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