081
WTNT45 KNHC 120233
TCDAT5
TROPICAL STORM ERIN DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052025
1100 PM AST MON AUG 11 2025
AFTER STRUGGLING EARLIER DURING THE DIURNAL CONVECTIVE MINIMUM, A
LARGE CONVECTIVE BURST HAS FORMED AND PERSISTED OVER THE CENTER OF
ERIN FOR THE PAST SEVERAL HOURS, AND A RECENT GPM MICROWAVE PASS
FROM 11/2237 UTC CONFIRMED THAT THE LOW-LEVEL CENTER IS UNDERNEATH
THIS BURST. THE LATEST SUBJECTIVE INTENSITY ESTIMATES RANGE FROM
35-45 KT, AND THE OBJECTIVE INTENSITY ESTIMATES FROM UW-CIMSS HAVE
CREPT UP SLIGHTLY TO THE 40-45 KT RANGE. THE INITIAL INTENSITY IS
HELD AT 40 KT, WHICH MIGHT BE A TAD CONSERVATIVE.
ERIN CONTINUES MOVING QUICKLY WESTWARD, WITH THE LATEST MOTION
ESTIMATED AT 275/18 KT. THIS GENERAL MOTION WITH A GRADUAL DECREASE
IN FORWARD SPEED IS EXPECTED OVER THE NEXT 2 TO 3 DAYS AS THE
TROPICAL STORM IS STEERED BY A MID-LEVEL SUBTROPICAL RIDGE TO ITS
NORTH. TOWARDS THE END OF THE FORECAST PERIOD, THE RIDGE SHOULD
ERODE SOME, WHICH WOULD ALLOW ERIN TO TURN TOWARD THE WEST-NORTHWEST
AND GAIN SOME LATITUDE. HOWEVER, THERE ARE SOME DIFFERENCES IN THE
GLOBAL MODELS AS TO HOW SIGNIFICANT THE WEAKNESS IN THE RIDGE WILL
BE, AND THIS WILL AFFECT HOW FAR NORTH THE CYCLONE GETS BY DAY 5.
SOME OF THE RECENT MODEL SOLUTIONS ARE A BIT FARTHER TO THE LEFT (OR
SOUTHWEST) AT THE END OF THE FORECAST PERIOD. THE NHC FORECAST IS
NUDGED ONLY VERY SLIGHTLY TO THE LEFT AT DAYS 4-5, AND NOW LIES
SLIGHTLY TO THE NORTH OF THE LATEST CONSENSUS AIDS. BASED ON THE
MODEL SPREAD, THE CONFIDENCE IN THE TRACK FORECAST APPEARS TO BE
ABOUT AVERAGE.
ERIN IS EXPECTED TO REMAIN IN LOW VERTICAL WIND SHEAR CONDITIONS FOR
THE NEXT 3-4 DAYS. THE THERMODYNAMIC ENVIRONMENT IS LESS FAVORABLE
IN THE SHORT-TERM, WITH SEA-SURFACE TEMPERATURES (SSTS) AROUND
26-27C, AND STABLE STRATOCUMULUS CLOUDS NOTED JUST TO THE WEST AND
NORTHWEST OF ERIN. ONLY SLOW STRENGTHENING IS FORECAST DURING THE
NEXT 1 TO 2 DAYS UNTIL ERIN REACHES WARMER WATER. A FASTER RATE OF
INTENSIFICATION IS ANTICIPATED AFTER THAT TIME. THE LATEST NHC
FORECAST IS VERY SIMILAR TO THE PREVIOUS ONE, AND LIES SLIGHTLY
BELOW THE INTENSITY CONSENSUS FOR THE FIRST 36 H. THEREAFTER, THE
NHC INTENSITY FORECAST IS NEAR THE MIDDLE OF THE INTENSITY GUIDANCE
ENVELOPE. IT IS POSSIBLE THAT VERTICAL WIND SHEAR COULD INCREASE IN
4 TO 5 DAYS, BUT THAT WILL DEPEND ON WHERE THE UPPER-LEVEL RIDGE IS
SITUATED IN RELATION TO ERIN, WHICH IS UNCERTAIN AT THIS TIME.
KEY MESSAGES:
1. IT IS STILL TOO EARLY TO DETERMINE WHAT IMPACTS, IF ANY, ERIN MAY
BRING TO THE NORTHERN LEEWARD ISLANDS, BERMUDA, OR THE EAST COAST OF
THE UNITED STATES. AS WE APPROACH THE CLIMATOLOGICAL PEAK OF THE
HURRICANE SEASON, IT IS AN OPPORTUNE TIME TO ENSURE YOUR
PREPAREDNESS PLANS ARE IN PLACE.
FORECAST POSITIONS AND MAX WINDS
INIT 12/0300Z 17.6N 32.3W 40 KT 45 MPH
12H 12/1200Z 17.4N 35.2W 45 KT 50 MPH
24H 13/0000Z 17.2N 38.8W 50 KT 60 MPH
36H 13/1200Z 17.1N 42.2W 55 KT 65 MPH
48H 14/0000Z 17.4N 45.4W 65 KT 75 MPH
60H 14/1200Z 18.0N 48.4W 75 KT 85 MPH
72H 15/0000Z 18.7N 51.3W 85 KT 100 MPH
96H 16/0000Z 20.3N 56.8W 95 KT 110 MPH
120H 17/0000Z 21.9N 61.5W 100 KT 115 MPH
FORECASTER HAGEN
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