228
WTNT45 KNHC 120845
TCDAT5
TROPICAL STORM ERIN DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052025
500 AM AST TUE AUG 12 2025
THE STORM HAS NOT BECOME SIGNIFICANTLY BETTER ORGANIZED ON
GEOSTATIONARY SATELLITE IMAGERY OVER THE PAST FEW HOURS. DEEP
CONVECTION HAS DIMINISHED IN INTENSITY, AS EVIDENCED BY A WARMING OF
THE CLOUD TOPS. AN AMSR MICROWAVE IMAGE FROM A FEW HOURS AGO SHOWED
A WELL-DEFINED BANDING FEATURE OVER THE SOUTHERN SEMICIRCLE OF THE
SYSTEM. SUBJECTIVE DVORAK INTENSITY ESTIMATES RANGE FROM 35 TO 45
KT AND OBJECTIVE ESTIMATES FROM UW-CIMSS ARE GENERALLY NEAR 40 KT.
THUS THE ADVISORY INTENSITY IS HELD AT 40 KT.
ERIN CONTINUES ITS RAPID WESTWARD MOTION, AT AROUND 265/19 KT.
A STRONG 500 MB RIDGE IS SITUATED TO THE NORTH OF THE CYCLONE,
RESULTING IN A STRONG EASTERLY STEERING CURRENT. THE TROPICAL
CYCLONE SHOULD CONTINUE ON A GENERAL WESTWARD HEADING FOR THE NEXT
FEW DAYS WITH A GRADUAL DECREASE IN FORWARD SPEED AS THE RIDGE
WEAKENS SLIGHTLY. LATER IN THE FORECAST PERIOD, THE RIDGE IS
EXPECTED TO WEAKEN A LITTLE MORE, AND A MORE WEST-NORTHWESTWARD
TRACK IS LIKELY. THE OFFICIAL FORECAST TRACK IS A LITTLE LEFT, OR
SOUTH, OF THE PREVIOUS ONE IN 3-5 DAYS, AND VERY CLOSE TO THE
LATEST DYNAMICAL MODEL CONSENSUS. THIS ALSO VERY SIMILAR TO THE
MEAN OF THE GFS AND ECMWF SOLUTIONS. THE SPREAD OF THE TRACK
MODELS SUGGEST NEAR-AVERAGE CONFIDENCE IN THE NHC FORECAST.
DURING THE FORECAST PERIOD, ERIN WILL BE TRAVERSING WARMER
OCEAN WATERS AND THE SHIPS MODEL DIAGNOSES LOW VERTICAL WIND SHEAR
OVER THE SYSTEM FOR THE NEXT SEVERAL DAYS. HOWEVER, THE MODEL DOES
NOT INDICATE AN INCREASE IN THE ENVIRONMENTAL LOW- TO
MID-TROPOSPHERIC HUMIDITY DURING THE NEXT 72 HOURS OR SO.
NONETHELESS, GIVEN THE LOW SHEAR AND INCREASING SSTS, STRENGTHENING
IS EXPECTED. THE OFFICIAL INTENSITY FORECAST IS AT THE HIGH END OF
THE MODEL GUIDANCE AND SHOWS ERIN BECOMING A MAJOR HURRICANE IN
AROUND 5 DAYS. THERE IS SIGNIFICANT UNCERTAINTY IN INTENSITY
PREDICTIONS AT THIS TIME RANGE.
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, THIS IS AN OPPORTUNE TIME TO ENSURE YOUR
PREPAREDNESS PLANS ARE IN PLACE.
FORECAST POSITIONS AND MAX WINDS
INIT 12/0900Z 17.4N 34.3W 40 KT 45 MPH
12H 12/1800Z 17.2N 37.2W 45 KT 50 MPH
24H 13/0600Z 17.0N 40.5W 50 KT 60 MPH
36H 13/1800Z 17.0N 43.6W 55 KT 65 MPH
48H 14/0600Z 17.4N 46.8W 65 KT 75 MPH
60H 14/1800Z 18.0N 49.9W 75 KT 85 MPH
72H 15/0600Z 18.7N 52.7W 85 KT 100 MPH
96H 16/0600Z 20.0N 58.0W 95 KT 110 MPH
120H 17/0600Z 21.5N 62.5W 100 KT 115 MPH
FORECASTER PASCH
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