Eastern Pacific Basin Tropical Cyclones

Tropical Storm Celia Forecast Discussion


000
WTPZ43 KNHC 171457
TCDEP3

Tropical Storm Celia Discussion Number   4
NWS National Hurricane Center Miami FL       EP032022
1000 AM CDT Fri Jun 17 2022

The satellite presentation of the system has improved somewhat this 
morning, with a well-defined band in its western semicircle and 
some deep convection persisting near and just west of the 
estimated center. Subjective intensity estimates are up to 35 kt 
from SAB and 45 kt from TAFB, while the most recent objective 
intensity estimates from UW-CIMSS were in the 40-45 kt range. There 
were also a few wind retrievals from overnight scatterometer 
imagery in the 34-36 kt range. The initial intensity has been set to 
a possibly conservative 35 kt for this advisory, upgrading Tropical 
Depression Three-E to Tropical Storm Celia.

Celia still appears to be drifting generally northward, with the 
initial motion estimated at 020/4 kt. As discussed in the prior 
advisory, the storm is currently embedded within weak steering 
currents as a result of being a small vortex embedded within a much 
broader low-level cyclonic circulation centered over Central 
America, causing Celia to drift just east of due north over the past 
12-18 hours. Possibly due to this small size, the model guidance 
does not have a good handle on the current position or structure of 
the cyclone. For example, the latest GFS run places Celia about 150 
nm west of its actual position. The latest ECMWF run was closer to 
the correct position but barely depicts Celia as a distinct entity 
within the larger gyre circulation. Even the higher-resolution 
regional hurricane models are struggling to depict this cyclone. 
Given these difficulties, the short-term track forecast is quite 
problematic, with the track guidance spread more than double the 
typical climatological value in the 24-48 hour period. Generally the 
guidance has shifted further south this cycle, when Celia is 
expected to be steered by a building mid-level ridge and perhaps 
some low-level flow enhanced by a gap wind event in the Gulf of 
Tehuantepec. The track forecast this advisory follows suit, and is 
further south than the previous advisory after 36 hours, but still 
is not as far south as the reliable consensus aids.  Given all the 
complicating factors above, this track forecast is of low 
confidence. 

The substantial uncertainty in the track forecast also applies to 
the current intensity forecast with Celia. Easterly vertical wind 
shear is already starting to increase over the system, as suggested 
by both GFS- and ECMWF- based SHIPS guidance, and is forecast to be 
above 20 kt in 24-36 hours. The GFS model, which seems to be best 
capturing Celia's current structure, quickly shears off the current 
deep convection to the east due to the increasing upper-level flow. 
In addition, current sea-surface temperatures (SSTs) under the 
cyclone are already marginal (26-27 C) and could cool further over 
the next 36 hours given Celia's slow motion. The intensity guidance 
this cycle is lower than the previous one for the first 48-72 hours, 
and only some slight additional intensification is anticipated 
before these negative factors limit Celia's intensity. Towards the 
end of the forecast period, the shear is expected to decrease and 
SSTs warm, which could provide an opportunity for the storm to began 
intensifying again. However, it is also possible the negative 
factors indicated above may result in Celia weakening or 
degenerating into a remnant low, devoid of organized convection, as 
suggested by the ECMWF solution.

Key Messages:

1. Areas of heavy rainfall are expected north of Celia's track 
across portions of far southern Mexico, Guatemala and El Salvador 
through Sunday. This rainfall may cause some instances of flash 
flooding and mudslides across the region.

2. Interests along the coasts of El Salvador, Honduras, and 
southeastern Mexico should monitor the progress of this system. 
While Celia is expected to stay offshore, any motion to the north of 
the current forecast track, or increase in size could require a 
tropical storm watch or warning for part of this area.


FORECAST POSITIONS AND MAX WINDS

INIT  17/1500Z 11.6N  89.3W   35 KT  40 MPH
 12H  18/0000Z 11.8N  89.3W   40 KT  45 MPH
 24H  18/1200Z 12.1N  89.5W   40 KT  45 MPH
 36H  19/0000Z 12.2N  90.0W   40 KT  45 MPH
 48H  19/1200Z 12.2N  90.8W   40 KT  45 MPH
 60H  20/0000Z 11.9N  92.4W   40 KT  45 MPH
 72H  20/1200Z 11.7N  94.2W   40 KT  45 MPH
 96H  21/1200Z 12.2N  98.4W   40 KT  45 MPH
120H  22/1200Z 13.0N 102.5W   50 KT  60 MPH

$$
Forecaster Papin



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