as we learned a couple times since Tropical Storms Jerry (1995) and Danny (1997) came through the Charlotte area.

The 1916 flood was caused by the remnants of a hurricane which made landfall early Friday, July 14, near Charleston. There was little damage in the Lowcountry of South Carolina, but as the hurricane moved inland and weakened, the heavy rains spread rapidly and intensified in the mountains.

Charlotte got only 5.15 inches of rain from the storm, although sustained winds of 40 to 50 mph caused plenty of problems with downed trees and structural damage.

In the mountains, the orographic effect of incredibly moist air rising in altitude triggered extremely heavy rains. There were measurements of 20 to 24 inches in some mountain areas from July 14-16.

A recording station at Alta Pass in the mountains logged 22.22 inches, a record for a 24-hour period in the United States.

Damage, in 1916 dollars, was estimated at more than $21 million. The death toll was a guesstimate, but the number of 80 fatalities was mentioned in several reports.

Extreme flooding was reported in places like Lenoir, Taylorsville, Statesville and in the mountain counties. Dozens died, roads were completely wiped away, and businesses were destroyed. I read one account of flooding washing away a cemetery, leaving nothing behind -- not even the graves.

Just as was the case this summer, the heavy mountain rain drained into the Catawba River's headwaters and rushed downstream.  In 1916, however, there was no chain of reservoirs.  Duke Energy this month was able to regulate the water flow through the various reservoirs and prevent a widespread outbreak of serious flooding. That wasn't possible in 1916.

So the Catawba River roared out of its banks, washing away bridges and roads.

Residents near Mount Holly stood a distance away from the raging river and watched debris float downstream. They say livestock, parts of houses, sections of bridges, trees.  All of that had been uprooted farther up the river and was headed toward South Carolina.

The Southern Railway bridge north of Mount Holly collapsed on the evening of Sunday, July 16, with 18 reported deaths.  As darkness fell, according to reports, some of the men grabbed on to trees in the river in an effort to survive. By the next morning, the trees were submerged.

By some estimates, the river rose 50 feet above its usual level.

Late on the 16th, the Southern Railway bridge in Rock Hill collapsed.  When that 500-foot span went down, rail traffic between Charlotte and Jacksonville was halted.

You can find a number of accounts of the flooding, but two that I found interesting were from UNC-Asheville and from a historical study in Catawba County.

If you're not a native of the Carolinas -- as many of us are not -- the July 1916 flood gives you a healthy respect for the incredible amounts of rain that can fall in a hurry around here, especially when the tropics are involved.

Wednesday, July 17, 2013

Rip current deaths 'shocking'

Rip current deaths along the Carolinas coast are a sad part of the annual vacation season, but the number of fatalities this month is really staggering.

By my count, there have been at least nine people killed on Carolinas beaches since July 3, and a 10th person is missing.  Dozens of rescues have been reported, and a number of people were hospitalized with serious complications from their time in the surf.

The deaths have ranged geographically from the beaches north of Wilmington down to near the South Carolina-Georgia border.

Interestingly, there have been no reports of rip currents deaths from the area where they are most dangerous -- the Outer Banks.

It's almost a cliche to say that people don't understand rip currents, but I'm most surprised at how many of the victims are Carolinas residents who should be more familiar with the risk.

One official of a small town along the Carolinas coast told me last week that "it's one thing to understand what to do in a rip current, but quite another when you're actually being dragged into deeper water."  I understand that point.  Fear and panic make us forget what we should know.

The high death toll this month caught the attention of Dr. Robert Brander, a professor at the University of New South Wales in Sydney, Australia.  He wrote me last week, saying he is a surf scientist who focuses on rip currents and has set up a safety program titled "The Science of the Surf."

"We have made great inroads educating people about rips here in Australia," Brander said, "but the drownings in the U.S. this year have been shocking."

Brander has assembled an interesting rip current website, and I recommend you take a look at it -- especially if you're planning a beach trip anytime soon (and don't forget that rip currents also take place in the Great Lakes).

While you're at it, you can participate in Brander's survey on rip current awareness. You'll find it here.

Tuesday, July 16, 2013

Charlotte: 16th-hottest metro area in U.S.

You couldn't prove it by this summer's temperatures, but a website that ranks the nation's cities and metro areas in various categories says Charlotte is among the United States' hot spots.

Quality of Life writer Bert Sperling's list of "Sizzling Cities" has Charlotte ranked 16th among the country's 50 largest metro areas in the category of heat and humidity.

We're hotter than Raleigh and Atlanta, incidentally.

As you might imagine, Phoenix is No. 1.

