Friday, November 1, 2019

Frightfully Stormy Halloween 2019 Weather: An Overview -OR- Wet Jack O' Lanterns, Night Time Squalls, and Blade Runner Beginnings

Note: I finished and posted this entry mid-afternoon on Sat., Nov 2nd, but I am giving it a Fri., Nov 1st timestamp as I intended to post it then (and it was partly composed then).

A pumpkin carved into a artistically done jack o' lantern, Gaithersburg, Md., 9:33 p.m. Oct 28, 2019

My coworker friend, Matt, carved both this pumpkin and the one directly below for his two young children. Apparently, there is a pattern design instrument you can use to make elaborate carvings.

The other jack o' lantern that Matt carved -- and, no, it's not some weird upside down face. Rather, it's an owl-face.

Joke I heard from Chester: How is Donald Trump like a Jack O' Lantern? Both are orange on the outside, hollow on the inside, and need to be thrown away in November as they rot.

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At the outset of this entry, I would like to note that uploading pictures to Blogger has been difficult the past several days. Indeed, it isn't even possible in "Compose" mode -- the image dialogue box that pops up is simply blank -- while in HTML mode, it takes about seven or eight tries before the full box appears.

My guess is that Google is basically trying to force everyone into its latest "New Blogger" configuration -- and doing so for its own pecuniary reasons, whether or not the new configuration really is an "improvement" in whatever sense of that term.

Halloween 2019 Weather Fright …

Yesterday Thursday, Oct. 31st, Halloween 2019, featured a very stormy wallop across the region as a powerful cold frontal system swept over a broad swatch of the eastern United States.

This entry contains a series of weather-related images both from the NWS webpages and this Capital Weather Gang entry (link embedded): Halloween storms packed a punch across the Mid-Atlantic.

Summary map of severe weather warnings by type for the eastern United States on Oct 31st, 2019

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The images directly above and directly below -- both taken from above-linked CWG entry -- provide a summary / snapshot of what happened in the severe weather outbreak on Halloween 2019 …

NWS compilation of storm reports for the eastern United States by type for the October 31st, 2019

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The powerful, drenching thunderstorms were associated with a large cold front that was part of a sprawling storm system-- dubbed "Bessie" by the Weather Channel in its fall/winter/spring extratropical storm naming convention -- also brought early season snow of 4 to 8+ inches across parts of the Great Plains and back into the Colorado Rockies.

NWS high-res surface weather map analysis, 
0Z 01 Nov 2019 (8 p.m. EDT 31 Oct 2019)

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Here are a pair of NWS radar mosaic looped images that give a sense of the storm system mid-afternoon on Thursday …

Northeast U.S. Sector base reflectivity mode radar mosaic looped 1938 - 2048 UTC (3:38 p.m. - 4:48 p.m. EDT) 
31 October 2019

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Great Lakes Sector base reflectivity mode radar mosaic looped 1958 - 2108 UTC (3:58 p.m. - 5:08 p.m. EDT) 
31 October 2019

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As for the various NWS "weather products" in effect, they were manifold all day Thursday …

The full U.S. States and Territories weather map with legend as of 1833UTC (2:33 p.m. EDT) 31 Oct 2019

Just FYI, the sprawling area of dark slate blue colors represent freeze warnings -- which typically occur in these fall situations right before the growing season ends.

You can also see the last of the red flag warnings, air quality alerts, and high wind warnings in California marking the end of the most hellish part of this year's endless conflagrations out there. (I'll have more to say on that in a subsequent entry.) Note, though, that there was also a freeze warning in parts of San Bernardino County (the dark slate blue).

This particular Santa Ana event was a "cold" one -- but that doesn't mean it can't result in massive and destructive wildfires, all the more so when those fires hit civilization (as opposed to grass and trees).

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NWS Sterling (LWX) county warning area (CWA) weather advisories with legend updated 11:36 a.m. EDT Oct 31, 2019

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LWX CWA weather advisories with legend, 5:54 p.m. EDT Oct 31, 2019

Yes, that bright yellow color signifies a tornado watch. You'll note that Anne Arundel County, which was included in the tornado watch, was also under a coastal flood warning -- which supersedes a tornado watch in the NWS priority system (see full list by priority here) and so it shows up on this map.

Screenshot of the top 15 weather events and other hazards

Thankfully, the nuclear power plant, radiological hazard, and hazardous materials warnings seldom occur...

To be clear, on the NWS maps, the highest ranking priority always shows up. So, in theory, you could have simultaneously a tornado warning and a tsunami warning -- and the tsunami warning would "win out" on the map.

Oh, and the list includes a "Child Abduction Emergency" -- that gets sent out through the NWS system … Usually, those occur in Deep Red States where Trump voting divorcing white trashy couples have the worst of public-facing custody battles...


