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Tropical Storm Debby Forecast Discussion Number 8
2018-08-09 10:37:16| National Hurricane Center (Atlantic)
Issued at 500 AM AST Thu Aug 09 2018 444 WTNT44 KNHC 090837 TCDAT4 Tropical Storm Debby Discussion Number 8 NWS National Hurricane Center Miami FL AL042018 500 AM AST Thu Aug 09 2018 Debby is still hanging on to tropical storm status with a new burst of deep convection having recently developed just south of the low-level center. However, the cyclone's overall cloud pattern has deteriorated significantly since the previous advisory, and there are no longer any convective bands in the region where earlier 40-plus-kt ASCAT winds were observed. As a result, the initial intensity has been lowered slightly to 40 kt, which is consistent with an average of consensus current T-number and current intensity estimates of T2.5 and T3.0, respectively, from both TAFB and SAB. Debby has begun to accelerate northeastward, and the motion estimate is now 055/15 kt. A faster northeastward motion is expected as Debby gets caught up in the high-latitude westerlies ahead of a fast-moving shortwave trough. The small cyclone is forecast to open up into a surface trough by 24 h or so due to Debby moving faster than 20 kt and steady weakening of the circulation over the cold waters of the far north Atlantic. The new NHC track forecast is similar to the previous advisory and basically lies down the middle of the tightly packed guidance envelope. Although Debby has been and is forecast to continue straddling a tight SST gradient with 26+ deg C water just to the southeast and south of the center, the ingestion of drier and more stable air from the north is expected to induce gradual weakening until dissipation or absorption occurs in about 24 h. Debby could briefly become extratropical in about 18 h, followed by dissipation shortly thereafter. FORECAST POSITIONS AND MAX WINDS INIT 09/0900Z 43.6N 45.1W 40 KT 45 MPH 12H 09/1800Z 45.4N 41.4W 35 KT 40 MPH 24H 10/0600Z...DISSIPATED $$ Forecaster Stewart
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