The survey (available here), released on the Sperling's BestPlaces website, ranks cities according to average high and low temperatures in summer, plus the average dew point and the relative humidity at the warmest time of day.

Humidity, for example, pushes the Houston-Sugar Land-Baytown metro area into fourth place, even though its average high and low temperatures are not as high as some cities ranked lower.

And overnight temperatures were included, Sperling says, because nighttime heat can be especially difficult on those suffering from hot weather.

"Nighttime heat is especially bad, because your body never has a chance to recover," says Eli Jacks, of the National Weather Service.

So here are the hottest large metro areas in the country:

1. Phoenix-Mesa-Scottsdale

2. Las Vegas-Paradise

3. Dallas-Fort Worth-Arlington

4. Houston-Sugar Land-Baytown

5. Austin-Round Rock

6. San Antonio

7. Miami-Fort Lauderdale-Pompano Beach

8. New Orleans-Metairie-Kenner

9. Orlando-Kissimmee

10. Tampa-St. Petersburg-Clearwater

11. Jacksonville, Fla.

12. Oklahoma City

13. Riverside-San Bernardino-Ontario, Calif.

14. Memphis

15. Birmingham-Hoover

16. Charlotte-Gastonia-Concord

17. Virginia Beach-Norfolk-Newport News

18. Raleigh-Cary

19. Atlanta-Sandy Springs-Marietta

20. Richmond

At the bottom of the 50 metro large areas are San Francisco (48th), Portland (49th) and Seattle (50th).

Sperling also ranked the complete list of 361 metro areas in the country.  In that list, Yuma, Ariz., was the hottest place in the country, followed by El Centro, Calif.,  and then Phoenix.

The coolest were -- surprise! -- Fairbanks and then Anchorage.

Here is where Carolinas metro areas ranked on the overall list:

55. Charleston

75. Florence

77. Columbia

78. Augusta (Ga.)-North Augusta (S.C.)

81. Wilmington

82. Fayetteville

83. Sumter

85. Goldsboro

90. Myrtle Beach

91. Greenville, N.C.

99. Charlotte

100. Rocky Mount

102. Anderson

103. Jacksonville

113. Spartanburg

119. Burlington

123. Greensboro

126. Durham

140. Greenville, S.C.

151. Winston-Salem

234. Asheville

Monday, July 15, 2013

Don't celebrate lack of 90-degree days ... not yet

You've probably heard the statistic about the relative lack of 90-degree days so far this year in Charlotte.

Through Sunday, there had been only four days this year of 90 degrees or warmer in Charlotte. If you don't like the hot weather, I wouldn't get too excited about the rest of the season.  It wouldn't take much to make major changes in that statistic in a hurry.

Obviously, the small number of hot days is a result of the heavy rainfall we've received since the beginning of June. Clouds and storms have kept high temperatures bottled in the 80s.

As National Weather Service meteorologist John Tomko noted, it's not as if the weather has been cool.

"Even those days with highs in the low and mid 80s have been very humid," Tomko says. "The morning lows were in the low 70s most days."

If the persistent upper-level low pressure system leaves our area alone for a while, just sit back and watch high pressure do its thing.  There's a tremendous amount of moisture in the ground and the lower levels of the atmosphere, due to all the recent rain. That will serve to carve a few degrees off the daily high temperatures, but once some drying takes place, we could see a lot of 90s in a hurry.

Several 90-degree days are forecast this week, and we could see more of that later next week.

And there is still all of August and September ahead.

In 2009, when we had a relatively small number of 90-degree days (28), nearly half of those came in August (13).

The least 90-degree days in a year was 8, in 1967. We came close to equaling that mark in 2003, with 9.  The most was 88, in the brutally hot summer of 1954. And we came close to equaling that mark also, in 2010, with 87.

We had 49 days of 90 or hotter last year, down from the 73 of 2011 and the 87 of 2010.

Thursday, July 11, 2013

Some wild rainfall numbers from our crazy summer

The seemingly endless string of rainy days this summer in Charlotte and elsewhere in the western Carolinas is keeping National Weather Service meteorologist John Tomko very busy.

Tomko keeps statistics at the Weather Service's office in Greer, S.C., and he's amazed at some of what has happened in recent weeks.

"It's really hard to believe, in a way," says Tomko, who has been at the Greer office for nearly two decades. "The numbers are wild."

Today's flooding in northwest Charlotte is merely the latest chapter.  In recent weeks, we've had significant flooding events in Mecklenburg, Lincoln and Cabarrus counties on June 28; in Anson, Cabarrus, Stanly and Montgomery counties on June 30; in Caldwell and Watauga counties twice last week; and most recently on Wednesday in Asheville.

And that's not a complete list.

