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Tropical Storm ESTELLE Forecast Discussion Number 20
2016-07-20 10:39:37| National Hurricane Center (East Pacific)
Issued at 200 AM PDT WED JUL 20 2016 000 WTPZ41 KNHC 200839 TCDEP1 TROPICAL STORM ESTELLE DISCUSSION NUMBER 20 NWS NATIONAL HURRICANE CENTER MIAMI FL EP062016 200 AM PDT WED JUL 20 2016 Other than a brief warm spot appearing within the small CDO feature around 0400Z, the overall convective structure of Estelle has changed little since the previous advisory. Recent microwave satellite data, especially a 0531Z AMSU pass, continue to indicate that the cyclone has been unable to completely close off a mid-level eye feature. The initial intensity remains 60 kt based on an average of subjective and objective intensity estimates, and the lack of a persistent, well-developed eye feature in microwave data. Estelle has made a jog to the west, and the motion estimate is now 270/10 kt. Estelle is expected to continue on a westward track for the next 12 h or so, followed by a turn toward the west-northwest by this afternoon, a motion that is forecast to continue through 48 h. By 72 h and beyond, Estelle is expected to turn northwestward and move into a trough-induced break in the subtropical ridge around 130-135W longitude. The new NHC guidance is in good agreement on this scenario, and the official forecast track lies close to the previous advisory track and the consensus model TVCN. It isn't out of the question that Estelle could still briefly reach hurricane strength this morning. However, any strengthening that might occur will be short-lived now that the cyclone is moving over sub-26C sea-surface temperatures. Although the vertical wind shear is forecast by both the GFS and ECMWF models to remain quite low, sharply decreasing SSTs and much drier mid-level air should cause Estelle to steadily weaken after 12 h. The cyclone is forecast to become a post-tropical low in 48 h when Estelle will be moving over 22C SSTs, and dissipation is expected by 120 h. The new intensity forecast is essentially just an update of the previous advisory, and closely follows the intensity consensus model IVCN. FORECAST POSITIONS AND MAX WINDS INIT 20/0900Z 19.0N 122.0W 60 KT 70 MPH 12H 20/1800Z 19.4N 124.1W 60 KT 70 MPH 24H 21/0600Z 19.9N 126.7W 55 KT 65 MPH 36H 21/1800Z 20.6N 129.4W 45 KT 50 MPH 48H 22/0600Z 21.6N 132.0W 35 KT 40 MPH...POST-TROPICAL 72H 23/0600Z 24.5N 136.7W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 24/0600Z 28.1N 140.6W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 25/0600Z...DISSIPATED $$ Forecaster Stewart
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