Posted on 07/11/2003 5:03:05 AM PDT by john316
Claudette has changed little in strength overnight and the center is now located over the extreme northeastern tip of the Yucatan Peninsula. Latest satellite imagery continues to show a rather ragged looking tropical cyclone with most of the thunderstorms still located north and east of the center. The outflow has improved somewhat to the north and east of the center even though there still appears to be some shear affecting the system from the southwest. Claudette is expected to re-emerge over the southern Gulf later this morning, at which time a slow strengthening trend will begin, especially if the shear diminishes further. There remains a great deal of uncertainty in the overall strength of Claudette prior to making landfall over south Texas as conditions are expected to become increasingly favorable for strengthening with time. We are still forecasting Claudette to become a Category One hurricane prior to making landfall, however, if the shear diminishes completely, then additional strengthening will be possible.
Claudette continues to move towards the northwest in response to a weakening ridge of high pressure located north of the storm. We expect this general motion to continue with a gradual decrease in forward speed over the next 24 hours as steering currents continue to weaken . Beyond 24 hours, we expect Claudette to make a gradual turn towards the west as high pressure re-builds across the northern Gulf. Just how soon Claudette makes this westward turn will ultimately determine how far north landfall occurs. A later turn would result in landfall farther north, perhaps along the upper Texas coast or even southwestern Louisiana. If Claudette turns westward sooner, landfall would occur farther south, over northern Mexico.
The next forecast track will be issued near 10:30am CDT this morning
morning satellite imagery indicates the center of Claudette is over the northeastern Yucatan Peninsula to the southwest of broadly curved deep convection. An Air Force reserve hurricane hunter aircraft reports flight-level winds of 55 kt northeast of the center and suggests the central pressure remains near 1008 mb. Based on this and persistence from the previous advisory...the maximum winds remain 50 kt.
The initial motion is 315/12...although visible imagery suggests it might be a little slower. Water vapor imagery shows a weakening upper-level low west of Claudette...with broad troughing over the eastern United States between large anticyclones over the southwestern U.S. And the western Atlantic. Enough ridging remains east and northeast of Claudette to keep the storm moving northwestward in the short term...with gradual deceleration as the cyclone approaches the weakness created by the trough. After 36 hr...large-scale models suggests the trough should slowly weaken and move eastward...which would allow ridging to build and steer Claudette more westward. Most NHC track guidance agrees with this scenario...although BAMD...nhc98...and LBAR move the cyclone northward to the northern Gulf Coast. The official forecast will go with the westward turn...calling for a landfall near the mouth of the Rio Grande in about 96 hr.
Claudette remains disorganized and in significant southerly shear. This and land interaction will likely prevent strengthening for 12-24 hours. After that...the intensity depends on how a large upper-level anticyclone forecast by the dynamical models actually develops. The UKMET and NOGAPS develop the anticyclone over Claudette. On the other hand...the GFS and Canadian develop the anticyclone south of the forecast track... which would expose the storm to 15-30 kt of westerly shear. The models have been too aggressive in developing this feature to put full Faith in the UKMET and NOGAPS...so the intensity forecast will call for only gradual strengthening. However...if the GFS and Canadian verify... strengthening could be even slower than currently forecast.
Claudette is quite disorganized this afternoon. The low-level center has become elongated east-northeast to west-southwest...and there are 3 or 4 cloud swirls/vorticity centers rotating around the mean center. The strongest remaining convection is well east of the center. Based on the 50-55 kt flight level winds reported earlier by the reconnaissance aircraft and the degraded satellite appearence...the initial intensity is reduced to 45 kt.
The initial motion is an uncertain 310/12. Water vapor imagery shows an upper-level cyclonic shear axis west of Claudette...with a mid/upper-level trough over the central and eastern United States extending southwestward to near 32n92w. A large upper-level anticyclone is centered near Grand Cayman island. Surface and rawinsonde data indicates low-level ridging over the northern Gulf of Mexico. Present indications are the trough will reach its maximum southern extent near 85w or east of the longitude of Claudette...and that the trough is unlikely to recurve the cyclone. Most dynamic guidance responds to this pattern by moving Claudette northwest for 24-48 hours...followed by a gradual westward turn. The LBAR and the mm5 take the storm toward Louisiana...which looks strange in light of the northerly 500 mb flow that all models forecast in that area. The UKMET has also jumped further north... but is inconsistent with its previous runs and is thus discounted for the moment. The track forecast will be an update of the previous package and down the middle of the westward model suite.
Claudette remains in significant southerly shear. This and the current disorganization will likely prevent strengthening for 12-24 hours. After that...the intensity depends on how a large upper-level anticyclone forecast by the dynamical models actually develops. The NOGAPS is now the only model to develop the anticyclone over Claudette. The UKMET...GFS...and Canadian develop the anticyclone south of the forecast track... which would expose the cyclone to some westerly shear. This looks like the most likely scenario...and the intensity forecast calls for only slow development in response. It should be noted that if Claudette strengthens significantly during the first 24 hr...the storm could move more toward the north due to the southerly upper-level flow. The chances of this appear low at this time.
The NOAA Gulfstream IV jet is currently conducting a synoptic surveillance mission...with the data to be used in the 00z models.
This morning, most of the models show the storm headed towards Brownsville, and none show Corpus Christi in the path. One model, though, projects the storm to hit Houston. The NHC will undoubtedly ignore that particular model out in its next update.
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