Hurricane Maria Live Thread

NHC/NOAA ^ | 9/16/2017 | NHC/NOAA

[NautiNurse]

Hurricane Jose has been hanging around, waiting for attention in the wake of Hurricane Irma. Newcomer Maria threatens to impact the Caribbean Islands already devastated by Hurricane Irma, and brushed by Jose. Hurricane Jose threatens to brush or impact New England. Lee appears to be a fish storm at this time.

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Jose	Maria
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Public Advisories	Public Advisories
Forecast Discussions	Forecast Discussions

[houeto]

Good Lord! That is 193 mph!!!

[Paul R.]

Yikes!

That (and the Andrew recollection — I wasn’t there but had friends in the immediate area) brings up an interesting point: It is sometimes argued that a small intense storm is “better” than a larger storm with lower winds, because the damage total from the larger storm is higher. I can see that from a $$ standpoint: A lot of partially damaged structures over a large area might still require a complete or very extensive rebuild. (I can still “see” the two “wavy” outside walls that stayed up in our home that was hit by a tornado — we just tore what remained, down.)

However, it is “probable” to survive in a home that has heavy damage, but not complete destruction. That’s the whole “inner room” bit. OTOH, if many structures are obliterated, with people still in them, I would think the death toll would be higher in the smaller intense storm, even though the number of structures needing to be rebuilt would be higher in the less intense storm. Does history bear this out, I wonder? Or does the widespread flooding associated with many large storms zap that analysis?

Katrina might seem to support the latter argument, but then again, with that levee situation, perhaps it was an outlier in terms of number of deaths. Or, put another way, what if an “Andrew” had KO’d New Orleans? Hmmm...

[dfwgator]

Ugggh, it just jogged more to the north, Frederiksted might get clipped afterall.

[jeffers]

0046EDT. I'm seeing "pure annular."



That spiral connecting band is detailed in the here, and structurally, there's just not much to it. The section indicated by the orange arrow has essentially zero convection visible, while the section indicated by the black arrow has the barest return at the 25 to 28 dBz level, from red arrow to red arrow.

Time and trend will tell, but I think we've seen the end of the inner eyewall, and perhaps, peak intensity.

[Paul R.]

ZCZC MIATCDAT5 ALL
TTAA00 KNHC DDHHMM

Hurricane Maria Discussion Number 16
NWS National Hurricane Center Miami FL AL152017
1100 PM AST Tue Sep 19 2017

Since the previous advisory, WSR-88D radar data from San Juan
Puerto Rico has shown the development of concentric eyewalls and
a double-wind maximum. This has led to an increase in the size of
the 50- and 64-kt wind radii. An earlier Air Force Reserve
reconnaissance aircraft measured a peak flight-level wind of 157 kt
and a few SFMR winds of 149-152 kt in the small inner eyewall
between 2200 and 0000 UTC this evening. Based on these data, the
initial wind speed was increased to 150 kt. The minimum pressure
estimated from earlier dropsonde data is 909 mb, which is the tenth
lowest minimum pressure recorded in an Atlantic basin hurricane.
Since the outer eyewall has become better defined and the winds are
increasing within the outer eyewall, it is likely that Maria’s
intensification will finally cease. However, Maria is expected to
remain an extremely dangerous category 5 hurricane until landfall in
Puerto Rico early Wednesday. The passage of the core over Puerto
Rico should cause some weakening, but Maria is likely to remain a
major hurricane for several more days. Increasing shear and cooler
waters over the western Atlantic in the wake of hurricanes Irma and
Jose will likely lead to additional weakening late in the period.

Maria is moving between west-northwest and northwest at about 9 kt.
A weak ridge over the western Atlantic is expected to steer the
hurricane on this general heading over the next couple of days.
This track will bring the center of Maria over Puerto Rico and just
north of the eastern Dominican Republic over the next day or so.
After that time, a break in the ridge should cause Maria to turn
north-northwestward, then northward by late in the week. The track
guidance is tightly clustered through 72 hours, yielding fairly high
confidence in the track forecast through that time. There is some
increase in the spread of the models at days 4 and 5, with the GFS
and HWRF farther west and faster, while the ECMWF is along the
eastern edge of the guidance and slow. For now, the NHC track
forecast is between the various consensus models at 96 and 120 h.

