WTNT44 KNHC 020843 RRA

TCDAT4



TROPICAL STORM HERMINE DISCUSSION NUMBER  20

NWS NATIONAL HURRICANE CENTER MIAMI FL       AL092016

500 AM EDT FRI SEP 02 2016



HERMINE MADE LANDFALL NEAR ST. MARKS, FLORIDA, AROUND 0530 UTC WITH

70-KT WINDS. SINCE THAT TIME RADAR DATA AND SURFACE OBSERVATIONS

INDICATE THAT THE CENTER HAS CONTINUED TO MOVE INLAND. THE RADAR

PRESENTATION HAS DETERIORATED, AND IT IS ESTIMATED THAT HERMINE

HAS WEAKENED TO TROPICAL STORM STATUS WITH 60-KT WINDS. ADDITIONAL

WEAKENING IS ANTICIPATED WHILE THE CYCLONE MOVES FARTHER INLAND, BUT

IT COULD REINVIGORATE AS AN EXTRATROPICAL CYCLONE WHEN IT MOVES

OVER WATER AND INTERACTS WITH A BAROCLINIC TROUGH IN ABOUT 48 HOURS.



THE BEST ESTIMATE OF THE INITIAL MOTION 025/12 KT. HERMINE IS

EMBEDDED WITHIN THE SOUTHWESTERLY FLOW AHEAD OF A MID-LATITUDE

TROUGH, AND THIS FLOW PATTERN SHOULD STEER THE CYCLONE TOWARD THE

NORTHEAST WITH AN INCREASE IN FORWARD SPEED DURING THE NEXT DAY

OR TWO. TRACK MODELS ARE IN VERY GOOD AGREEMENT DURING THIS

PERIOD. AFTER THAT TIME, WHEN HERMINE BEGINS TO INTERACT WITH

A BAROCLINIC TROUGH, THE CYCLONE SHOULD SLOW DOWN SIGNIFICANTLY

AND BEGIN TO MEANDER. ON DAYS 3-5, THE TRACK GUIDANCE BECOMES RATHER

DIVERGENT, DECREASING CONFIDENCE IN THE FORECAST.  THE NHC

PREDICTION KEEPS AN EXTRATROPICAL CYCLONE MOVING LITTLE OR DRIFTING

NORTHWARD A FEW HUNDRED MILES OFF THE NORTHEASTERN U.S COAST DURING

THAT TIME. THERE IS A POSSIBILITY THAT THE SYSTEM COULD REGAIN SOME

TROPICAL CHARACTERISTICS IN 4-5 DAYS, BUT THIS REMAINS UNCERTAIN AS

INDICATED IN THE PREVIOUS NHC FORECAST.



KEY MESSAGE:



1. HERMINE IS EXPECTED TO BECOME A POST-TROPICAL CYCLONE WHILE=