Tracking Hurricane Florence through the Wilmington weather file

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I was always curious what a hurricane would look like on a weather file, so I downloaded
the current year weather file for Wilmington North Carolina, processed it and plotted the
days around the time the hurricane struck.? Here are the results.? Take a look at the wind
speed and rain plots. The wind speed reached a maximum of 61 MPH and the rainfall at more
than an inch per hour, both on Friday morning September 14th.

I'm going to put these graphs on the White Box Technologies website as soon as my
webmaster tells me how, so that I can update them couple of times a day over the next
three days.

Joe

--
Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
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(c) (510)928-2683
"building energy simulations at your fingertips"

-----------------------------------------------------

Weather conditions in Wilmington North Carolina as reported on the Integrated Surface
Hourly Database (ISD) maintained by the National Center for Environmental Information
(NCEI), Asheville NC.

Station name: NC_WILMINGTON-IAP_720630

Time ISD data was accessed Sept. 15, 2018 22:30 pm

Time of last data record on ISD file Sept. 14, 201814:00

**solar radiation calculated by White Box Technologies based on cloud cover and other
weather parameters.*

--
Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"

Joe Huang's picture
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Joe,

Great observations! BTW, do the TMY-type methodologies allow for disregarding (or at least flag) these types of events as outliers? Just curious...

Larry
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Larry,

Wind Speed is not usually one of the items for selection of TMYs but
one would hope that other factors might disregard those events/months.

Linda

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Larry, Linda, others,

Average daily wind speed has always been one of the parameters used to select "typical months" in the TMY methodology used by NREL that others like me have followed to create the IWEC2s, etc. Its weight, however, is low compared to the cumulative weights for temperature (average, max, min dry-bulb), humidity (average, max, min dewpoint), and solar ( average global horizontal and sometimes also direct normal irradiance). The other thing to consider is that the TMY methodology does not exclude any month due to outliers, but looks at the difference in the cumulative distribution of these daily parameters to the long-term distribution, and picks that month with the best correspondence of CFDs. Thus, it is possible that a month with an extreme event might still be selected, but the fact that a hurricane affects all 8 or 9 parameters and can extend over several days makes it unlikely. On the other hand, if the statistics were to pick a month with a hurricane, is that really a problem? One of the things I like about the TMY methodology is that it aims to pick a month with the most representative distribution of conditions, not the blandest month with no peaks and valleys.

Sent from my iPad

Joe Huang's picture
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(updated through Sept. 16th 0:00)

I was always curious what a hurricane would look like on a weather file, so I downloaded
the current year weather file for Wilmington North Carolina, processed it and plotted the
days around the time the hurricane struck.? Here are the results.? Take a look at the wind
speed and rain plots. The wind speed reached a maximum of 61 MPH the morning of Sept. 14th
and then dropped to 0 . The rainfall peaked at about an inch per hour the moring of Sept
14, stopped in the afternoon for a day, and then reached a higher peak of 2 inches per
hour near midnight Sept. 15th.

I'm going to put these graphs on the White Box Technologies website as soon as my
webmaster tells me how, so that I can update them onces a day over the next three days.

Joe

Weather conditions in Wilmington North Carolina as reported on the Integrated Surface
Hourly Database (ISD) maintained by the National Center for Environmental Information (NCEI).

Station name: NC_WILMINGTON-IAP_723020

Time ISD data was accessed Sept. 17, 2018 12:45 am

Time of last data record on ISD file Sept. 16, 201800:00

**solar radiation calculated by White Box Technologies based on cloud cover and other
weather parameters.*

**

Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"

Joe Huang's picture
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Reputation: 406

To layer on to and supplement Joe?s response, I think another neat factoid to consider is that while the TMY protocol generally does not exclude any specific months on the merits of ?extreme? weather/climate events (which is good and rigorous from a statistical viewpoint), there were two historical volcanic events that have caused specific periods to be excluded from files in the NREL TMY3 set: The eruptions of El Chich?n, Mexico in 1982 and Mt. Pinatubo, Philippines in 1991.

