Month: October 2017

2017 Sixteen - 10/4 Data Dump

Click on map to see latest

As with all forecast, there are some limiting factors for accuracy. All I can do is tell you what I see in the data.

  • Rapid intensification in the next three days, approaching category 2, but disrupted by the storm passing over the two landmasses containing Honduras and the Yucatan. This track impedes accurate intensity forecast.
  • Steering currents should be predictable when it gets into the Gulf of Mexico.  (potentially within the next 24-48 hours, they should form). This will allow a track forecast to be produced with a decent amount of accuracy.
  • Currently looking like the re-curve will initially head for Terrebonne Parish but then turn towards the western-most part of the Florida Panhandle.

PLEASE NOTE: It is way to early to bet life and property on a forecast of this storm.  Unfortunately, a decent forecast is impossible until it passes over the Yucatan, which gives a minimum amount of time to prepare.  Please, maintain a level of awareness of this storm over the next few days.

Water Vapor
From NHC 4 pm CST 10/4/2017
Satellite

000
WTNT41 KNHC 042051
TCDAT1

Tropical Depression Sixteen Discussion Number 2
NWS National Hurricane Center Miami FL AL162017
500 PM EDT Wed Oct 04 2017

Visible satellite images show that the depression has lots of
curved bands, although it is somewhat lacking any inner core
features. An Air Force Reserve Hurricane Hunter flew into the
depression this afternoon and found a well-defined circulation, with
maximum flight-level winds of 37 kt and SFMR values around 30 kt.
These data support keeping the intensity at 30 kt for this advisory.

Environmental conditions look quite favorable for strengthening over
the next few days, with low shear and very warm and deep water in
the path of the cyclone. The various rapid intensification indices
are all higher than the last cycle, suggesting an increasing chance
of rapid intensification occurring. The fly in the ointment,
however, is all of the potential land interaction, first over
Central America and then possibly over the Yucatan Peninsula. As
a compromise, the intensity forecast is raised considerably from the
previous one during the first 3 days, but is still below some
guidance, such as the HWRF.

The depression continues to move slowly northwestward, steered by a
distant ridge over the southwestern Atlantic. However the steering
pattern is forecast to change quickly tomorrow as a mid-tropospheric
trough over the Florida Straits moves across the northwestern
Caribbean into the southwestern Gulf of Mexico. Southerly flow on
the eastern side of that trough should cause the cyclone to move
much faster to the north-northwest by Friday and northward into the
Gulf of Mexico on Saturday. While there is some agreement on the
synoptic pattern, the model track agreement is rather poor, even in
the short term, with the GFS and ECMWF being 90 miles apart on the
forecast track as soon as 24 hours out. This has profound
differences down the road, with the GFS-based guidance moving
considerably faster and to the left of the ECMWF and UKMET across
the Gulf of Mexico. Overall, the guidance has generally shifted a
bit westward since the last cycle, so the latest points in the long
range have been adjusted in that direction. At this point, I
wouldn't focus too much attention on the details of the long-range
forecast until the guidance comes into better agreement. A G-IV
mission and Florida special soundings have been set up for tomorrow
to better determine the synoptic steering flow around the cyclone.

KEY MESSAGES:

1. The depression is forecast to strengthen and bring tropical storm
conditions to portions of Nicaragua and Honduras tonight through
Friday. Heavy rainfall could produce life-threatening flash
flooding and mud slides in portions of Nicaragua, Honduras, Costa
Rica, and Panama through Friday night.

2. The system is expected to be near hurricane intensity when it
approaches the Yucatan Peninsula late Friday or Saturday, bringing
direct impacts from wind, storm surge, and heavy rainfall. A
hurricane watch could be issued for this area later this evening.

3. The system is forecast to continue strengthening over the Gulf of
Mexico and could affect portions of the northern Gulf Coast as a
hurricane this weekend, with direct impacts from wind, storm surge,
and heavy rainfall. However, it is too early to specify the timing,
location, or magnitude of these impacts. Residents along the Gulf
Coast from Louisiana to Florida should monitor the progress of this
system for the next several days and heed any advice given by local
officials.

FORECAST POSITIONS AND MAX WINDS

INIT 04/2100Z 12.5N 82.5W 30 KT 35 MPH
12H 05/0600Z 13.2N 83.1W 40 KT 45 MPH
24H 05/1800Z 14.6N 83.8W 40 KT 45 MPH...INLAND
36H 06/0600Z 16.7N 84.6W 50 KT 60 MPH
48H 06/1800Z 19.5N 85.8W 60 KT 70 MPH
72H 07/1800Z 25.0N 88.0W 75 KT 85 MPH
96H 08/1800Z 30.5N 86.0W 65 KT 75 MPH...INLAND
120H 09/1800Z 35.5N 82.0W 30 KT 35 MPH...POST-TROP/INLAND

$$
Forecaster Blake

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Oct. 4, 2017, Thoughts and Focus

Data is starting to congeal.  Initial projections are looking like it will be heading to Alabama.   The probability of development is now at 90% for the next 24-48 hours.

I'm interested in what the strength potential will be. The Gulf is 4°F above the average temp, there are gale-force winds and 12 ft. seas.  The GOM is angry.  This indicates a lot of energy is available for rapid development once the area crosses the Yucatan.

My intuition tells me that this could be a category 1 or 2 at landfall to the east of the mouth of the Mississippi River.   However, this prediction could radically change within the next 48 hours.

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