Issued at 1000 PM CDT Mon Jul 20 2026
161 WTNT42 KNHC 210252 TCDAT2 Tropical Storm Bertha Discussion Number 7 NWS National Hurricane Center Miami FL AL022026 1000 PM CDT Mon Jul 20 2026 The system has become a little better organized with an area of deep convection over the southern semicircle showing slight curvature and limited curved convective bands over the northwestern quadrant. Flight-level winds from both NOAA and Air Force Hurricane Hunter aircraft within the convection to the southwest and southeast of the center indicate that the intensity is near 35 kt, so the system has been upgraded to Tropical Storm Bertha. The aircraft also reported that the central pressure has dropped about 6 mb since this afternoon. The storm has well-defined upper-level outflow to the south and southwest, but outflow is limited over the northern semicircle. There have been several center fixes from the aircraft which indicate very slow, erratic motion. Since the storm has moved very little overall this evening, the best estimate for the initial motion is nearly stationary. Bertha remains sandwiched between two mid-level subtropical high cells, in a region of weak steering currents. The high to the northwest of the storm is forecast to become the dominant steering influence which should induce a west-northwestward or westward motion over the next few days. The official track forecast is similar to the previous NHC prediction, on the southern side of the guidance suite and close to the Google DeepMind ensemble mean. Bertha is being affected by significant north-northeasterly vertical wind shear. Dynamical guidance indicates that this shear will increase during the next couple of days. This should limit intensification of the storm before the center reaches the coast. Simulated satellite imagery from the global models shows the deep convection near or offshore of the coastline, likely due to the shear. Unfavorable atmospheric conditions along with the interaction of land should prevent strengthening late in the forecast period. The official intensity forecast is on the high side of the model guidance. Key Messages: 1. Bertha is expected to bring tropical storm conditions to portions of the Gulf Coast from Alabama westward to southeastern Louisiana Tuesday night and Wednesday, where a Tropical Storm Warning is in effect. Tropical storm conditions are possible for portions of the Florida Panhandle, Metro New Orleans, and the southern Gulf Coast of Louisiana, where a Tropical Storm Watch is in effect. 2. A Storm Surge Watch is in effect for the Alabama, Mississippi, and southeastern Louisiana coasts, where a life-threatening storm surge is possible. 3. Interests elsewhere in Louisiana and Texas should monitor the progress of this system, as additional watches or warnings could be required for portions of that area on Tuesday. 4. Areas of flash flooding will be possible through Thursday along the Gulf Coast and adjacent inland locations from western Florida north of Fort Myers to southern Louisiana with isolated instances of flash flooding possible westward into portions of Texas coast later in the week. FORECAST POSITIONS AND MAX WINDS INIT 21/0300Z 28.2N 85.9W 35 KT 40 MPH 12H 21/1200Z 28.8N 86.6W 40 KT 45 MPH 24H 22/0000Z 29.1N 87.3W 45 KT 50 MPH 36H 22/1200Z 29.3N 88.1W 45 KT 50 MPH 48H 23/0000Z 29.3N 89.4W 40 KT 45 MPH...INLAND 60H 23/1200Z 29.3N 90.7W 35 KT 40 MPH...INLAND 72H 24/0000Z 29.3N 92.1W 30 KT 35 MPH...OVER WATER 96H 25/0000Z 29.3N 94.6W 25 KT 30 MPH...OVER WATER 120H 26/0000Z 29.3N 97.0W 20 KT 25 MPH...POST-TROPICAL $$ Forecaster Pasch