These events had substantial effects in reducing solar radiation measured in the United States due to aerosols pushed into the atmosphere, and as a result there are a net of ~6 years pulled out of the historical record to exclude periods following those events, for the purpose of establishing the months of data considered for the TMY ?pools.?

A fun (?) takeaway is that when the next major volcanic event occurs, we as a community are going to have a lot to talk about in considering the merits and application of the established TMY protocol against some other approach to incorporate the weather measurements on record for those excluded periods!

~Nick

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Nicholas.Caton at schneider-electric.com's picture
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Nick,

Nice to read your comments.? The reason I'm skeptical of attempts to unilaterally weed out
extreme events from "typical year" data is that our definition of what comprises an
extreme event can change over time.?? If we are to believe the scientific consensus on
climate change, extreme events would be more frequent and longer lasting in the future.?
If the frequency gets high enough so that there's one extreme event a month - not
necessarily a hurricane but rather a tropical storm or heat wave - then shouldn't such an
event be reflected in the "typical year" weather file?? I'd like to see the "typical year"
methodology modified from producing the most typical weather of the past X number of
years, to what would be? the the most likely typical weather for the future.

Joe

Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"

Joe Huang's picture
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We've been playing with just running models with the last X years of actual
weather data and taking the median performance for what we're curious
about. This is super useful when you aren't concerned with energy, but
instead peak demand impacts. TMY methodology doesn't work for peaks. If
you're calibrating to actual weather data, it's not too hard to run the
last 10 years or whatever to develop your weather-normalized objective. In
design, yes, this is going to be harder.

Trying to extrapolate to future weather is something that seems like it's
worth pursuing. Didn't I see something about that?

On Mon, Sep 17, 2018 at 3:29 PM Joe Huang via Bldg-sim <

Justin Spencer's picture
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Concur with your earlier email Joe, the selection criteria and weighting I think would tend to solve itself, but if these months did get into the selection ? then they should be in the selection?

The example of excluding data during volcanic eruption makes sense ? weather was affected globally by those events over the course of several years. Hurricanes are big, but relatively short duration in terms of weather and affecting weather stations within an area to some degree and gradually less as you get further inland?.how would we decide which get blocked out? I say let the statistics take care of it.

Looking at a future need for ?resiliency weather files? this might be interesting to have a flag that shows times when a building expects to run generators, or incur irregular business operations.

Anyone down the road calibrating a model in Wilmington NC during 2019 looking back at the actual weather data for 2018 would need to know that there was a storm event that caused business to be suspended and/or power to go out ? or in the case of the hospitals and civic buildings maybe the energy use and occupancy goes up due to continual operation / increased loads from displaced people.

It could be a legitimate question for ESCO funded projects looking at their models ?what happens if? due to storm events. Did the building run more or less efficiently (and resiliently) after some upgrade? What?s the correction to be made for any contract based on the savings. Maybe more for federal facilities that embrace this project delivery method.

David

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This will be my final update on Hurricane Florence since the weather has pretty much
returned to normal, whatever that is...? Besides, I think I've milked this news cycle
enough already :-)

In case anyone wants to play around with the weather file, I've put it here

, but be forewarned that the data stop on Sept. 18.

Final comments re: data from Sept 16-17:
I don't believe the solar numbers at all.? These are calculated based on the? cloud cover
reported as a constant? 0.4 over the past 80 hours; it's perfectly understandable the
meteorologists might have been too swamped by other tasks to bother recording the cloud
cover, but it does bring up one of my pet peeves that when people opine on solar models,
they only attribute defects to the models and never to the input data. Readers may be
aware that for the past year and more, I've been replacing my modeled solar with
satellite-derived solar; the primary reason is not the improvement in modeling, but more
reliable recordings of cloud conditions.

Joe
---------
Weather conditions in Wilmington North Carolina as reported on the Integrated Surface
Hourly Database (ISD) maintained by the National Center for Environmental Information (NCEI).

Station name: NC_WILMINGTON-IAP_723020

Time ISD data was accessed Sept. 18, 2018 1:15 pm

Time of last data record on ISD file Sept. 18, 201800:00

*
*

**solar radiation calculated by White Box Technologies based on cloud cover and other
weather parameters.*

*
*

**

Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"

**

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