Aug 26 Saturday 2017

Tropical Report

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Sat Aug 26 2017

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Hurricane
Harvey, located over the western Gulf of Mexico.

1. A broad area of low pressure continues to produce a large area of
disorganized cloudiness and thunderstorms over southern and central
Florida and the adjacent waters. Some development is possible
through early next week while this system moves over the western
Atlantic, before it merges with a front. Regardless of development,
heavy rain and flooding is possible over portions of southern and
central Florida, and the northwestern Bahamas during the next few
days. In addition, this system is expected to cause increasing
northeast winds and rough surf along the coast of Georgia and the
Carolinas through early next week. Please refer to products from
your local weather office for more information on this system.
* Formation chance through 48 hours…low…30 percent.
* Formation chance through 5 days…medium…50 percent.

Forecaster Zelinsky

6 AM CDT POSITION AND INTENSITY UPDATE… …HARVEY WEAKENING BUT SURGE AND RAIN THREATS REMAIN…

Hurricane Hurricane Harvey Discussion Number 24
NWS National Hurricane Center Miami FL AL092017
400 AM CDT Sat Aug 26 2017

Harvey’s eye has moved inland gradually during the past few hours,
and maximum winds have decreased significantly since landfall.
Radar velocity data from the Corpus Christi NOAA Doppler radar are
showing winds as high as 90 kt at an elevation of 3000-3500 ft in
the northwestern eyewall. The advisory intensity is therefore set
at 85 kt, which could still be a little generous. Continued
weakening is expected as Harvey’s eye continues to move inland, and
maximum sustained winds are likely to fall below hurricane force
later today. A more gradual weakening trend is anticipated after
that point, and Harvey is forecast to maintain tropical storm
strength at least through day 4, especially if part of its
circulation remains over water. The updated NHC intensity forecast
continues a similar weakening trend noted in previous advisories and
is closest to the HFIP Corrected Consensus Approach (HCCA).

The initial motion has continued to decrease, and it is now
estimated to be 325/5 kt. As the steering currents around Harvey
continue to collapse, the cyclone is expected to stall or meander
inland over southeastern Texas. Only a few models show any sort of
definitive northeastward motion at the end of the forecast period,
and for the most part, the most reliable models keep Harvey over
southeastern Texas through day 5. The NHC track forecast depicts
Harvey taking a slow counterclockwise loop just inland from the
coast. This track is expected to exacerbate the potential for
catastrophic flooding from heavy rainfall at least through the
middle of next week.

Key Messages:

1. Harvey is moving farther inland over southeastern Texas and
continues to bring life-threatening storm surge, rainfall, and wind
hazards to portions of the Texas coast.

2. A Storm Surge Warning is in effect for much of the Texas coast.
Life-threatening storm surge flooding could still reach heights of 6
to 12 feet above ground level at the coast between Port Aransas and
Port O’Connor. For a depiction of areas at risk, see the Storm
Surge Watch/Warning Graphic at hurricanes.gov. Due to the slow
motion of Harvey and a prolonged period of onshore flow, water
levels will remain elevated for several days.

3. Catastrophic and life-threatening flooding is expected across the
middle and upper Texas coast from heavy rainfall of 15 to 30 inches,
with isolated amounts as high as 40 inches, through Wednesday.
Please refer to products from your local National Weather Service
office and the NOAA Weather Prediction Center for more information
on the flooding hazard.

FORECAST POSITIONS AND MAX WINDS

INIT 26/0900Z 28.5N 97.2W 85 KT 100 MPH…INLAND
12H 26/1800Z 28.8N 97.4W 70 KT 80 MPH…INLAND
24H 27/0600Z 29.0N 97.6W 50 KT 60 MPH…INLAND
36H 27/1800Z 28.7N 97.6W 45 KT 50 MPH…INLAND
48H 28/0600Z 28.5N 97.3W 40 KT 45 MPH…INLAND
72H 29/0600Z 28.3N 96.8W 35 KT 40 MPH…INLAND
96H 30/0600Z 29.0N 96.5W 35 KT 40 MPH…INLAND
120H 31/0600Z 30.0N 96.5W 30 KT 35 MPH…INLAND

$$
Forecaster Berg