[Tropical] Tropical Cyclone Discussion

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WTNT42 KNHC 130247
TCDAT2

Tropical Storm Barry Discussion Number  11
NWS National Hurricane Center Miami FL       AL022019
1000 PM CDT Fri Jul 12 2019

The overall satellite presentation of Barry has improved since this
afternoon.  The center is located closer to the main convective
mass and there has been some expansion of the cirrus outflow.  There
has also been an increase in the convective banding over the eastern
and southeastern portions of the circulation.  Both NOAA and Air
Force Reserve reconnaissance aircraft have been in the storm this
evening.  The NOAA aircraft found peak 700 mb flight-level winds of
64 kt in the southeastern quadrant, which still supports an initial
intensity of 55 kt.

Barry has been able to strengthen over the past day or so despite
northerly shear and dry mid-level air.  With the recent increase in
convection near the center and the expansion of the upper-level
outflow, it appears that the shear over the center has decreased.
As a result, the NHC intensity forecast calls for Barry to become a
hurricane before it reaches the coast of Louisiana.  Although this
is slightly above the intensity guidance, most of the dynamical
models show some modest deepening before landfall.  After the
center moves inland, steady weakening is expected and the system
is predicted to become a remnant low in about 72 hours.

Barry has been meandering over the past several hours, but the
longer term motion is 300/3 kt. The storm is expected to turn
northwestward overnight as a weakness develops in the subtropical
ridge that extends over the southeastern United States.  This should
bring the center of the storm onshore along the south-central coast
of Louisiana on Saturday. By Saturday night or early Sunday, Barry
is forecast to turn northward around the western portion of the
aforementioned ridge.  Barry or its remnants should recurve into
the mid-latitude westerlies by late Monday.  Although the guidance
envelope has shifted slightly westward again this cycle, the NHC
track is virtually unchanged and is closest to the typically
reliable GFS and ECMWF models which lie along the eastern side
of the envelope.

Key Messages:

1. There is a danger of life-threatening storm surge inundation
along the coast of southern and southeastern Louisiana, portions of
Lake Pontchartrain, and portions of coastal Mississippi where a
Storm Surge Warning is in effect. Water levels have already begun
to rise in these areas, with peak inundation expected to occur on
Saturday. The highest storm surge inundation is expected between
Intracoastal City and Shell Beach.

2. The slow movement of Barry will result in a long duration heavy
rainfall and flood threat along the central Gulf Coast, across
portions of the Lower Mississippi Valley and north into the
Tennessee Valley through the weekend into early next week. Flash
flooding and river flooding will become increasingly likely, some of
which may be life-threatening, especially across portions of
southeast Louisiana into Mississippi.

3. Hurricane conditions are expected along a portion of the coast of
Louisiana, where a Hurricane Warning is in effect. Tropical storm
conditions are expected elsewhere along much of the Louisiana coast
and inland across portions of the lower Mississippi Valley where
tropical storm warnings are in effect.


FORECAST POSITIONS AND MAX WINDS

INIT  13/0300Z 28.6N  91.0W   55 KT  65 MPH
 12H  13/1200Z 29.3N  91.5W   65 KT  75 MPH
 24H  14/0000Z 30.4N  92.1W   50 KT  60 MPH...INLAND
 36H  14/1200Z 31.5N  92.4W   35 KT  40 MPH...INLAND
 48H  15/0000Z 32.9N  92.5W   25 KT  30 MPH...INLAND
 72H  16/0000Z 35.8N  92.4W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  17/0000Z 38.7N  90.2W   15 KT  15 MPH...POST-TROP/REMNT LOW
120H  18/0000Z...DISSIPATED

$$
Forecaster Brown
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