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Tropical Storm GEORGETTE Forecast Discussion Number 9
2016-07-23 22:38:55| National Hurricane Center (East Pacific)
Issued at 200 PM PDT SAT JUL 23 2016 000 WTPZ43 KNHC 232038 TCDEP3 TROPICAL STORM GEORGETTE DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP082016 200 PM PDT SAT JUL 23 2016 It appears that the shear is decreasing over Georgette, with the outflow improving and the mid- and low-level centers coming into better alignment. Visible imagery suggests a ragged eye trying to develop, with a small mid-level eye noted in a 1539Z SSMIS overpass. The initial intensity is set to 60 kt based on a blend of the latest Dvorak estimates of T4.0/65 kt from TAFB and T3.5/55 kt from SAB. This is also close to the latest UW-CIMSS SATCON estimate of 61 kt. The initial 34-kt wind radii were adjusted based on data from a 1444Z pass of the RapidScat scatterometer on board the International Space Station. Georgette has 24-36 hours left before moving over SSTs below 26C, and with the shear less than 10 kt some further intensification seems likely. By 48 hours and beyond, weakening is forecast due to cooler SSTs, some increase in shear, and a drier more stable atmospheric environment. The new NHC intensity forecast is similar to the last one and is near the high end of the guidance through 36 hours, but still below the HWRF. During the weakening phase the official forecast is near or a little below IVCN and shows Georgette becoming post-tropical by the end of the forecast period. The initial motion is a little more westward (285/10), perhaps due to the low- and mid-level centers coming closer together. Georgette will be steered in the next 36 to 48 hours by a strong mid-level ridge to the north. In 2 to 3 days an upper-level low slides north of Georgette underneath the ridge, and the model guidance this cycle shows a sharper poleward turn at days 3 and 4 as Georgette feels more of a steering influence from this feature. A turn back toward the west-northwest is expected by day 5 as Georgette weakens and is steered by the low-level trade winds. The new NHC track forecast is a little south of the previous one through 48 hours due to the initial position and motion and is close to the consensus. Later in the period the track has been shifted northward, but lies on the left side of the guidance envelope near the GFS. FORECAST POSITIONS AND MAX WINDS INIT 23/2100Z 13.9N 122.3W 60 KT 70 MPH 12H 24/0600Z 14.5N 123.7W 65 KT 75 MPH 24H 24/1800Z 15.4N 125.4W 75 KT 85 MPH 36H 25/0600Z 16.4N 126.7W 75 KT 85 MPH 48H 25/1800Z 17.3N 127.8W 70 KT 80 MPH 72H 26/1800Z 18.6N 129.3W 55 KT 65 MPH 96H 27/1800Z 19.9N 131.2W 45 KT 50 MPH 120H 28/1800Z 21.3N 135.0W 35 KT 40 MPH...POST-TROPICAL $$ Forecaster Brennan
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