KEY MESSAGES:

1. Maria’s core will pass near or over St. Croix within the next
few hours and will approach the southeastern coast of Puerto Rico
early Wednesday, bringing life-threatening wind, storm surge, and
rainfall impacts to portions of those islands. Everyone in these
areas should follow advice from local officials to avoid
life-threatening flooding from storm surge and rainfall.

2. Wind speeds atop and on the windward sides of hills and mountains
and on high-rise buildings could be much stronger than the
near-surface winds indicated in this advisory.

3. A Hurricane Warning is also in effect for the remainder of the
Virgin Islands and the northern coast of the Dominican Republic,
where Maria is expected to bring dangerous wind, storm surge, and
heavy rainfall.

4. A Hurricane Watch is in effect for the southeastern Bahamas and
the Turks and Caicos, where Maria could bring hurricane conditions
on Thursday.

FORECAST POSITIONS AND MAX WINDS

INIT 20/0300Z 17.3N 64.7W 150 KT 175 MPH
12H 20/1200Z 18.0N 65.8W 145 KT 165 MPH
24H 21/0000Z 18.9N 67.3W 125 KT 145 MPH
36H 21/1200Z 19.9N 68.6W 120 KT 140 MPH
48H 22/0000Z 20.9N 69.7W 115 KT 130 MPH
72H 23/0000Z 23.3N 71.4W 110 KT 125 MPH
96H 24/0000Z 26.2N 72.2W 105 KT 120 MPH
120H 25/0000Z 29.5N 72.5W 90 KT 105 MPH

$$
Forecaster Brown

[dfwgator]

I pray you’re right.

[Paul R.]

Yes, also see my post of NHC’s latest...

[Paul R.]

the winds are increasing within the outer eyewall,

St. Croix won't appreciate that.

[jeffers]

Later core data, from 0038 EDT:



Data box indicates the take when the arrowed location was in the inner eyewall. That's the peak values for this run, which doesn't include the NE Quadrant.

He's on an outbound leg now, just leaving the outer precip band at 135 degrees, on the SE side.

[jeffers]

Latest, maybe 9 minutes out of realtime:

[MeneMeneTekelUpharsin]

What is the latest pressure in MB?

[jeffers]

Right now, east end of St. Croix, showing velocities with radial components of around 30 knots at 10k feet ASL. (Blue arrow)



At the PR coastline, (black arrow), radial component velocities at 52 knots and change, around 1000 feet ASL.

Same Hurricane Hunter now visible (here) at 90 degrees storm relative. Measuring 72 knots at 65 NM from eye center. That's a 150 mile diameter Hurricane Force Wind zone.

[jeffers]

Official pressure has been 909 mb for a while, but there are reports here as low as 906 mb.

[Impy]

Be safe!

[MeneMeneTekelUpharsin]

Thx

[jeffers]

Directional plot, using postions from 52 minutes ago and current:

[dfwgator]

Looking at the map, the Sandy Point Wildlife Refuge got nailed. Hopefully in the city of Frederiksted they somehow avoided the absolute worst part of the eye wall. Every mile away from that eye wall is huge.

[jeffers]

Coupla bits of info here:



One, the Hurricane Hunter has turned back towards the core, looks like we're going to get another pass thru the NE Quad.

Two, on this particular radar plot, the NROT derivative data looks to highlight potential tornadic shear, (yellow arrows), as evidenced by the twin Tornado Vortex Signatures at the lower left arrow.

[jeffers]

Agreed. It’s more evident on the Storm Relative Velocity plot than it is on Base Velocity posted above, but that outer eyewall just doen’t have the windspeed that the inner one does.

I think that trend is changing though. With HF winds at 75 miles radius now, and the one bouy readout I found between eyewall and PR, of 82 degrees F, it won’t get weaker overall, and conservation of energy means anything the inner eyewall loses, has to go somewhere, whether it strengthens or not.

[jeffers]

Hurricane Hunter inbound at the red arrowhead. White line indicates his intended course, but keep in mind the hurricane is moving too. We still should get some good data from both the inner and outer eyewalls.