524
WTNT41 KNHC 270840
TCDAT1
TROPICAL STORM FERNAND DISCUSSION NUMBER 15
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062025
500 AM AST WED AUG 27 2025
FERNAND CONTINUES TO SPUTTER ALONG AS A LOPSIDED TROPICAL STORM,
PRODUCING DEEP CONVECTION PRIMARILY ALONG ITS SOUTHERN SEMICIRCLE.
THIS CONVECTIVE ACTIVITY HAS NOT BEEN PARTICULARLY WELL ORGANIZED ON
EITHER GEOSTATIONARY OR MICROWAVE SATELLITE IMAGES. IN FACT,
OVERNIGHT PROXY-VIS SATELLITE IMAGERY SUGGESTS THIS CONVECTIVE
ACTIVITY HAS BEEN STRETCHING THE LOW-LEVEL VORTEX OF THE TROPICAL
CYCLONE, MAKING IT SOMEWHAT ELONGATED. SATELLITE INTENSITY ESTIMATES
THIS MORNING HAVE A WIDE RANGE BETWEEN 30 KT TO 51 KT. OUT OF
DEFERENCE TO THE EARLIER SCATTEROMETER DATA, FERNAND'S INITIAL
INTENSITY REMAINS 40 KT THIS ADVISORY, WHICH IS ALSO ROUGHLY IN THE
MIDDLE OF THE VARIOUS ESTIMATES.
THE ONGOING DEEP CONVECTION APPEARS TO BE IMPACTING FERNAND'S
SHORT-TERM MOTION, WHICH IS EAST OF THE PRIOR FORECAST TRACK, MOVING
AT AN ESTIMATED 080/10 KT. THIS MOTION COULD PERSIST A LITTLE LONGER
GIVEN THE TROPICAL CYCLONE'S ONGOING CONVECTIVE ASYMMETRY. STILL,
FERNAND IS EXPECTED TO RESUME AN ACCELERATING EAST-NORTHEASTWARD
MOTION LATER TODAY, CAUGHT UP IN DEEP-LAYER SOUTHWESTERLY FLOW
DOWNSTREAM OF A LARGE MID-LATITUDE TROUGH OVER EASTERN NORTH
AMERICA. GIVEN THE SHORT-TERM MOTION, THE TRACK GUIDANCE HAS SHIFTED
A LITTLE EAST OF THE PRIOR CYCLE, AND THE LATEST NHC TRACK FORECAST
HAS ELECTED TO GO ALONG THE EASTERN EDGE OF THIS TRACK ENVELOPE,
CLOSE TO THE LATEST HCCA AND EC-AIFS SOLUTIONS. THE ONGOING DEEP
CONVECTION HAS ALSO BOUGHT FERNAND A LITTLE MORE TIME AS A TROPICAL
CYCLONE, THOUGH PROBABLY ONLY ANOTHER 24 HOURS SINCE THE CYCLONE
WILL SOON CROSS A SHARP SEA-SURFACE TEMPERATURE GRADIENT AS IT
PASSES THE NORTH WALL OF THE GULF STREAM. THE NHC INTENSITY FORECAST
SHOWS FERNAND BECOMING POST-TROPICAL IN ABOUT 24 H, AND OPENING UP
INTO A TROUGH AND DISSIPATING IN 60 H.
FORECAST POSITIONS AND MAX WINDS
INIT 27/0900Z 38.3N 50.8W 40 KT 45 MPH
12H 27/1800Z 39.3N 48.2W 40 KT 45 MPH
24H 28/0600Z 41.3N 44.0W 35 KT 40 MPH...POST-TROPICAL
36H 28/1800Z 43.3N 38.3W 35 KT 40 MPH...POST-TROPICAL
48H 29/0600Z 45.2N 30.9W 30 KT 35 MPH...POST-TROP/REMNT LOW
60H 29/1800Z...DISSIPATED
FORECASTER PAPIN
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