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Tropical Storm Julia Forecast Discussion

WTNT43 KNHC 071455

Tropical Storm Julia Discussion Number   5
NWS National Hurricane Center Miami FL       AL132022
1100 AM EDT Fri Oct 07 2022

Earlier this morning, a concentrated burst of deep convection with 
a high density of lightning developed near the center of the 
cyclone while it was over the Guajira Peninsula, and microwave 
imagery shows that convective banding has increased somewhat over 
the adjacent waters.  An Air Force Reserve Hurricane Hunter aircraft 
currently investigating the system so far has found maximum 925-mb 
flight-level winds of 47 kt and SFMR surface winds of 34 kt, and on 
that basis, the depression is upgraded to a 35-kt tropical storm.

Based on the latest aircraft fix, Julia is moving a bit faster 
toward the west than expected with an initial motion of 280/16 kt.  
A strong east-northeast to west-southwest oriented ridge which 
stretches into the southern Gulf of Mexico should keep Julia on a 
quick westward path during the next 48 hours.  Since the track 
guidance has sped up a bit over the past few forecast cycles, the 
official forecast now brings Julia to the coast of Nicaragua by 
Sunday morning, which is a little sooner than was previously 
forecast.  After landfall, the track guidance currently indicates 
that Julia and its remnants should remain over Central America and 
southern Mexico through Tuesday.

Stiff north-northwesterly shear (15-20 kt) is affecting Julia, and 
that can be seen in the suppression of the northern edge of the 
recent convective burst.  Shear diagnostics suggest that this shear 
should abate soon, and Julia should commence a steady strengthening 
trend during the next two days while it crosses the southwestern 
Caribbean Sea.  Julia is forecast to become a hurricane by Saturday 
evening, and the forecast peak intensity at the time of landfall in 
Nicaragua is unchanged from the previous advisory.  The official 
forecast at that time is a bit above HCCA and the IVCN consensus 
aids, but it's still below SHIPS and LGEM guidance.  The NHC 
forecast shows 72- and 96-hour remnant low points to indicate the 
expected track over Central America, but it is highly likely that 
the center will have dissipated by those times.

Key Messages:

1. Julia is forecast to strengthen into a hurricane by Saturday 
evening while it moves over the southwestern Caribbean Sea, and a 
Hurricane Warning is now in effect for San Andres, Providencia, and 
Santa Catalina Islands.  A Hurricane Watch is also now in effect for 
much of the Nicaragua coast.  Hurricane-force winds and a dangerous 
storm surge are expected in areas where the core of the system 
crosses the islands and moves onshore.

2. The risk of flash flooding continues today over portions of the 
Guajira Peninsula. The potential for life-threatening flash flooding 
and mudslides is expected to spread to portions of Central America 
this weekend.


INIT  07/1500Z 12.7N  73.1W   35 KT  40 MPH
 12H  08/0000Z 13.0N  75.5W   45 KT  50 MPH
 24H  08/1200Z 13.2N  78.7W   55 KT  65 MPH
 36H  09/0000Z 13.1N  81.3W   65 KT  75 MPH
 48H  09/1200Z 13.1N  83.6W   75 KT  85 MPH...INLAND
 60H  10/0000Z 13.6N  85.9W   45 KT  50 MPH...INLAND
 72H  10/1200Z 14.5N  88.5W   30 KT  35 MPH...POST-TROP/INLAND
 96H  11/1200Z 16.2N  93.5W   25 KT  30 MPH...POST-TROP/INLAND
120H  12/1200Z...DISSIPATED

Forecaster Berg

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