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Tropical Storm Nana Discussion Number   7
NWS National Hurricane Center Miami FL       AL162020
400 PM CDT Wed Sep 02 2020

Nana continues to feel the effects of about 15 kt of northerly 
vertical shear, as the low-level center is located near the 
northern edge of the main convective mass.  Data from the last Air 
Force Reserve Hurricane Hunter Mission showed that the flight-level 
winds at 850 mb were a little lower than earlier.  However, 
incomplete SFMR data suggested surface winds near 50 kt, and the 
aircraft reported that the central pressure is near 999 mb.  The 
initial intensity is held at 50 kt, although this could be a little 
generous.
 
The initial motion is westward or 270/13 kt.  A low- to mid-level
ridge to the north of the cyclone is forecast to keep steering Nana
toward the west, or maybe just south of west, for the remainder of
the cyclone's life.  The new forecast track, which again is changed 
only slightly from the previous forecast, calls for the cyclone to 
pass north of the Bay Islands this evening, then make landfall over
central or southern Belize in about 12-18 h.  

Nana is running out of time to strengthen before landfall, and 
between that and the ongoing shear none of the intensity guidance 
forecasts it to become a hurricane before landfall.  However, any 
strong convective burst could spin up the cyclone, and since the 
bursts have been frequent today the intensity forecast calls for 
Nana to strengthen to near hurricane strength at landfall.  After 
landfall, steady weakening is expected.  Several of the global 
models now show the remnants of Nana emerging over the Gulf of 
Tehuantepec in 48-60 h.  However, these models continue to forecast 
dissipation even over water, so the forecast dissipation time is 
unchanged since the previous advisory.


KEY MESSAGES:
 
1. Nana could bring hurricane conditions and dangerous storm surge 
tonight to portions of the coast of Belize, and a hurricane warning 
is in effect. Preparations to protect life and property should be 
rushed to completion.
 
2. Tropical storm conditions are expected in the tropical storm
warning areas in Belize, the Bay Islands, Guatemala, and the 
Yucatan Peninsula of Mexico by tonight.
 
3. Heavy rainfall with isolated maximum amounts as high as 8 to 12
inches could result in flash flooding in Belize, Guatemala, and
portions of southeastern Mexico and the Yucatan Peninsula.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/2100Z 17.0N  85.9W   50 KT  60 MPH
 12H  03/0600Z 16.8N  87.8W   60 KT  70 MPH
 24H  03/1800Z 16.6N  90.1W   45 KT  50 MPH...INLAND
 36H  04/0600Z 16.4N  92.4W   30 KT  35 MPH...INLAND
 48H  04/1800Z 16.2N  94.8W   20 KT  25 MPH...POST-TROP/REMNT LOW
 60H  05/0600Z...DISSIPATED
 
$$
Forecaster Beven
 
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