[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT45 KNHC 021505
TCDAT5

Hurricane Elsa Discussion Number   9
NWS National Hurricane Center Miami FL       AL052021
1100 AM AST Fri Jul 02 2021

Satellite imagery indicates that Elsa has become better organized,
and radar data from Barbados and Martinique have shown attempts at
eye formation.  The formative northern eyewall passed over Barbados
near 11-12Z, and hurricane-force winds were reported there at that
time. The initial intensity is set at 65 kt based on those data. It
should be noted that reports from an Air Force Reserve Hurricane
Hunter aircraft suggest that the circulation is not well-developed
at 700 mb, possible due to the rapid forward speed.

The initial motion is 290/25.  There is little change to the
forecast track or the forecast guidance since the last advisory.
The guidance is in good agreement on a rapid west-northwestward
notion to near the south coast of the Dominican Republic by 36 hr.
After that, the general consensus is that Elsa should turn northward
by 96 h through a weakness in the subtropical ridge created by a
mid-latitude trough.  However, the guidance is quite divergent
around this consensus, with possible tracks ranging from a
west-northwestward motion through the Yucatan Channel or western
Cuba to a northward motion through the Bahamas.  Thus, the latter
portion of the track forecast remains low confidence.

The intensity forecast calls for a little more strengthening during
the next 36 h as Elsa moves through an environment of light
westerly shear.  After that, land interaction, along with less
favorable upper-level winds over the Gulf of Mexico, is likely to
cause weakening.  The new NHC intensity forecast shows major
adjustments from the previous forecasts based primarily on the
initial intensity.

It should be noted that the average NHC track errors are 175 miles
and 200 miles at days 4 and 5, respectively.  Given the
larger-than-normal uncertainty and because hazards will extend well
away from the center of the storm, users are urged to not focus on
the exact forecast points.

Key Messages:

1. Hurricane conditions are expected in the Hurricane Warning area
in the Windward Islands for the next few hours.  Tropical storm
conditions are expected in other portions of the Windward and
Leeward Islands. Hurricane conditions are expected in the Hurricane
Warning area in Haiti on Saturday. Tropical storm conditions are
expected with hurricane conditions possible along the southern
coast of the Dominican Republic and in Jamaica.

2. Heavy rainfall from Elsa will move quickly across the Windward
and southern Leeward Islands today, including Barbados. Outer rain
bands will impact Puerto Rico late today into Saturday, and southern
Hispaniola and Jamaica Saturday into Sunday. Flooding and mudslides
are possible.

3. There is an increasing risk of strong winds, storm surge and
rainfall impacts in portions of Cuba this weekend and early next
week, with impacts also possible in the Turks and Caicos and
the Bahamas. Interests in these areas should monitor Elsa's
progress and updates to the forecast.

4. There is a risk of storm surge, wind, and rainfall impacts in the
Florida Keys and portions of the Florida Peninsula early next week.
However, the forecast uncertainty remains larger than usual due to
Elsa's potential interaction with the Greater Antilles this weekend.
Interests in Florida should monitor Elsa's progress and updates to
the forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  02/1500Z 13.4N  61.2W   65 KT  75 MPH
 12H  03/0000Z 14.6N  64.9W   70 KT  80 MPH
 24H  03/1200Z 16.3N  69.8W   70 KT  80 MPH
 36H  04/0000Z 17.8N  73.6W   70 KT  80 MPH
 48H  04/1200Z 19.3N  76.4W   65 KT  75 MPH
 60H  05/0000Z 20.7N  78.4W   55 KT  65 MPH
 72H  05/1200Z 22.1N  80.5W   55 KT  65 MPH...INLAND
 96H  06/1200Z 26.0N  82.5W   55 KT  65 MPH...OVER WATER
120H  07/1200Z 30.6N  81.5W   40 KT  45 MPH...INLAND

$$
Forecaster Beven
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