Issued at 1000 AM CDT Tue Jul 21 2026
000 WTNT42 KNHC 211457 TCDAT2 Tropical Storm Bertha Discussion Number 9 NWS National Hurricane Center Miami FL AL022026 1000 AM CDT Tue Jul 21 2026 Bertha has become slightly better organized this morning. While the low-level center was fully exposed overnight, new deep convection has developed this morning and the center has become at least partially tucked underneath the cold overcast. The Air Force Hurricane Hunters have been investigating the storm, and they reported peak 850-mb flight-level winds of 62 kt within the convection to the southeast of the center, along with layer-averaged dropsonde winds that support raising the initial intensity to 50 kt. The central pressure has fallen slightly to 995 mb. Bertha has deviated north of the forecast track during the past several hours, and the initial motion is north-northwestward (345/3 kt). The near-term track forecast has been adjusted northward to account for this development. While Bertha is currently in fairly weak steering currents, a mid-level ridge centered near the Rockies is expected to move southeastward during the next couple of days. This should cause Bertha to turn more west-northwestward and then westward while it moves near or along the northern Gulf Coast through midweek. While the track models are overall in good agreement on this scenario, there are differences in how much land interaction with southeastern Louisiana will occur, and whether a new center may redevelop off the coast. Little change was made to the NHC track forecast beyond 24 h, and once again this forecast assumes Bertha is able to maintain a cohesive circulation as it passes near or over the northern Gulf Coast. Bertha remains an asymmetric tropical storm, with most of the rainfall and the strongest winds occurring to the south and east of the center. Strong northeasterly vertical wind shear over Bertha is forecast to persist today and tonight, which should make it difficult for Bertha to strengthen much more. Convection is expected to continue pulsing to the south of Bertha's center during this time, and the NHC forecast overall shows gradual weakening over the next few days. The extent of this weakening will depend on how much land interaction occurs during the next couple of days, and it remains possible that Bertha could degenerate into a trough even sooner than forecast due to a disrupted structure within hostile environmental conditions. Some notable watch/warning changes were made with this advisory package. The Tropical Storm Warning was extended eastward across the Florida Panhandle and westward to the Terrebonne/Lafourche Parish Line in Louisiana. In addition, the Storm Surge Watch has been replaced with a Coastal Flood Warning issued by the local forecast office. Minor to moderate coastal flooding is still expected to occur between the Mississippi/Alabama Border and the Mouth of the Mississippi River, with peak values up to 4 ft above ground level. Key Messages: 1. Bertha is expected to bring tropical storm conditions to portions of the Gulf Coast from the Florida Panhandle westward to southeastern Louisiana later today and Wednesday, where a Tropical Storm Warning is in effect. Tropical storm conditions are possible for Metro New Orleans and the southern Gulf Coast of Louisiana, where a Tropical Storm Watch is in effect. 2. A Coastal Flood Warning is in effect for the Mississippi and Louisiana coastlines, where moderate coastal flooding is expected. 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. 4. Isolated areas of flash flooding will be possible through Friday along the Gulf Coast from western Florida into southern Louisiana and the Upper Texas coast. FORECAST POSITIONS AND MAX WINDS INIT 21/1500Z 29.3N 86.3W 50 KT 60 MPH 12H 22/0000Z 29.4N 87.0W 50 KT 60 MPH 24H 22/1200Z 29.5N 88.0W 45 KT 50 MPH 36H 23/0000Z 29.4N 89.5W 40 KT 45 MPH...NEAR THE COAST 48H 23/1200Z 29.3N 91.3W 35 KT 40 MPH...NEAR THE COAST 60H 24/0000Z 29.4N 93.1W 30 KT 35 MPH...OVER WATER 72H 24/1200Z 29.9N 94.9W 25 KT 30 MPH...INLAND 96H 25/1200Z 31.0N 97.5W 20 KT 25 MPH...POST-TROP/INLAND 120H 26/1200Z...DISSIPATED $$ Forecaster Reinhart