Tomko lives in Polk County, along the N.C.-S.C. border, north of Greenville-Spartanburg.

"So far we've had 51.5 inches of rain at my house this year," he said. "That's about the average for the entire year."

Here are some other statistics, courtesy of Tomko and myself:

-- Rain has fallen somewhere in Mecklenburg County daily since June 23.

-- Since June 1, more than 11.7 inches has fallen at Charlotte Douglas International Airport, Charlotte's official measuring station. That compares to 5.18 inches in an average year during that time.

-- Parts of northern Mecklenburg and Cabarrus counties have received more than 16 inches since June 1.

-- Rain has fallen on 79 of the 192 days so far this year in Charlotte. That puts us on pace for the 10th-highest number of rainy days in a year.

-- Asheville, which has received about 15 more inches than Charlotte so far in 2013, is only 18 inches away from setting a record for the whole year. The city would have to average only 2.8 inches a month for the rest of the year to break a record. That's very possible.\

-- Greenville-Spartanburg is on pace for its second-rainiest year on record.

-- Thanks to the rain and clouds, we've had only four 90-degree days this year in Charlotte. The record for the smallest number of 90-degree days is eight.  So we're likely to finish with one of the smallest number of 90-degree days in a single year.

 -- Meteorological summer runs from June 1-Aug. 31.  So far, our 11.7 inches during that period puts us on pace for the wettest summer ever.

The scary thing is we haven't entered the heart of hurricane season.  If a couple dying tropical storms were to pass through the region, we easily could pick up 4, 5 or 6 inches in a single day.

By the way, we're not alone.  Toronto set a single-day rainfall record earlier this week, with more than 5 inches falling in many parts of the city as thunderstorms repeatedly formed and crossed the area. They're under part of the same pattern that has brought the heavy rain to the Carolinas this summer.

Wednesday, July 10, 2013

No Chantal, but plenty of water?

Tropical Storm Chantal has confounded the experts this week and done little of what was expected.

Now the question is:  Will Chantal ever have any impact, even indirect, on the Charlotte region?

"That is not a pleasant thought to consider," says John Tomko, of the National Weather Service's office in Greer, S.C.

On Tuesday, Chantal was a feisty little tropical storm with 65 mph winds and an apparent path toward Hispaniola and Cuba.  Forecasters expected the mountains of those two islands to disrupt the storm's circulation, but they thought it would emerge this weekend over the Bahamas as a weak tropical storm.

After that, computer models were pointing Chantal toward the Southeast coast -- possibly South Carolina.

Now all that has changed.  As of mid-afternoon Wednesday, it appears as if Chantal no longer exists as a storm with circulation.  Air Force hurricane-hunting planes have been flying into the storm area for several hours, and there is no real sign of a closed circulation.

It appears as if Chantal is now just a tropical wave.  In the late-morning summary from the National Hurricane Center, meteorologist Lexion Avila said the official forecast is for the system to dissipate by early this weekend.

And, by the way, Chantal won't even cross Hispaniola.  It has taken a more westerly track and will miss the island.

That leaves a lot of questions.  The moisture from Chantal likely will remain somewhere in the Bahamas or possibly the eastern Gulf of Mexico by late this week.

Computer models predict a weakness in the atmosphere that would allow that moisture to stream northward, but the question is whether there is enough moisture left in the remnants, and exactly where that northward track would be.  Would it affect the eastern Carolinas?  Charlotte and the western Carolinas?  Georgia and Tennessee?

We don't know yet, and weak tropical systems are very difficult to predict.

One thing is for sure ... any moisture from a dying tropical system would be bad news for the water-logged western Carolinas.  Areas much farther to the west, where rain is badly needed, would appreciate Chantal's remnants a lot more than we would.

Tuesday, July 9, 2013

Chantal bears watching in the Carolinas

Mountains and hurricanes are not a good match, and Tropical Storm Chantal appears to be on a collision course with the high country of Hispaniola.

But it is increasingly clear that if some semblance of a tropical storm survives the trek over the Dominican Republic and Haiti in the next few days, Chantal could be a big problem for the Carolinas.

The system's threat isn't high winds and storm surge.  Rather, it could bring heavy rain into an area that doesn't need it.

Early Tuesday afternoon, Chantal's center was about 325 miles southeast of San Juan, Puerto Rico. It was racing to the west-northwest at 29 mph -- the kind of speed that often tears apart a tropical system. Chantal, which had top sustained winds of 65 mph Tuesday afternoon, is expected to hold its own until it reaches Hispaniola later Wednesday.

A hurricane watch is in effect for the Dominican Republic, and tropical storm warnings are posted for Puerto Rico, the Dominican Republic, and the north coast of Haiti. Tropical storm watches are in effect all the way into the Bahamas.

