je.st
news
Tropical Storm IDA Forecast Discussion Number 6
2015-09-19 22:34:38| National Hurricane Center (Atlantic)
Issued at 500 PM AST SAT SEP 19 2015 000 WTNT45 KNHC 192034 TCDAT5 TROPICAL STORM IDA DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102015 500 PM AST SAT SEP 19 2015 Ida's low-level center has been exposed northwest of the deep convection all day due to about 20 kt of westerly shear, and the initial intensity remains 35 kt based on Dvorak estimates from TAFB and SAB. Vertical shear is expected to be steady or increase slightly during the next 12-24 hours, so little, if any, strengthening is anticipated in the short term. The shear could then decrease between 36-72 hours as Ida moves beneath a narrow upper-level ridge, but there is high uncertainty as to how the upper-level environment will evolve during the next few days. The intensity models continue to disagree on the future intensity. While the GFDL and HWRF bring Ida to hurricane strength in 2 to 3 days, the SHIPS and LGEM models have actually backed off from this morning's runs and show Ida getting no stronger than about 45 kt through day 5. Since the upper-level environment only seems marginally conducive for strengthening, the NHC intensity forecast remains closer to the statistical models and lower than the intensity consensus. Ida has sped up a bit, and the initial motion is 300/12 kt. Low- to mid-level ridging will continue to steer the storm west- northwestward for the next 24 hours. After that time, the ridge is expected to weaken, the steering currents will collapse, and Ida will meander between days 3 through 5. The spread in the track models increases considerably beyond 48 hours, with the ECMWF, GFDL, and HWRF showing a northeastward turn by day 5, while the GFS and UKMET continue to show a westward motion. Given the large spread in the models, very little motion is indicated in the official forecast at the end of the forecast period. This scenario is the same as that shown in previous forecasts. FORECAST POSITIONS AND MAX WINDS INIT 19/2100Z 15.6N 40.8W 35 KT 40 MPH 12H 20/0600Z 16.4N 42.5W 35 KT 40 MPH 24H 20/1800Z 17.6N 44.5W 40 KT 45 MPH 36H 21/0600Z 18.9N 46.1W 45 KT 50 MPH 48H 21/1800Z 19.9N 47.2W 50 KT 60 MPH 72H 22/1800Z 20.5N 48.0W 55 KT 65 MPH 96H 23/1800Z 20.0N 48.0W 55 KT 65 MPH 120H 24/1800Z 20.5N 47.5W 50 KT 60 MPH $$ Forecaster Berg
Tags: number
discussion
storm
tropical
Category:Transportation and Logistics
Latest from this category |
All news |
||||||||||||||||||
|
|||||||||||||||||||