291
WTPZ41 KNHC 081442
TCDEP1
POTENTIAL TROPICAL CYCLONE SIXTEEN-E DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL EP162023
1000 AM CDT SUN OCT 08 2023
THE SYSTEM APPEARS TO BE GETTING SLOWLY BETTER ORGANIZED THIS
MORNING, THOUGH IT REMAINS UNCLEAR IF A WELL-DEFINED CENTER HAS
FORMED. AN SSMIS PASS AT 1110 UTC REVEALED A DECENT CURVED
CONVECTIVE BAND TO THE NORTHWEST OF THE BEST LOW-LEVEL TURNING, BUT
THERE IS A LACK OF CLEAR EVIDENCE OF A TIGHTER LOW-LEVEL CIRCULATION
ON THE LOW-LEVEL 37 GHZ CHANNEL. FIRST-LIGHT VISIBLE IMAGES ON THE
1-MINUTE GOES-18 MESO-SECTOR ALSO REMAIN UNCLEAR ON THE CIRCULATION
DEFINITION. THUS, THE SYSTEM REMAINS A POTENTIAL TROPICAL CYCLONE,
BUT GIVEN THE IMPROVEMENT IN BANDING THE INITIAL INTENSITY WAS
RAISED TO 30 KT, A BIT HIGHER THAN THE TAFB AND SAB DVORAK
ESTIMATES.
FIRST-LIGHT VISIBLE IMAGERY SUGGESTS THE BEST POSITION OF THE SYSTEM
RIGHT NOW IS JUST A LITTLE NORTH AND WEST OF OVERNIGHT ESTIMATE,
RESULTING IN A SLOW NORTHWEST MOTION AT 320/4 KT. THE OVERALL TRACK
REASONING REMAINS UNCHANGED, AS THE SYSTEM IS EXPECTED TO MOVE
NORTH-NORTHWESTWARD OR NORTHWARD OVER THE NEXT 24-36 H, IN BETWEEN A
MID-LEVEL RIDGE CENTERED TO ITS EAST OVER THE NORTHWEST CARIBBEAN,
AND TROPICAL STORM LIDIA LOCATED TO ITS WEST. THIS MOTION SHOULD
BRING THE SYSTEM INLAND OVER MEXICO JUST BEYOND 36 H FROM NOW.
HOWEVER, NOTABLE DIFFERENCES IN THE TIMING OF LANDFALL BETWEEN THE
GUIDANCE REMAIN. THE GFS MODEL, IN ADDITION TO THE
HURRICANE-REGIONAL MODELS BASED ON THE GFS INITIAL CONDITIONS
(HWRF, HMON, HAFS-A/B) CONTINUE TO BE MUCH FASTER THAN OTHER GLOBAL
MODEL GUIDANCE SUCH AS THE ECMWF AND CMC. THIS DISAGREEMENT IS
LIKELY AT LEAST PARTIALLY RELATED TO THE FACT THE DISTURBANCE DOES
NOT YET HAVE A WELL-DEFINED CENTER, AND MAY POTENTIALLY FORM FURTHER
NORTH CLOSER TO LAND. FOR NOW, THE NHC TRACK FORECAST LEANS TOWARDS
THE SLOWER SOLUTIONS, BUT HAS SHIFTED A BIT EAST COMPARED TO THE
PREVIOUS TRACK, AND IS A LITTLE SLOWER THAN THE CONSENSUS AID TVCE.
GIVEN THE GRADUALLY IMPROVING STRUCTURE, THE SYSTEM IS EXPECTED TO
BECOME A TROPICAL CYCLONE SOON, AND MOST OF THE INTENSITY GUIDANCE
SUGGEST CONTINUED INTENSIFICATION UP TILL LANDFALL. THE NHC
INTENSITY FORECAST CONTINUES TO SHOW A PEAK INTENSITY OF 45 KT NEAR
LANDFALL, WHICH IS ON THE HIGH END OF THE INTENSITY GUIDANCE THAT
APPEARS BIASED BY THE GFS AND ITS HURRICANE-REGIONAL MODELS THAT
BRING THE SYSTEM INLAND FASTER THAN SHOWN HERE. IT IS NOTABLE THAT
THE ECMWF AND CMC SHOW A STRONGER TROPICAL CYCLONE THAN THE NHC
FORECAST, MAINLY BECAUSE THEY SPEND A LONGER PERIOD OF TIME
OFFSHORE.
BASED ON THE LATEST FORECAST SHOWING THE SYSTEM NEAR LANDFALL IN
36 H, THE GOVERNMENT OF MEXICO HAS UPGRADED THE AREA PREVIOUSLY
UNDER A TROPICAL STORM WATCH TO A WARNING.
KEY MESSAGES:
1. THE DISTURBANCE IS EXPECTED TO BECOME A TROPICAL STORM BEFORE IT
APPROACHES THE COAST OF SOUTHERN MEXICO ON MONDAY. A TROPICAL STORM
WARNING IS NOW IN EFFECT FOR A PORTION OF THE COAST OF SOUTHERN
MEXICO.
2. HEAVY RAINS FROM THIS SYSTEM WILL LIKELY PRODUCE FLASH AND URBAN
FLOODING, ALONG WITH POSSIBLE MUDSLIDES IN AREAS OF HIGHER TERRAIN
ACROSS THE STATES OF GUERRERO, MICHOACAN AND COASTAL SECTIONS OF
WESTERN OAXACA.
FORECAST POSITIONS AND MAX WINDS
INIT 08/1500Z 15.0N 101.1W 30 KT 35 MPH...POTENTIAL TROP CYCLONE
12H 09/0000Z 15.5N 101.2W 35 KT 40 MPH...TROPICAL CYCLONE
24H 09/1200Z 16.2N 101.3W 40 KT 45 MPH
36H 10/0000Z 17.1N 101.4W 45 KT 50 MPH
48H 10/1200Z 18.0N 101.1W 30 KT 35 MPH...INLAND
60H 11/0000Z...DISSIPATED
FORECASTER PAPIN
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