Tiny Beryl Becomes 1st Hurricane of the Season

[srainhoutx]

Hurricane Beryl Discussion Number 4
NWS National Hurricane Center Miami FL AL022018
500 AM AST Fri Jul 06 2018

Deep convection associated with the tiny tropical cyclone has
continued to become better organized overnight. An earlier AMSR2
microwave overpass showed a well-defined mid-level eye and a
pinhole eye has been apparent in the various GOES-16 satellite
channels since shortly after 0600 UTC and was most evident around
0715 UTC. Although the clarity of the eye has waxed and waned since
that time, there is enough convective organization to increase the
initial intensity to 65 kt, making Beryl the first hurricane of the
2018 Atlantic hurricane season.

The cyclone has another 18-24 hour within very low vertical wind
shear conditions and over SSTS of 26-27 degrees Celsius. These
favorable conditions suggest that the tiny hurricane is likely to
intensify further today. The NHC intensity forecast calls for
additional strengthening and is at the upper-end of the intensity
guidance, but I would not be too surprised if the compact hurricane
reaches a slightly higher peak intensity than indicated below. By
36 hours, the shear is forecast to increase to more than 15 kt, and
it is expected to be greater than 20 kt shortly after that time.
This should cause the very small tropical cyclone to quickly
weaken, however as mentioned in the Key Messages below there is
greater uncertainty than usual regarding Beryl's intensity
forecast. Although the updated NHC forecast shows Beryl
reaching the Lesser Antilles as a tropical storm it is highly
possible that the system will have degenerated into an open trough
by that time. Regardless of the system's status at 72 h, it is
likely to bring strong gusty winds and locally heavy rains to
portions of the Lesser Antilles Sunday and Monday.

The initial motion estimate remains 275/12 kt. The track guidance
is in good agreement taking Beryl west-northwestward to the
south of a deep-layer ridge over the central Atlantic. There
has been little overall change in the latest dynamical guidance and
the new NHC track forecast is similar to the previous advisory and
lies along the southern edge of the guidance envelope closest to
the latest ECMWF and HFIP correct consensus models.


Key Messages:

1. Due to its very small size, there is greater-than-usual
uncertainty in the analysis of Beryl's current intensity. Confidence
in the official intensity forecast is also much lower than normal.
Rapid changes in intensity, both up and down, that are difficult to
predict are possible during the next couple of days.

2. While Beryl is still to forecast to quickly weaken or dissipate
as a tropical cyclone on Monday before reaching the Lesser Antilles,
there will likely be some rain and wind impacts on those islands
early next week. Residents there should monitor products from their
local weather office for more information.


FORECAST POSITIONS AND MAX WINDS

INIT 06/0900Z 10.6N 45.1W 65 KT 75 MPH
12H 06/1800Z 11.0N 46.6W 75 KT 85 MPH
24H 07/0600Z 11.7N 48.6W 75 KT 85 MPH
36H 07/1800Z 12.7N 51.0W 65 KT 75 MPH
48H 08/0600Z 13.6N 54.4W 55 KT 65 MPH
72H 09/0600Z 15.4N 61.9W 45 KT 50 MPH
96H 10/0600Z...DISSIPATED

$$
Forecaster Brown