Potential Tropical Cyclone Two Advisory Number 1
NWS National Hurricane Center Miami FL AL022019
1000 AM CDT Wed Jul 10 2019
...TROPICAL CYCLONE EXPECTED TO FORM BY THURSDAY OVER THE
NORTHERN GULF OF MEXICO...
...STORM SURGE AND TROPICAL STORM WATCHES ISSUED AND HEAVY
RAINFALL EXPECTED...
SUMMARY OF 1000 AM CDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...28.5N 86.4W
ABOUT 170 MI...270 KM ESE OF THE MOUTH OF THE MISSISSIPPI RIVER
MAXIMUM SUSTAINED WINDS...30 MPH...45 KM/H
PRESENT MOVEMENT...WSW OR 240 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1011 MB...29.86 INCHES
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
A Storm Surge Watch has been issued from the Mouth of the Pearl
River to Morgan City, Louisiana.
A Tropical Storm Watch has been issued from the Mouth of the
Mississippi River to Morgan City, Louisiana.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Storm Surge Watch is in effect for...
* Mouth of the Pearl River to Morgan City
A Tropical Storm Watch is in effect for...
* Mouth of the Mississippi River to Morgan City
A Storm Surge Watch means there is a possibility of life-
threatening inundation, from rising water moving inland from the
coastline, in the indicated locations during the next 48 hours.
For a depiction of areas at risk, please see the National Weather
Service Storm Surge Watch/Warning Graphic, available at
hurricanes.gov.
A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.
Interests elsewhere along the U.S. Gulf Coast from the Upper Texas
Coast to the Florida Panhandle should monitor the progress of this
system. Additional Tropical Storm or Hurricane watches could be
issued later today or tonight west of Morgan City.
For storm information specific to your area, including possible
inland watches and warnings, please monitor products issued by your
local National Weather Service forecast office.
DISCUSSION AND OUTLOOK
----------------------
At 1000 AM CDT (1500 UTC), the disturbance was centered near
latitude 28.5 North, longitude 86.4 West. The system is moving
toward the west-southwest near 8 mph (13 km/h). A motion toward the
west-southwest or southwest is expected through Thursday morning,
followed by a turn toward the west late Thursday and a turn
toward the west-northwest on Friday. By early Saturday, a northwest
motion is expected. On the forecast track, the system is
expected to approach the central U.S. Gulf Coast this weekend.
Maximum sustained winds are near 30 mph (45 km/h) with higher gusts.
Strengthening is forecast during the next 72 hours, and the
disturbance is forecast to become a tropical depression Thursday
morning, a tropical storm Thursday night, and a hurricane on Friday.
Shower and thunderstorm activity has gradually been increasing in
coverage and organization, and the low is likely to become a
tropical depression or a tropical storm in the next day or so.
* Formation chance through 48 hours...high...near 100 percent
* Formation chance through 5 days...high...near 100 percent
The estimated minimum central pressure is 1011 mb (29.86 inches).
HAZARDS AFFECTING LAND
----------------------
STORM SURGE: The combination of a dangerous storm surge and the
tide will cause normally dry areas near the coast to be flooded by
rising waters moving inland from the shoreline. The water could
reach the following heights above ground somewhere in the indicated
areas if the peak surge occurs at the time of high tide...
Mouth of the Pearl River to Morgan City...3 to 5 ft
Surge-related flooding depends on the relative timing of the surge
and the tidal cycle, and can vary greatly over short distances. For
information specific to your area, please see products issued by
your local National Weather Service forecast office.
RAINFALL: The system is expected to produce total rain
accumulations of 6 to 12 inches near and inland of the central Gulf
Coast through early next week, with isolated maximum rainfall
amounts of 18 inches.
WIND: Tropical storm conditions are possible within the watch
area by late Thursday or early Friday.
NEXT ADVISORY
-------------
Next intermediate advisory at 100 PM CDT.
