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National Weather Service

Making a better severe storm warning

May 22nd, 2020
by Charles Kuffner.
2 comments

Of interest.

We’ve all heard them – the blaring alerts that activate our cellphones or television when a severe weather warning is issued.

Perhaps our favorite weather app sent us a push notification, or we saw a television meteorologist pointing at vibrant boxes on a weather map. Whatever the medium, weather warnings have a way of finding us, especially whenever a severe thunderstorm is close by. Now, those warnings, specifically the way in which they’re generated, are in the process of getting a makeover.

Severe weather warnings are issued for individual thunderstorms; before 2007, entire counties would be alerted at once. Over the years, weather warnings have become more targeted – but one warning can still cover an expansive area. Moreover, conditions can vary wildly even within the region enclosed by a single warning.

Now, the National Weather Service is hoping to change that.

Kodi Berry leads the program that’s updating warnings at the National Severe Storms Laboratory (NSSL) in Norman, Oklahoma. The Forecasting a Continuum of Environmental Threats program, or FACETs, is an endeavor the National Weather Service is pursuing to communicate the hazards posed by severe thunderstorms on a hyperlocal level.

Berry says the goal is provide a more continuous flow of information for those who need it the most.

According to the National Severe Storm’s Laboratory, FACETs aims to improve weather watches and warnings to provide “detailed hazard information through the use of ‘threat grids’ that are monitored and adjusted as new information becomes available.”

Typical weather warnings are issued in the form of polygons digitally drawn on a map. If you’re within the polygon, you’re alerted and urged to take action – such as seeking shelter. But just a stone’s throw away, a neighboring home outside the polygon may not be given any special instructions. The current state of weather warnings is binary, akin to a “yes” or “no” to severe weather.

Berry’s team is hoping to improve that by creating a product that reflects the gray area in between. They are experimenting with displaying probabilities to reflect the range of possible outcomes in a rapidly-evolving severe weather event.

“There has been a lot of social science research that shows that, given probabilistic information, people make better decisions,” Berry said. “If we appropriately define these probabilities and what they mean, people can use them to make better decisions.”

See here for more on the NSSL, and here for more on FACETs. I like the idea overall and agree that more precise information that goes beyond the “threat/no threeat” binary makes sense, but I’m not so sure people make better decisions when given probabilistic information. There’s also a lot of research showing that people are not at all good at understanding risk levels, and at least in a political context it’s common to see people round down small-but-not-that-small probability events to “zero”, or the converse to “one”. I’m a fan of more and better data and so I approve of the idea, I just think it’s likely that how this data is presented and explained to the public will need to be refined a couple of times.

It’s still supposed to be a busy hurricane season

Aug 25th, 2019
by Charles Kuffner.
Comments are off for this post

Hurricane season technically lasts until December 1, but this is the peak of it, so keep paying attention.

Don’t be lulled by a quiet June and July. The real Atlantic hurricane season is about to kick off.

The hurricane season generally runs from June 1 to the end of November. But the next six weeks — “the season within a season” — is regularly the most dangerous and active time for storms to develop in the Atlantic, said Dennis Feltgen, spokesman for the National Hurricane Center in Miami.

Only two named storms have developed in the Atlantic so far this summer. Dry, dusty air from Africa’s Sahara robbed potential storms of moisture, and wind shear spurred by the El Nino climate systems ripped apart budding storms. Now, those brakes on hurricane development are gone.

The result: “A big change in the pattern over the Atlantic, going from a very lackluster quiet weather pattern to a much more active one,” said Dan Kottlowski, the lead hurricane forecaster at AccuWeather Inc. in State College, Pennsylvania. “We are thinking this season will be back-loaded.”

Last week, the U.S. National Weather Service forecast 10 to 17 named storms in the Atlantic. Last year, there were 15, including hurricanes Florence and Michael that killed a combined 96 people and caused more than $49 billion in damage. A storm is named when it reaches tropical storm strength, with maximum sustained winds of at least 74 miles per hour.

