Active Event
NOAA Winter 2019-2020 Season Outlook – November 1, 2019
Tropical Weather Update – October 17, 2019
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Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Thu Oct 17 2019
For the North Atlantic…Caribbean Sea and the Gulf of Mexico:
1. Showers and thunderstorms associated with a broad area of low
pressure located over the southwestern Gulf of Mexico continue to
show signs of organization. Environmental conditions are expected
to be conducive for additional development, and a tropical or
subtropical storm is likely to form later today or tonight while the
system moves generally northeastward over the western Gulf of
Mexico. The low is forecast to approach the northern or
northeastern Gulf Coast on Friday or Saturday and regardless of
development, the system is likely to produce gusty winds and rough
surf over those areas. Locally heavy rainfall is also possible
across portions of the southeast U.S. late this week and this
weekend. Interests along the northern and northeastern Gulf coast
should monitor the progress of this system. For more information
about marine hazards while the low moves across the Gulf of Mexico,
see products issued by the Tropical Analysis and Forecast Branch of
the National Hurricane Center. An Air Force Reserve reconnaissance
aircraft is scheduled to investigate the system this afternoon, if
necessary.
* Formation chance through 48 hours…high…80 percent.
* Formation chance through 5 days…high…80 percent.
High Seas Forecasts issued by the National Weather Service
can be found under AWIPS header NFDHSFAT1, WMO header FZNT01
KWBC, and online at ocean.weather.gov/shtml/NFDHSFAT1.php
Offshore Waters Forecasts for the Gulf of Mexico issued by the
National Weather Service can be found under AWIPS header MIAOFFNT4,
WMO header FZNT24 KNHC, and online at
www.hurricanes.gov/text/MIAOFFNT4.shtml
Weather Outlook – Monday, October 7, 2019
Wind Fields Friday
Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Mon Oct 7 2019For the North Atlantic…Caribbean Sea and the Gulf of Mexico:
1. A non-tropical low pressure system located over the central Atlantic
Ocean between Bermuda and the Azores is producing gale-force winds
to the north of its center. Environmental conditions are forecast
to be generally conducive for the low to acquire some subtropical or
tropical characteristics during the next day or two, and this system
could become a tropical or subtropical storm on Tuesday or Wednesday
while it moves slowly westward. Upper-level winds are expected to
become unfavorable for further development by Wednesday night.
Additional information on this system can be found in High Seas
Forecasts issued by the National Weather Service.
* Formation chance through 48 hours…medium…50 percent.
* Formation chance through 5 days…medium…50 percent.
2. Showers and thunderstorms located over the western Atlantic
between the southeastern coast of the United States and Bermuda
are associated with a trough of low pressure. This system is
forecast to move northwestward and a non-tropical low pressure area
is expected to form when the system interacts with a frontal
boundary in a couple of days. The low could acquire some
subtropical characteristics later in the week while it meanders
off the east coast of the United States. Additional information on
this system can also be found in High Seas Forecasts issued by the
National Weather Service.
* Formation chance through 48 hours…low…near 0 percent.
* Formation chance through 5 days…low…30 percent.
3. A trough of low pressure extending from the Straits of Florida
northeastward across the southern Florida peninsula is producing
disorganized showers and thunderstorms. Some slight development of
this system is possible on Tuesday when it moves over the far
western Atlantic. The disturbance is forecast to merge with a
frontal boundary and developing low off the east coast of the
United States by Wednesday, and no further development is
anticipated after that time. Regardless of development, this system
is expected to produce locally heavy rainfall over portions of the
the southern Florida peninsula during the next day or so.
* Formation chance through 48 hours…low…10 percent.
* Formation chance through 5 days…low…10 percent.