National Hurricane Center specialists and other meteorologists who follow tropical systems aren't sure what sort of storm will emerge from Hispaniola.  The official forecast from the Hurricane Center is for a system with 40 to 45 mph winds to come off the coast.

There will be one other big change.  Chantal will slow down -- a lot.  The high pressure system that is steering the storm now is expected to weaken, allowing Chantal to curve northwestward toward the Bahamas and the Southeast coast.

In fact, by the weekend, Chantal will be crawling.  It is expected to be in the southeast Bahamas on Friday morning and move only to the northwest Bahamas by Sunday morning.

Then what?

The computer models are coming to the conclusion that Chantal will move toward the South Carolina coast, on a northwest track.

A lot of things can happen between now and then ("then" being later Monday or Tuesday), but that track would bring heavy rain into South Carolina and either Georgia or western North Carolina.

By the way ... Another low pressure circulation is emerging from Africa into the eastern Atlantic. Some computer models predict that system will quickly take on tropical characteristics and move westward.  Chantal and the new system are Cape Verde storms, forming in the eastern Atlantic.

It's pretty early in the season for Cape Verde storms, but that might be a sign of what's ahead this hurricane season.

Friday, July 5, 2013

Still wet, but in a different way

After several days of frequent showers and mostly light thundershowers, the weather pattern in the immediate Charlotte area will change over the next few days.

We'll move to a pattern of sunny breaks, mixed with an occasional thunderstorm.  Some of those storms could be strong.

Persistent upper-level low pressure responsible for all the rain in recent days is being shoved westward. That means the steadiest rain will fall over the mountains and in Tennessee and Georgia.

In the Piedmont and parts of the foothills, we'll see a bit more sun. That will allow the atmosphere to become quite unstable, and that also means thunderstorms will be more frequent.

With more sunshine and a destabilized atmosphere, the storms could grow strong to even severe.

But we'll also see periods of sunshine, especially Friday and Saturday. A weak low pressure system might arrive Sunday. That would throw more cloudiness into the mix.  Then it's back to a typical summer pattern next week -- heat, humidity, and a chance of afternoon and evening storms.

Wednesday, July 3, 2013

Why this strange weather?

The pattern which has been the dominant player in Carolinas' weather this week (and, really, a lot longer) is expected to break down this weekend.

But the real question is whether things really will change for very long.

We're accustomed to seeing weather systems move west to east, or northwest to southeast. This time, the pattern is moving east to west.

Throughout the week, the Carolinas -- and much of the eastern United States -- have been in the combat zone between Bermuda high pressure and a large upper-level low pressure system centered somewhere near the Mississippi River. A third player in the weather has been an old stationary front, stuck across North Carolina.

The Bermuda high's clockwise flow of air and the Mississippi Valley low pressure's counter-clockwise flow met over the eastern United States. That strong southerly flow brought plenty of moisture into the Carolinas. And occasionally, weak low pressure systems moved along the same channel.

All of that combined to create an extended period of unsettled weather.

We've talked a lot about the heavy rain and storm damage. The rain totals actually are amazing, and I'll report on that later this week. But another part of the story has been the temperatures.

A year ago at this time, we experienced three consecutive 104-degree days in Charlotte. This year, our high temperatures have struggled to reach 80 degrees. It's because of the thick cloud cover. Believe me, if the clouds weren't there, we'd be in the upper 80s and low 90s, which is typical for this time of year.

Instead, we're about to experience a very unusual Independence Day in Charlotte.  Our highs probably won't climb above the lower 80s.

Anyways, back to the pattern change.

The Bermuda high is strengthening, and it's pushing the upper-level low farther to the west. As the Bermuda high grows stronger, it's spreading drier air into the Carolinas and along the rest of the East Coast.  Gradually, day by day, larger chunks of the eastern United States are experiencing a decrease in storm activity and an increase in sunshine.

It happened Wednesday on the Carolinas coast.  By Thursday, I expect places like Raleigh and Fayetteville to see the sun for at least part of the day. That pattern reaches Charlotte by Friday.

As that happens, the wettest weather gets pushed westward.  The mountains are in for a soaking Fourth of July, and that pattern will move back into Georgia and Tennessee over the next few days.

My question is:  Will the pattern shift back again?  Will the Carolinas and the rest of the eastern United States find itself back in the atmospheric war zone again soon?

As I've written before, the location and strength of the Bermuda high makes me a bit nervous about hurricane season.  The clockwise flow around the high could serve as a very effective steering mechanism for tropical storms and hurricanes, sending them into the Southeast Coast.