Tropical Storm Amanda

Tropical Storm Amanda Track 1900 Hours May 27 2020
Tropical Storm Amanda Track 1900 Hours May 27 2020

Tropical Storm Amanda Satellite 0900 Hours May 30 2020Tropical Storm Amanda – NWS National Hurricane Center Miami FL 400 PM CDT Sun May 31, 2020 (see video below)

Amanda has weakened quite quickly over the mountainous terrain of Guatemala this afternoon. Although a mid-level circulation is still evident in visible satellite imagery, recent surface observations suggest that the low-level circulation has dissipated over Guatemala. Therefore, this will be the final NHC advisory on this system. The remnants of Amanda are forecast to turn northwestward later tonight, and could emerge over the southern Bay of Campeche late Monday or Tuesday where new tropical cyclone development is possible. Please refer to NHC’s Atlantic basin Tropical Weather Outlooks for more details on possible tropical cyclone development in the southwestern Gulf of Mexico.

There have been reports of torrential rainfall from Amanda over portions of El Salvador and Guatemala during the past 12-24 hours. Although the system is no longer a tropical cyclone, the larger cyclonic gyre located over southeastern Mexico is likely to continue producing heavy rainfall over portions of Central America and southern Mexico during the next several days. These rains are likely to cause life-threatening flash floods and mudslides.

FORECAST POSITIONS AND MAX WINDS
 
INIT  31/2100Z 16.0N  90.0W   25 KT  30 MPH - Depression ()
 12H  01/0600Z...DISSIPATED

NWS National Hurricane Center Miami FL 400 AM CDT Sun May 31, 2020

Conventional and scatterometer satellite data indicate that the depression has once again become better organized after a brief hiatus a few hours ago. The intensity has been increased to 35 kt based on recent UW-CIMSS ADT and SATCON satellite intensity estimates of 34 kt and 38 kt, respectively. The initial motion estimate is 020/08 kt, which is based on several passive microwave and ASCAT scatterometer fixes. Amanda is embedded within the eastern periphery of a larger cyclonic gyre centered over eastern Mexico.

The cyclone is expected to remain trapped within the larger gyre for the next few days, resulting in a north-northeastward to northward motion today, followed by a much slower northwestward to westward motion on Tuesday and Wednesday, with the remnant low possibly emerging over the Bay of Campeche on days 2 and 3. The new forecast track is similar to the previous advisory through 24 hours, but additional forecast track positions were added through 72 hours due to the possibility of the system moving over the Bay of Campeche, which could result in the formation of a new tropical cyclone.

Little change in strength is expected before landfall occurs. After landfall, the cyclone is expected to rapidly weaken over the mountains of Central America. However, the large size of the circulation could still produce winds of 20-25 kt over the adjacent waters of the eastern North Pacific, Gulf of Honduras, and the Bay of Campeche for the next 2-3 days.

The main hazards from Amanda, and the larger gyre in which the cyclone is embedded, are expected to be heavy rainfall and flooding. Amanda’s slow forward motion, large size, and abundant tropical moisture could cause life-threatening flash floods and mudslides across portions of Central America and southern Mexico, and these threats will continue well after Amanda moves inland. For additional information, see products issued by your national meteorological service.

FORECAST POSITIONS AND MAX WINDS
 
INIT  31/0900Z 13.8N  90.4W   35 KT  40 MPH - Tropical Storm (WSW Buena Vista,Guatemala)
 12H  31/1800Z 15.2N  90.1W   25 KT  30 MPH - Depression (ENE Chilasco,Guatemala)
 24H  01/0600Z 17.4N  90.3W   20 KT  25 MPH - Depression (ENE Paso Caballos,Guatemala)
 36H  01/1800Z 18.7N  91.4W   20 KT  25 MPH - Depression (ENE Chacah, MX)
 48H  02/0600Z 19.0N  92.7W   20 KT  25 MPH - Depression (ENE Frontera, MX)
 60H  02/1800Z 18.8N  93.2W   20 KT  25 MPH - Depression (ENE Paraiso. MX)
 72H  03/0600Z 18.4N  93.7W   20 KT  25 MPH - Depression (WSW Barra de Tupilco, MX)
 96H  04/0600Z...DISSIPATED

NWS National Hurricane Center Miami FL 1000 PM CDT Sat May 30, 2020

Satellite imagery, including a recently-received Windsat overpass, indicates that the depression is gradually becoming better organized, with an area of stronger convection forming near the better defined center. Satellite intensity estimates at 00Z were near 25 kt, and based on the increased organization since then the initial intensity is increased to 30 kt. Some additional strengthening is possible during the next 6-12 h before landfall, and the depression could become a tropical storm during that time. After landfall, the cyclone is expected to quickly weaken and dissipate over the mountains of Central America.

The initial motion of 030/5 is somewhat uncertain. The depression is on the east side of a developing large cyclonic gyre over eastern Mexico and Central America, as well as being between the subtropical ridge and a mid-level trough over central Mexico. This combination of features should steer the cyclone north-northeastward to northward until dissipation. The new forecast track is changed little from the previous advisory and lies near the various consensus models. The main hazard from the system, and the larger gyre, is expected to be heavy rainfall. The depression’s slow forward motion, large size, and abundant tropical moisture could cause life-threatening flash floods and mudslides across portions of Central America and southern Mexico, and this threat will continue well after the depression dissipates.

FORECAST POSITIONS AND MAX WINDS
 
INIT  31/0300Z 13.0N  90.6W   30 KT  35 MPH - Depression (WSW Los Cobanos,El Salvador)
 12H  31/1200Z 14.1N  90.4W   30 KT  35 MPH - Depression (WSW Guazacapán,Guatemala)
 24H  01/0000Z 16.1N  90.2W   20 KT  25 MPH - Depression (WSW Las Pozas, Guatemala)
 36H  01/1200Z...DISSIPATED

NWS National Hurricane Center Miami 400 PM CDT Sat May 30, 2020

Satellite data indicate that the low-pressure system that NHC has been monitoring near the coasts of Guatemala and El Salvador has developed sufficiently organized deep convection and a well-defined center to be classified a tropical depression. It should be noted that this depression is embedded within a large gyre that is spread out across the far eastern Pacific and portions of Central America. The initial intensity is set at 25 kt, following the maximum wind observed in recent ASCAT passes and a Dvorak classification from TAFB. The depression could strengthen a little before it reaches the coast of Guatemala early Sunday, but significant strengthening is not expected given the broad structure of the cyclone and its limited time over water. A tropical storm warning has been issued by the governments of Guatemala and El Salvador for the entire coastline of those countries.

The initial motion of the depression is estimated to be 030/3 kt, but this is highly uncertain given that the center of the system has only recently become well defined. The track models are in fairly good agreement that a slow northward or north-northeastward should occur through landfall, and the cyclone is expected to dissipate over the rugged terrain of Guatemala late Sunday or Sunday night.

The main hazard from the system, and the larger gyre, is expected to be heavy rainfall. The depression’s slow forward motion, large size, and abundant tropical moisture could cause life-threatening flash floods and mudslides across portions of Central America and southern Mexico. For additional information, see products issued by your national meteorological service.

FORECAST POSITIONS AND MAX WINDS

INIT 30/2100Z 12.3N 91.1W 25 KT 30 MPH
12H 31/0600Z 13.2N 90.9W 30 KT 35 MPH
24H 31/1800Z 15.0N 90.5W 25 KT 30 MPH…INLAND
36H 01/0600Z…DISSIPATED

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Video: Tropical Storm Amanda Brings Severe Floods and Winds to El Salvador – May 31, 2020