You know the drill by now. Tune in to Space City Weather and stay on top of what you need to know.

El Nino 2018

Dec 22nd, 2018
by Charles Kuffner.
1 comment

Here it comes.

Houstonians can expect more rain than usual — and possibly street flooding — this winter, thanks to El Niño.

The National Weather Service forecasts an 80 percent chance for a weak to moderate El Niño this winter, starting around Christmas and lasting through February. In Houston, El Niño means a warmer and wetter winter that could have more severe storms and a higher risk of localized flooding.

Last week’s storm, which brought high winds and street flooding to the region, is indicative of an El Niño storm, said Ken Prochazka, a meteorologist with the National Weather Service in Houston.

“After our wet fall, the ground out there is saturated,” Prochazka said. “When we don’t get a chance to dry out, we’re more likely to have runoff and street flooding.”

El Niño occurs when the temperature of the Pacific Ocean off the coast of South America is warmer than usual. The warm Pacific water affects the atmosphere and causes changes in weather patterns around the world.

In the U.S., El Niño accelerates the North American jet stream, pushing storms from the Pacific across the the country at a faster speed. Storms can move across Texas every three to four days during El Niño, dropping more rain than usual.

Houston typically sees 3.6 inches of rain in January. El Niño can bring more rain than that, Prochazka said.

[…]

Houston last saw El Niño-related storms between 2014 and 2016. The city saw particularly strong El Niño storms in 1997 and 1998. El Niño, which occurs unpredictably, can last for a couple of years, Prochazka said.

It is what it is. All we can do is try to be ready for it.

We’re going to get more big rain storms

May 16th, 2016
by Charles Kuffner.
Comments are off for this post

Better get used to it.

The weather is getting worse, says one expert.

Torrential rains fall in the Houston area more often than they used to, according to an unpublished analysis from state climatologist John Nielsen-Gammon.

Heavy precipitation of any particular magnitude are twice as likely to fall in the Bayou City today as they were in the early 20th Century. Downpours that struck every two years back then come every year on average now. Deluges that used to drop each 100, 500 or 1000 years should fall more frequently as well.

Nielsen-Gammon, a climate scientist at Texas A&M University who was appointed state climatologist by Gov. George W. Bush in 2000, reviewed data from rainfall gauges across the state, some with records dating to the late 19th Century. For Harris County, he drew from 17 gauges.

“We’ve confirmed that there’s an overall increase in extreme rainfall in Texas over the past century,” he said. “Specifically for Houston the increase has been particularly large.”

[…]

An independent analysis of local rainfall data from the National Weather Service also confirmed the state climatologist’s findings. Of the 100 rainiest days in Houston since 1890, as measured at multiple gauge sites, the wettest of the wet are skewed dramatically towards the last four decades.

You can see the charts and graphs and stuff at the story link. If you’re saying to yourself “weren’t we worried just a few years ago that we’d dry out and turns to dust from lack of rain?”, the answer is yes, and the reason is because we’re getting fewer rain events with more rain in them. Fewer rainstorms, in other words, but more of the storms we do get are big, and they’re more likely to come in groups rather than be spread out more or less evenly over time. Isn’t that awesome? But don’t worry, climate change is still a myth propagated by liberals, so we don’t have anything to worry about and we surely don’t have to change any of our habits in any way.

The drought is back

Nov 23rd, 2012
by Charles Kuffner.
1 comment

Bad news, y’all.

The latest report from the U.S. Drought Monitor, released this morning, shows that more than three-quarters of Texas is now in at least a “moderate” drought, and nearly half the state is in a “severe” or worse drought.

Now to be clear, conditions are still far better than 13 months ago, when the great 2011 drought peaked. At the time 100 percent of Texas was in a moderate drought, 99 percent in a severe drought, and 88 percent in an exceptional drought.

But conditions have gotten quite a bit worse since May, when the drought was at bay for about half of Texas, including the Houston metro area. Now the majority of greater Houston has returned to drought conditions.

