000 WTNT44 KNHC 121454 TCDAT4 Tropical Storm Karl Discussion Number 4 NWS National Hurricane Center Miami FL AL142022 1000 AM CDT Wed Oct 12 2022 Despite the ragged satellite presentation, Karl has slightly strengthened this morning. An Air Force Reserve Hurricane Hunter aircraft investigating the storm found SFMR wind speeds of 37 kt and a decreased extrapolated minimum central pressure. Given these data, the initial intensity was raised to 40 kt on the earlier intermediate advisory, and it remains at that value for now. Karl is slowly moving northward at about 3 kt. A general northward motion is forecast for the next 12 hours. Thereafter, a building ridge over northern Mexico is expected to steer Karl generally southward until it makes landfall between 60-72 h. The model guidance has continued to shift eastward and shows Karl making the hairpin turn to the right, instead of left as shown in earlier cycles. The official track forecast has been shifted rather significantly to the east in order to remain within the model guidance envelope. The NHC track, however, is on the westernmost edge of the envelope, and should the guidance continue to shift eastward, further adjustments may be needed in future advisories. The Tropical Storm Watch has been extended eastward to Frontera, Mexico to account for the shift in the track forecast. Based on the satellite appearance, the deep-layer vertical wind shear over Karl seems to be increasing. Global model guidance suggests the shear will continue to increase and possible force dry mid-level humidities located upshear into the circulation. Therefore, the official intensity forecast no longer shows additional strengthening and instead holds Karl at 40 kt for the next day or so followed by slight weakening before landfall. The cyclone is expected to rapidly decay and dissipate once it moves inland. Key Messages: 1. Heavy rainfall could produce instances of flash flooding, with mudslides in areas of higher terrain, across portions of Veracruz and Tabasco states in Mexico. 2. Tropical storm conditions are possible in the watch area in Mexico starting on Thursday night or Friday. FORECAST POSITIONS AND MAX WINDS INIT 12/1500Z 21.7N 94.7W 40 KT 45 MPH 12H 13/0000Z 22.0N 94.8W 40 KT 45 MPH 24H 13/1200Z 21.6N 94.8W 40 KT 45 MPH 36H 14/0000Z 20.9N 94.6W 40 KT 45 MPH 48H 14/1200Z 20.0N 94.5W 35 KT 40 MPH 60H 15/0000Z 19.1N 94.8W 35 KT 40 MPH 72H 15/1200Z 18.1N 95.4W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 16/1200Z...DISSIPATED $$ Forecaster Bucci/Brown