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Hurricane Jerry Forecast Discussion Number 13
2019-09-20 16:57:46| National Hurricane Center (Atlantic)
Issued at 1100 AM AST Fri Sep 20 2019 000 WTNT45 KNHC 201457 TCDAT5 Hurricane Jerry Discussion Number 13 NWS National Hurricane Center Miami FL AL102019 1100 AM AST Fri Sep 20 2019 Data from both NOAA and Air Force Reserve Hurricane Hunter aircraft indicate that Jerry is weakening quickly, and radar images from NOAA show no sign of the eyewall reported on the last mission. Maximum flight-level winds on the mission were about 78 kt, with SFMR values near 70 kt, and the central pressure has risen about 10 mb overnight. These observations also agree with the latest satellite imagery that shows a less organized cyclone, with the center on the far northwestern edge of a distorted central dense overcast. A blend of all these data gives an initial wind speed estimate of 75 kt. Jerry is moving about the same as before, west-northwestward at 15 kt. The hurricane should gradually bend to the right and slow down during the next few days while the cyclone is steered around the western periphery of a weakening subtropical ridge. The guidance is tightly packed on the forecast through Monday, and little change was made to the previous NHC prediction. At longer range, a mid-latitude trough interaction should turn the hurricane northward and northeastward, but the models are really struggling on how quickly this occurs. While yesterday much of the guidance had Jerry accelerating ahead of the trough, today's models have slowed everything down as the trough looks like it could weaken before fully recurving the cyclone. The new track forecast is considerably slower than the last one beyond 72 hours, about as much as continuity allows, and later forecasts could slow Jerry down even more. Northwesterly shear is forecast to persist near Jerry for the next day or two, and some weakening is expected. The intensity forecast is reduced from the previous one, and could be a bit too high in the short term given recent trends. In a few days, the aforementioned trough interaction is anticipated, but it is next to impossible to know at this lead time whether the trough will weaken or strengthen the cyclone, so no forecast change is made. It is a little tempting to raise the intensity by the end, given the recent weaker mid-latitude trough in the models, but there's just too much track uncertainty to mess with the intensity forecast at this time. Key Messages: 1. Although the core of Jerry is expected to move north of the northern Leeward Islands, heavy rainfall and flash floods are possible there today. FORECAST POSITIONS AND MAX WINDS INIT 20/1500Z 18.8N 60.3W 75 KT 85 MPH 12H 21/0000Z 19.6N 62.4W 70 KT 80 MPH 24H 21/1200Z 20.9N 64.7W 65 KT 75 MPH 36H 22/0000Z 22.3N 66.6W 60 KT 70 MPH 48H 22/1200Z 23.6N 68.0W 60 KT 70 MPH 72H 23/1200Z 26.5N 69.0W 65 KT 75 MPH 96H 24/1200Z 29.0N 67.5W 65 KT 75 MPH 120H 25/1200Z 33.0N 64.0W 65 KT 75 MPH $$ Forecaster Blake
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