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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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