re: Tropical Storm Nicholas - Flash Flood Watch for South Louisiana

Looking at radar that SW shear and dry air are definitely keeping heavier rain bands in check. Should be manageable rain event for most

Someone else commented on it, but I was amazed at the complete lack of lightning and thunder from the storm.

If I lived in a world with no cable and Internet, I wouldn’t have suspected a thing.

Around Washington Ave/Montrose/Heights, I never lost power, one friend did for an hour or so in the middle of the night, two others (in the heights) still without power.

I would say 85 percent of my team at work has power (pretty evenly distributed around the city).

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Colonial Pipeline has shut down its two main pipelines, Line 1 and Line 2, leading out of the refinery-heavy U.S. Gulf Coast sector, according to a shipper bulletin sent just before 10:00 a.m. ET Tuesday morning.

Line 1 carries gasoline products while Line 2 transports distillate material.

The bulletin said the lines were "proactively" shut down early Tuesday morning due to "power outage[s] in the Houston-area following the landfall of Hurricane Nicholas."

North of the Gulf Coast, Colonial Pipeline said Line 3 and Line 4, which move material north from Greensboro, North Carolina, along the northeast U.S., were still operating normally.

Typically, any extended downtime of the two main lines out of the Gulf Coast will back up material there and send prices lower as excess material is sold off in the spot market. Inversely, Northeastern markets will see prices start to rise if resupply to the region is stymied.

The shutdown today marks the second time in the last few weeks where both main Colonial Pipeline throughfares out of the Gulf Coast region have been stopped.
On Aug. 29, Colonial shut down both lines due to the impact of Hurricane Ida but restarted the southern portion of their system a few days later.

So far in the spot markets, impact has been muted with both Gulf Coast and New York Harbor markets quiet and following futures higher. Gasoline spot prices across the board were seeing gains around 1.50cts while distillate advances lagged with advances of around a half penny.

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Mesoscale Precipitation Discussion 0965
NWS Weather Prediction Center College Park MD
1001 AM EDT Tue Sep 14 2021

Areas affected...Upper Texas Coast, Southern Louisiana

Concerning...Heavy rainfall...Flash flooding likely

Valid 141359Z - 141900Z

Summary...Heavy rainfall associated with Tropical Storm Nicholas
will continue to expand and train across the Upper Texas Coast and
into much of southern Louisiana. Rainfall rates of 1-3"/hr are
likely, which through training may produce 2-5" of rain with local
amounts in excess of 5". Flash flooding is likely.

Discussion...Tropical Storm Nicholas was located at 1200 UTC to be
about 15 miles SSW of Houston, Texas moving NNE at 8 mph. The
center of circulation is still well defined on radar, with a sharp
rainfall cutoff from east to west. Nearly all of the heavy rain
evident on radar is east and northeast of the center, with recent
radar estimated rainfall rates from KLCH and KHGX of 1-2"/hr, and
this is subtly less than earlier. Recent rainfall reports have
been as high as 2-3" in the past 3 hours near Port Arthur, TX.

There appear to be two primary axes of heaviest rainfall, and this
may continue through the aftn. The first is along a potent inflow
band rotating onshore just east of the center of circulation. This
band is clearly evident on GOES-E IR imagery as rapidly cooling
cloud tops extending southwest across the Gulf of Mexico as far as
Tamaulipas, Mexico. This is occurring within a plume of higher PWs
of 2.25-2.5" noted via the Blended TPW product, and within pinched
higher SFC-850mb and 850-700mb PW surging northward on the CIRA
LPW product. This plume is also coincident with a ribbon of
greater instability analyzed by the RAP to be MLCape greater than
1500 J/kg. Despite expected slow weakening of Nicholas, the
eastward motion of the system will drive higher 850mb winds of
30-45 kts which will become nearly 1.5x the mean 850-300mb winds,
with moderate directional convergence continuing. This enhanced
ascent within the region of favorable thermodynamics should allow
this band to persist and lift northward, spreading heavy rainfall
onshore the Upper Texas coast and SW Louisiana through this aftn.
Instability should wane with latitudinal gain, so the heaviest
rain is likely along the immediate coast. Here, rainfall of 2-4"
is likely with local amounts above 5" as shown by HREF
probabilities, and flash flooding is likely.

A secondary maximum of rainfall is likely along the coast of
Louisiana from near Lake Charles to New Orleans. A convergent axis
noted in the 925-850mb wind field is acting as an effective front
at the leading edge of WAA east of Nicholas. Within this warm
sector, persistent S/SE inflow will isentropically ascend the
boundary to drive enhanced ascent within a region of PWs above
2.25" and MLCape 500-1000 J/kg. Rain rates here are likely to be
1-2"/hr, with subtle enhancement possible as the low-level flow
backs in advance of Nicholas to become more orthogonal to this
boundary. Additionally, despite fast moving individual cells,
propagation vectors are forecast to become increasingly opposed to
the mean flow suggesting backbuilding into the instability to
produce training of echoes and these rain rates. The high-res CAMs
and HREF probabilities suggest rainfall across south central and
southeast Louisiana is likely to reach 1-3" with locally higher
amounts, which is also likely to produce flash flooding into the
aftn.

Depending on the track of Nicholas, both this inflow band and its
associated extreme thermodynamics, and the effective front itself,
may lift northward this aftn. This will almost certainly
necessitate additional MPDs, possibly extending further north and
east as well.

Weiss

sticky

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it is currently raining sideways in BR

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Must be a band in your area because in downtown it has just been misting the last 3 hours or so.

Yeah she is looking fresh

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sticky

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Nicholas

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TD weather Gods, my father in law is inquiring how much rain he should expect in New Roads