Although November isn’t over, it’s possible Texas could end with its driest October and November period since 1950, says Victor Murphy, a climate specialist with the Southern Region Headquarters of the National Weather Service.

Statewide average rainfall for Texas in November 2012 should be about 0.5 inches versus a normal of nearly 2 inches, he said. That would make the October/November time period total about 1.3 to 1.4 inches, or about 30 percent of the state’s normal of 4.60 inches.

More from the print edition.

The current October-November period may end up being drier than the same period in 2010, when 1.85 inches of rain fell. That launched the state in the great drought of 2011.

“This is not a good way to be moving into winter,” Murphy said.

Also of concern is the latest winter outlook from the National Oceanic and Atmospheric Administration, which finds that without an El Niño pattern developing in the Pacific Ocean as expected, Texas can no longer look for a wetter-than-normal winter.

The greater Houston region, NOAA says, has an equal chance of above- or below-normal rainfall, and a 40 percent chance of having significantly above-normal temperatures this winter.

Last year’s drought primarily affected Texas and Oklahoma, but this year it has spread to much of the midwestern United States.

More than 60 percent of the contiguous 48 states are gripped by some level of drought, erasing two weeks of improvement, the Drought Monitor reported, with widespread agricultural effects.

We got lucky at the beginning of the year, when winter and spring were far rainier than we had any right to expect. We better hope we get at least some of that luck this winter and spring. Now would be a good time for us all to start conserving water again.

How dry we were

Jan 11th, 2012
by Charles Kuffner.
3 comments

We were drier than ever last year.

U.S. Drought Monitor

How bad is it?

Federal scientists confirmed Friday that Texas had its driest year on record in 2011.

The statewide average rainfall for the year totaled just 14.88 inches, according to the National Climatic Data Center, beating the previous low of 14.99 inches set in 1917.

During the last century, Texas averaged 27.92 inches of rain per year.

Temperature-wise, the state ended the year with its second-hottest mark, 67.2 degrees, finishing just below the record of 67.5 degrees set in 1921.

“Drought begets heat and then heat begets drought, and a feedback cycle develops,” said Victor Murphy, manager of climate services at the National Weather Service’s southern region headquarters in Fort Worth. “We saw this in May through September.”

So, climate change would be bad, then. Just something to think about. The bad news is that the La Niña pattern that drove last year’s dry weather is expected to persist in 2012. So making sure we are doing all we can to not waste water would be a good idea. SciGuy has more.

Hot enough for ya?

Jun 28th, 2009
by Charles Kuffner.
1 comment

Yeah, it’s really hot out there.

Houston’s relentless heat wave prompted the National Weather Service today to declare a “Heat Emergency,” a designation that air temperature and humidity is a potential health threat for all people and is particularly dangerous for high-risk groups.

The emergency designation is expected to last through Friday, said Houston health department spokeswoman Kathy Barton.

Barton said the health department has accordingly invoked its heat emergency plan, which involves working with Metro to bring people to designated cooling centers, such as libraries, and generally urging people to take extra precautions to stay inside.

It is not uncommon for the weather service to declare a heat emergency in Houston, though it didn’t happen last summer. Such an emergency is declared when the heat index, a computation of air temperature and humidity, reaches 108 degrees on two more consecutive days.

The index reached 108 Wednesday and is expected to reach that level today and Friday. Houston’s actual temperature hit 104 degrees Wednesday, the hottest it’s ever gotten in June.

It’s pretty much a given that any time there’s an extra cold winter day somewhere, the global warming deniers point to it as evidence that it’s all a hoax. Here’s a recent example of that, from someone who unfortunately was in a strong position to emasculate the just-passed climate change legislation. This kind of thinking is stupid on many levels, not the least of which is that if a bit of unseasonably cold weather means global warming is a myth, then what does a record heat wave imply? Not that logic is a strong suit for the head-in-the-sand crowd, but you’d think this sort of thing might have occurred to them. Ah, well. At least so far there’s no evidence that this means a worse hurricane season is in store. I’ll take my silver linings where I can find them.