ZCZC HFOTCDCP4 ALL TTAA00 PHFO DDHHMM Hurricane Norman Discussion Number 36 NWS Central Pacific Hurricane Center Honolulu HI EP162018 500 PM HST Wed Sep 05 2018 It appears the 15 to 20 kt of southwesterly shear is beginning to impact the core of Hurricane Norman. Microwave overpasses at 2259 and 0036 UTC appear to show the eyewall starting to break down. The eye has becoming indistinct, and surrounding convection has taken on a ragged appearance in recent infrared satellite imagery as well. Current intensity numbers from PHFO, JTWC, and SAB were all 5.5, which agree nicely with CIMSS ADT and SATCON. Thus, a current intensity estimate of 105 kt was used for this advisory. It should be noted that this is not meant to reflect intensification from the previous advisory, which appears to have been a bit too conservative. Norman looks as though it has started the anticipated west-northwest motion. When attempting to account for trochoidal wobbles, this new vector appears to be about 290/8. The forecast track philosophy has not changed, with a digging trough in the middle and upper levels north of the main Hawaiian Islands imparting a more northwestward motion with time. The guidance spread increases beyond 24 hours, with some of the reliable global models on the west side of the guidance envelope. However, the consensus tracks through 120 hours, including HCCA and TVCN, continue to agree well with our official track, so few changes were made. It should be noted that none of the reliable guidance suggests direct impacts from Norman on the main Hawaiian Islands. However, as the tropical cyclone will be in our general vicinity for the next couple of days, people should continue to monitor the progress of this system. In addition to increasing southwesterly shear, the tropical cyclone is also over marginal sea surface temperatures of 26.5 to 27C. After 48 hours, sub-26C water lies along the forecast track and even stronger shear is anticipated. Our forecast reflects a slow weakening but remains near the high end of the guidance for the first 24 to 36 hours, then weakens Norman at a rate near the middle of the guidance spread afterwards, but not quite as fast as the GFS- or ECMWF-based SHIPS indicates. Norman is forecast to become a post-tropical remnant low in about 5 days. FORECAST POSITIONS AND MAX WINDS INIT 06/0300Z 20.0N 149.2W 105 KT 120 MPH 12H 06/1200Z 20.5N 150.3W 100 KT 115 MPH 24H 07/0000Z 21.4N 151.4W 90 KT 105 MPH 36H 07/1200Z 22.5N 152.4W 80 KT 90 MPH 48H 08/0000Z 23.6N 153.4W 65 KT 75 MPH 72H 09/0000Z 25.9N 155.4W 40 KT 45 MPH 96H 10/0000Z 27.8N 157.4W 30 KT 35 MPH 120H 11/0000Z 29.8N 159.6W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster R Ballard NNNN
Alternate Formats
About Alternates -
E-Mail Advisories -
RSS Feeds
Cyclone Forecasts
Latest Advisory -
Past Advisories -
About Advisories
Marine Forecasts
Latest Products -
About Marine Products
Tools & Data
Satellite Imagery -
US Weather Radar -
Aircraft Recon -
Local Data Archive -
Forecast Verification -
Deadliest/Costliest/Most Intense
Learn About Hurricanes
Storm Names
Wind Scale -
Prepare -
Climatology -
NHC Glossary -
NHC Acronyms -
Frequently Asked Questions -
AOML Hurricane-Research Division
About Us
About NHC -
Mission/Vision -
Other NCEP Centers -
NHC Staff -
Visitor Information -
NHC Library
NOAA/
National Weather Service
National Centers for Environmental Prediction
National Hurricane Center
11691 SW 17th Street
Miami, Florida, 33165-2149 USA
nhcwebmaster@noaa.gov
Disclaimer
Privacy Policy
Credits
About Us
Glossary
Career Opportunities
Page last modified: Thursday, 08-Aug-2019 14:27:42 UTC