Next complete advisory at 400 PM CDT.
$$
Forecaster Stewart
Potential Tropical Cyclone Two Discussion Number 1
NWS National Hurricane Center Miami FL AL022019
1000 AM CDT Wed Jul 10 2019
High-resolution satellite imagery along with surface and upper-air
data indicate that the broad low pressure system located over the
northeastern Gulf of Mexico has become a little better defined. The
initial intensity of 25 kt is based on an average of 1-minute wind
speeds of 20-33 kt reported by ships and buoys well south of the
poorly defined center. Although the system is currently experiencing
some northerly vertical wind shear, the shear is expected to
gradually subside over the next day or so, and the low has a high
chance of becoming a tropical depression or tropical storm by
Thursday. Since this system has the potential to bring tropical
storm conditions and storm surge to portions of the coast of
Louisiana by late Thursday or Friday, Potential Tropical Cyclone
advisories are being initiated at this time.
The initial motion estimate is an uncertain 245/07 kt. Some erratic
motion will be possible during the 24 hours or until a well-defined
center develops. However, the general motion as indicated by the
global and regional models is expected to be toward the west-
southwest or southwest. By Friday, the cyclone is forecast to turn
toward the west-northwest and then turn northwestward by Saturday
into a developing break in a deep-layer ridge that currently extends
from the southeastern U.S. westward across the southern Plains and
into the Desert Southwest. The timing of the ridge breakdown owing
to a shortwave trough moving southeastward out of the northern
Plains will be critical since a later/earlier turn by the cyclone
would shift the track west/east of the current forecast. The model
guidance is widely divergent after 48 hours with the UKMET model the
farthest west showing landfall along the Upper Texas coast, and the
GFS and HMON models farther east with landfall in south-central
Louisiana. The ECMWF model is about midway between these two
extremes, and the official track forecast leans toward that
model since it has performed well during this system's
pre-development phase. Note that forecast uncertainty for
disturbances is generally larger than for tropical cyclones,
especially beyond 48-72 hours.
Only slow strengthening is expected for the next 24-36 hours due to
the lack of a well-defined center and inner-core wind field, along
with some modest northerly wind shear. By 48 hours and beyond,
however, the combination of atmospheric and oceanic conditions
become ideal for intensification. The very low shear shear
conditions, an impressive outflow pattern forecast by all of the
global and regional models, and anomalously warm sea-surface
temperatures of 30-31C argue for quick intensification, but given
that the system is still in the formative stages, the official
intensity forecast is a little below IVCN consensus through 48
hours and trends higher toward the ECMWF-based SHIPS guidance at
72 hours.
Key Messages:
1. A tropical depression is expected to form later today or
Thursday. Conditions appear favorable for this system to strengthen
to a hurricane at it approaches the central Gulf Coast by the
weekend.
2. Dangerous storm surge is possible in portions of southeast
Louisiana, and a Storm Surge Watch has been issued for this area.
The risk for dangerous storm surge impacts also exists farther west
along the Louisiana coast into the Upper Texas coast, and additional
storm surge watches may be needed later today or tonight. Residents
in these areas should monitor the progress of this system and listen
to any advice given by local officials.
3. A Tropical Storm Watch has been issued for portions of the
Louisiana coast and additional Tropical Storm or Hurricane Watches
could be needed later today or tonight for the remainder of the
Louisiana coast and the Upper Texas Coast.
4. The system has the potential to produce very heavy rainfall along
and inland of the central Gulf Coast through early next week. For
more information, see products from your local National Weather
Service office and the NOAA Weather Prediction Center.
FORECAST POSITIONS AND MAX WINDS
INIT 10/1500Z 28.5N 86.4W 25 KT 30 MPH...POTENTIAL TROP CYCLONE
12H 11/0000Z 27.9N 87.3W 25 KT 30 MPH...POTENTIAL TROP CYCLONE
24H 11/1200Z 27.5N 88.2W 30 KT 35 MPH...TROPICAL DEPRESSION
36H 12/0000Z 27.4N 89.3W 40 KT 45 MPH
48H 12/1200Z 27.6N 90.4W 50 KT 60 MPH
72H 13/1200Z 28.7N 92.3W 75 KT 85 MPH
96H 14/1200Z 30.7N 93.0W 65 KT 75 MPH...INLAND
120H 15/1200Z 32.6N 94.1W 30 KT 35 MPH...INLAND
$$
Forecaster Stewart