As you can see, Child Abduction Emergency ranks 96th on the list of 128 hazards -- just below Freezing Spray Advisory, Low Water Advisory, and Local Area Emergency but just above Avalanche Watch, Blizzard Watch, and Rip Current Statement.

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LWX CWA weather advisories with legend, 10:54 p.m. EDT Oct 31, 2019

This is about as many weather hazard products as you'll ever seen in effect in our part of the world at the same time.

Of note, there were tornado warnings in effect -- but not at the moment I made a screen capture of that map (which is how I save them since you can't download that whole image as shown).

I would note that the tornado watch area east of Charlottesville -- but "isolated" from the main watch -- was just a mistake on the map. That would not happen in the real world. Yes, you could have a tornado warning like that but not a tornado watch.

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NECONUS sector GOES East GeoColor satellite image, 1856Z (2:56 p.m. EDT) 31 October 31, 2019

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It was (as usual these days) unseasonably warm ahead of the frontal passage.

The KDCA high was 77F -- and it occurred at 7:29 p.m. The low of 53F occurred just 4-1/2 hours later at 11:54 p.m. Normal daily high is 64F. It was an even quicker swing at KBWI: The high of 77F occurring at 8:28 p.m. and the low of 51F at 11:59 p.m. -- just 3-1/2 hours. For KIAD, it reached 78F at 7:17 p.m. for a high and 51F for a low at 11:59 p.m.

Dew points around the time of the high temperature were 68F to 70F as the air was, not surprisingly, very "juiced up" …

Sterling (LWX) NWS radar in standard composite mode reflectivity looped 10:03 p.m. - 10.52 p.m. EDT 
October 31, 2019

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The Sterling (LWX) radar images above and below -- composite and base reflectivity modes, respectively, at about the same time -- were taken right at the height of the severe weather in the Metro D.C. and Baltimore areas.

LWX NWS radar in standard base reflectivity looped
10:15 p.m. - 10.58 p.m. EDT October 31, 2019

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On a personal note, I happened to be leaving the gym -- whence I made it three nights this week -- right at the deluge was occurring. After several minutes of waiting, I decided to head home. However, the rainwater sluicing down 14th Street across W Street NW was like a river. Had I attempted a crossing, it would have been the difference between wet shoes and bottom-of-a-pool wet shoes.

View looking along H Street NW near Lafayette Park on a rainy night, Washington, 10:20 p.m. Oct 20, 2019

I took this picture on Wednesday night when I was heading leaving Joe's restaurant.

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As a result, I was forced to walk all the way to U Street, crossing 14th Street on the south side of the intersection, and then crossing U Street again at 15th Street, in order to get home. This was as far as I had to go in order to get more level ground where the rivulets were jump-over-able.

Needless to say, the rest of me was drenched.

Speaking of rainfall, the totals from the event -- which spanned Oct 30th and 31st -- are listed below -- along with full monthly, season-to-date (STD), and year-to-date (YTD) totals to date and departures (given in parentheses) from the 1981 - 2010 NWS base period normal values.

The term "season" refers to climatological season (beginning Sept 1st) rather than astronomical fall. As you can see, the three airports received quite a bit of rain in October -- almost enough to make up for the preceding three month deficit.

KDCA
Event: 1.51" (including 1.25" on the 31st)
Oct: 6.66" +3.26" (3.40")
STD: 6.91" -0.21" (7.12")
YTD: 37.69" +4.17" (33.52")

Note 1: KDCA is well above normal YTD because of the 3+ inch deluge on July 7th.

Note 2: Last year at this time, KDCA was at 52.89" -- and on its way to a record wet year (66.28").

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KBWI
Event: 1.32" (including 0.98" on the 31st)
Oct: 6.21" +2.88" (3.33")
STD: 6.37" -0.99" (7.36")
YTD: 33.46" -1.75" (35.21")

Note 1: At this time last year, KBWI was at 57.14 -- and on its way to a record wet year (71.82").

KIAD
Event: 1.72" (including 1.35" on the 31st, which was a daily record)
Oct: 5.97" +2.72" (3.25")
STD: 6.38" -0.79" (7.17")
YTD: 36.22" +1.05" (35.17")

Note 1: At this time last year, KIAD was at 53.30" -- and on its way to a record wet year (66.74").

The weather today (Friday, Nov 1st) was sunny, gusty, cool, and fall-like lovely with highs around 54F and dew points just about 29F all day. There are actually freeze warnings in effect for the entire Metro D.C. and Baltimore areas tonight.

LWX CWA weather advisories with legend, 10:27 a.m. EDT Nov 1, 2019

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About today -- Nov 1st, 2019 -- we are "officially" in the time of the original 1982 Ridley Scott Blade Runner movie, but this is something to which I want to dedicate an enter entry (and in the context of the California wildfires).

Los Angeles, Nov 2019 nighttime street scene as shown in the 1982 movie Blade Runner … Note the name of the club: The Snake Pit.

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And that concludes this entry.

--Regulus

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