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Tropical Storm Kiko Forecast Discussion Number 4
2019-09-13 10:52:19| National Hurricane Center (East Pacific)
Issued at 300 AM MDT Fri Sep 13 2019 000 WTPZ43 KNHC 130852 TCDEP3 Tropical Storm Kiko Discussion Number 4 NWS National Hurricane Center Miami FL EP132019 300 AM MDT Fri Sep 13 2019 Kiko's convective pattern has still not gotten any better organized. There's a small patch of convection near the estimated center, with another larger cluster much farther south. For the most part, however, the circulation consists of a broken low- and mid-level cloud deck with a few embedded showers. Subjective Dvorak estimates from TAFB and SAB are T2.0/30 kt, while objective numbers are only slightly higher. The initial intensity is being held at 35 kt, but it's entirely possible that Kiko may not be producing tropical-storm-force winds at this time. The GOES-17 air mass product shows that Kiko is surrounded by some of the driest air over the entire tropical eastern Pacific, which could be contributing to the system's convective struggles. And going forward, it appears that the thermodynamic environment could be less than ideal for significant strengthening, with SHIPS model diagnostics showing environmental stability to be the biggest negative factor. That being said, vertical shear is expected to be less than 10 kt for at least the next 3 days, so strengthening is likely if the dry air can be mixed out of the circulation. The new NHC forecast continues to show Kiko reaching hurricane strength in about 48 hours, although the peak intensity has been tempered a bit based on the latest guidance. The official forecast is close to a blend of the Florida State Superensemble and the HFIP Corrected Consensus aids. Kiko is moving west-northwestward, or 295/9 kt, to the south of a mid-level ridge which extends along the U.S./Mexico border. This motion should continue for the next 3 days, and the track models are in good agreement on this solution. After day 3, there is a bifurcation of the models, with the GFS, HMON, COAMPS-TC, and Canadian turning Kiko northwestward or northward into a break in the ridge, and the ECMWF, UKMET, HWRF, and the consensus aids maintaining a west-northwestward or even westward heading on days 4 and 5. Due to this divergence, the updated forecast shows a slightly slower motion toward the end of the forecast period, but the track itself is very similar to the previous forecast, lying near the northern boundary of the southern camp of models. FORECAST POSITIONS AND MAX WINDS INIT 13/0900Z 16.8N 113.5W 35 KT 40 MPH 12H 13/1800Z 17.1N 114.9W 40 KT 45 MPH 24H 14/0600Z 17.5N 116.6W 50 KT 60 MPH 36H 14/1800Z 17.9N 118.3W 60 KT 70 MPH 48H 15/0600Z 18.4N 120.0W 65 KT 75 MPH 72H 16/0600Z 19.4N 123.1W 65 KT 75 MPH 96H 17/0600Z 20.5N 125.5W 45 KT 50 MPH 120H 18/0600Z 21.0N 127.5W 35 KT 40 MPH $$ Forecaster Berg
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