Issued at 400 AM CDT Wed Jul 22 2026
000 WTNT42 KNHC 220845 TCDAT2 Tropical Storm Bertha Discussion Number 12 NWS National Hurricane Center Miami FL AL022026 400 AM CDT Wed Jul 22 2026 Since the previous advisory, Bertha's appearance has gone downhill, with the deepest convective activity separating further south from the low-level circulation which is now mostly exposed offshore of the coast of Alabama. An Air Force Reserve reconnaissance mission in completing its last pass through Bertha found peak flight level winds of 47 kt, and a minimum central pressure that has risen slightly to 998 mb. While a dropsonde launched in the southeast side of the circulation did find a 500 m layer mean wind of 54 kt, a standard reduction from this layer still yields a slightly reduced intensity of 45 kt for this advisory. Given Bertha's current appearance, this could be generous. A combination of aircraft, radar, and satellite fixes indicate that Bertha is moving due west at 270/4 kt. The primary steering feature resulting in Bertha's short-term motion is a mid-level ridge that has been sliding slowly eastward from the southern Plains to become positioned north of the tropical storm. This evolution should result in Bertha maintaining a westward heading over the next 24-36 h, though continued sheared bursts of deep convection forming south of the center may still act to tug it south of this steering motion. One thing worth keeping an eye on is the possibility a new center may try to reform under these convective bursts in the 24-36 h time-frame like what is depicted in some of the hurricane-regional models, though this is not reflected in the NHC track forecast at this time. The latest track forecast is nearly on top of the previous, but just a little faster, roughly in between the latest Google DeepMind (GDMI) and HFIP Corrected Consensus (HCCA) solutions. Bertha's appearance, the presence of 25-30 kt of northeasterly vertical wind shear, and land interaction are likely to result in slow weakening over the next 24 h or so. After that point, Bertha's future likely depends on if the circulation remains along the Gulf coast, or if it attempts to reform further south under the convective bursts in the northwestern portion of the Gulf. In the former scenario, Bertha's circulation could open up into a trough like in the 00z ECMWF and HWRF solutions. In the latter case, a new center could reform further south and attempt to reorganize like in the HAFS and GFS solutions. For what it's worth, the Google DeepMind ensemble seems to be roughly split between these two possibilities. For now, the NHC intensity forecast does not stray far from the previous one, showing slow weakening before Bertha moves fully inland over Texas in 48 h, becoming post-tropical and dissipating shortly thereafter. This intensity forecast is roughly in the middle of the guidance envelope and closest to the GDMI solution. Key Messages: 1. Tropical storm conditions are expected to continue along portions of the northern Gulf Coast from the western Florida Panhandle to southeastern Louisiana, including the Metro New Orleans area, through tonight. Tropical storm conditions are possible for portions of the southwestern coast of Louisiana tonight into Thursday. 2. A Coastal Flood Warning is in effect for the Mississippi and Louisiana coastlines, where moderate coastal flooding is expected. 3. Interests elsewhere in extreme western Louisiana and along the Upper Texas Coast should monitor the progress of this system, as additional watches or warnings could be required for portions of that area later today. 4. Isolated areas of flash flooding remain possible through early Friday along the central to the western Gulf Coast from western Florida to southern Texas. FORECAST POSITIONS AND MAX WINDS INIT 22/0900Z 29.4N 88.3W 45 KT 50 MPH 12H 22/1800Z 29.4N 89.4W 40 KT 45 MPH...ON THE COAST 24H 23/0600Z 29.3N 91.4W 35 KT 40 MPH...ON THE COAST 36H 23/1800Z 29.3N 93.9W 35 KT 40 MPH...OVER WATER 48H 24/0600Z 29.5N 96.3W 30 KT 35 MPH...POST-TROP/INLAND 60H 24/1800Z...DISSIPATED $$ Forecaster Papin