High Seas Forecasts issued by the National Weather Service
can be found under AWIPS header NFDHSFAT1, WMO header FZNT01
KWBC, and online at ocean.weather.gov/shtml/NFDHSFAT1.php
Tropical Update – September 24, 2019
Tropical Storm Karen Discussion Number 9
NWS National Hurricane Center Miami FL AL122019
500 AM AST Tue Sep 24 2019
During the last pass through Karen’s center around 0430 UTC, the Air
Force reconnaissance aircraft reported some believable SFMR winds of
34-35 kt in the southeastern quadrant and an extrapolated central
pressure of 1006 mb. The 925-mb flight-level height had also
decreased by almost 20 meters in about 2 hours, an indication that
the lower pressure estimate was legitimate. Reflectivity and
velocity data from the San Juan NOAA WSR-88D Doppler radar also
enunciate that Karen’s inner-core has become better defined over
the past few hours. Satellite intensity estimates at 0600 UTC were
T2.5/35 kt from TAFB, and T2.4/34 kt and 40 kt from UW-CIMSS ADT and
SATCON, respectively. Based on the recon and satellite intensity
data, Karen has re-strengthened to tropical storm status.
The initial motion is now northward or 360/06 kt. Karen’s forecast
track hinges heavily on the future intensity and associated vertical
structure of the cyclone. The GFS, GFS-Legacy, UKMET, and HRWF
dynamical models take a much weaker and more vertically shallow
cyclone northeastward after 48 hours and either continue with that
motion through day 5 or dissipate the system. In contrast, the ECMWF
and many of its stronger ensemble members stall Karen around days
3-4 and then turn the somewhat stronger and deeper cyclone westward
to west-southwestward to the south of a building ridge. Given that
Karen is forecast to be stronger and vertically deeper than the
weaker models, the current track forecast leans more toward the
stronger ECMWF and ECMWF-Ensemble model solutions. The new NHC
forecast is to the right of the previous advisory track and slower,
especially on days 3-5, but the new track does not extend as far
east as the weaker GFS, UKMET, and HWRF models or the consensus
models that incorporate those three models.
None of the dynamical models, including the HWRF and HMON hurricane
models, show much in the way of strengthening once Karen moves
north of Puerto Rico and Virgin Islands except for the ECMWF model,
despite the very low vertical wind shear conditions that the cyclone
will be moving into by 24 hours and beyond. Given Karen’s decent
wind field and vertical structure, the expected low shear
conditions, moist mid-level environment, and SSTs of more than 29
deg C for the next 48 hours or so, forecasting at least slow but
steady strengthening seems to be quite reasonable. By days 3-5, the
mid-level environment dries out significantly, which the weaker
models seem to be keying on. However, if Karen strengthens as
currently expected, then the cyclone’s robust circulation should
be able to mix out any dry air intrusions, allowing for at least
additional modest intensification to occur in the 72-120 hour
period. The official intensity forecast is a little above the
previous advisory, and is basically an average of the weaker
dynamical models and the stronger GFS- and ECMWF-based
statistical-dynamical models Decay-SHIPS and LGEM.
Key Messages:
1. Karen is expected to bring heavy rainfall, flash floods and
mudslides to Puerto Rico and the U.S. and British Virgin Islands
today, where a tropical storm warning is in effect. The rainfall
and potential flooding will likely continue on Wednesday even as the
center of Karen moves away from Puerto Rico and the Virgin Islands.
FORECAST POSITIONS AND MAX WINDS
INIT 24/0900Z 16.8N 65.8W 35 KT 40 MPH
12H 24/1800Z 18.1N 65.9W 35 KT 40 MPH
24H 25/0600Z 20.1N 65.5W 40 KT 45 MPH
36H 25/1800Z 22.6N 64.7W 45 KT 50 MPH
48H 26/0600Z 24.6N 64.0W 50 KT 60 MPH
72H 27/0600Z 27.3N 62.7W 55 KT 65 MPH
96H 28/0600Z 28.0N 63.0W 60 KT 70 MPH
120H 29/0600Z 27.7N 65.5W 60 KT 70 MPH