je.st
news
Tropical Storm Marie Forecast Discussion Number 6
2020-09-30 16:43:41| National Hurricane Center (East Pacific)
Issued at 900 AM MDT Wed Sep 30 2020 000 WTPZ43 KNHC 301443 TCDEP3 Tropical Storm Marie Discussion Number 6 NWS National Hurricane Center Miami FL EP182020 900 AM MDT Wed Sep 30 2020 Marie's satellite presentation has been gradually improving. The center is embedded beneath a central dense overcast feature, and the convective band within the western semicircle has become a little more pronounced and continuous. In addition, a mid-level eye has begun to form, as observed in a 1200 UTC SSMIS microwave pass. Dvorak intensity estimates range from 45-55 kt from TAFB and SAB, and the most recent SATCON estimate was 53 kt (at around 0900 UTC). Based on these numbers and the continued improvement of Marie's structure, the initial intensity is set at 55 kt. The stage appears set for Marie to rapidly intensify during the next couple of days. Water vapor imagery indicates that the easterly shear over the cyclone has continued to decrease and should be generally low for the next 3 days, and upper-level divergence will also be in place during that period to help ventilate the storm. The thermodynamics are also favorable for fast strengthening, highlighted by sea surface temperatures of 28-29 degrees Celsius and plenty of moisture in the surrounding environment. Due to these conditions, the NHC forecast explicitly shows rapid intensification during the next couple of days, with a peak intensity likely occuring sometime between 48 and 60 hours. The peak intensity shown in the official forecast has been nudged upward slightly from the previous prediction, following the trends in the intensity guidance, however it's noteworthy that even this forecast is 5-10 kt lower than the solutions provided by the HCCA consensus aid and the COAMPS-TC model. In about 3 days, cooler waters and then increasing shear (especially on days 4 and 5) should induce a gradual weakening trend. Marie is moving westward (275/14 kt) to the south of a strong mid-tropospheric high centered near the U.S./Mexico border. This ridge is expected to maintain Marie on a westward or west-northwestward trajectory for the next 2-3 days. Even though a mid- to upper-level low near 130W longitude has caused a break in the ridge, the models have trended toward this feature weakening during the next few days. This has in turn caused many of the models to trend westward with Marie's track after day 3, as was noted in the previous advisory, but there is also greater spread than there was yesterday. The NHC track forecast remains closest to the TVCE and HCCA consensus aids, near the middle of the guidance envelope, which is bracketed on the right side by the GFS (and its ensemble mean) and the left side by the ECMWF (and its ensemble mean) by the end of the forecast period. The 12-ft sea radii remain larger than would be expected for a tropical storm of Marie's size due to a large fetch of southerly swell originating from the Southern Hemisphere. FORECAST POSITIONS AND MAX WINDS INIT 30/1500Z 14.2N 113.8W 55 KT 65 MPH 12H 01/0000Z 14.3N 116.1W 65 KT 75 MPH 24H 01/1200Z 14.5N 118.9W 85 KT 100 MPH 36H 02/0000Z 15.1N 121.5W 100 KT 115 MPH 48H 02/1200Z 15.9N 123.9W 110 KT 125 MPH 60H 03/0000Z 16.9N 125.9W 115 KT 130 MPH 72H 03/1200Z 18.0N 127.6W 100 KT 115 MPH 96H 04/1200Z 19.8N 130.7W 75 KT 85 MPH 120H 05/1200Z 21.1N 133.4W 55 KT 65 MPH $$ Forecaster Berg
Tags: number
discussion
marie
storm
Category:Transportation and Logistics
Latest from this category |
All news |
||||||||||||||||||
|
|||||||||||||||||||