121
WTPZ41 KNHC 300837
TCDEP1
TROPICAL STORM FLOSSIE DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL EP062025
300 AM CST MON JUN 30 2025
A 30/0357 UTC ASCAT-B PASS OVER FLOSSIE SHOWED A SIZABLE AREA OF
30-35 KT WINDS IN THE NE QUADRANT, WITH 25-30 KT WINDS WRAPPING INTO
PORTIONS OF THE SE AND NW QUADRANTS. THE ASCAT DATA ALSO INDICATES
THAT THE RMW HAS CONTRACTED TO ABOUT 40 N MI. SSMIS AND GMI
MICROWAVE PASSES BETWEEN 00-03Z WERE ALSO HELPFUL IN DIAGNOSING THE
POSITION AND STRUCTURE OF FLOSSIE. SINCE THE TIME OF THE
ABOVE-MENTIONED MICROWAVE IMAGES, GOES SATELLITE IMAGERY INDICATES
THAT FLOSSIE HAS STARTED TO BECOME BETTER ORGANIZED, AND IT APPEARS
THAT THE LOW-LEVEL CENTER IS LIKELY UNDERNEATH THE NORTHERN PORTION
OF THE CENTRAL CONVECTIVE AREA, WHICH HAS INCREASED IN SIZE AND
CONTAINS A LARGE AREA OF CLOUD TOPS COLDER THAN -80 DEGREES C. THE
INITIAL INTENSITY IS SET TO 40 KT DUE TO THE IMPROVED ORGANIZATION
SINCE THE TIME OF THE ASCAT PASS. THIS ESTIMATE IS ALSO IN LINE
WITH THE LATEST OBJECTIVE INTENSITY ESTIMATES FROM THE UW-CIMSS ADT,
AIDT AND DPRINT, WHICH ARE RUNNING IN THE 40-45 KT RANGE.
ATMOSPHERIC AND OCEANIC CONDITIONS ARE EXPECTED TO REMAIN FAVORABLE
FOR INTENSIFICATION FOR AT LEAST ANOTHER 48 H AS FLOSSIE MOVES
THROUGH AN ENVIRONMENT OF WARM WATER, WEAK VERTICAL WIND SHEAR, AND
A MOIST MID-LEVEL TROPOSPHERE. RAPID INTENSIFICATION REMAINS A
DISTINCT POSSIBILITY OVER THE NEXT DAY OR TWO. THE NHC FORECAST
CONTINUES TO SHOW STEADY TO RAPID INTENSIFICATION. THE OFFICIAL
FORECAST IS NEAR THE HIGHER END OF THE INTENSITY GUIDANCE ENVELOPE.
BEYOND 48 H, FLOSSIE SHOULD GRADUALLY ENCOUNTER A DRY AND STABLE
AIRMASS AND CROSS OVER COOLING WATERS WHICH WILL LEAD TO STEADY
WEAKENING.
THE INITIAL MOTION ESTIMATE IS TOWARD THE NORTHWEST, OR 315/9 KT. A
MOTION BETWEEN WEST-NORTHWEST AND NORTHWEST SHOULD CONTINUE FOR THE
NEXT FEW DAYS AS FLOSSIE MOVES THROUGH A BREAK IN THE SUBTROPICAL
RIDGE. THE NHC TRACK FORECAST IS MOSTLY UNCHANGED FROM THE PREVIOUS
OFFICIAL FORECAST, AND LIES IN BETWEEN THE SIMPLE AND CORRECTED
CONSENSUS AIDS.
THE LATEST NHC FORECAST HAS NECESSITATED THE ISSUANCE OF A TROPICAL
STORM WARNING FOR PORTIONS OF THE COAST OF MEXICO, AS
TROPICAL-STORM-FORCE WIND SPEED PROBABILITIES ARE IN THE 40 TO 50
PERCENT RANGE FOR PORTIONS OF THE AREA. RESIDENTS OF MEXICO SHOULD
STAY UPDATED ON THE LATEST FORECAST. A SHIFT IN TRACK TO THE RIGHT
OF THE OFFICIAL FORECAST COULD BRING MORE SIGNIFICANT IMPACTS TO THE
COAST OF SOUTHWESTERN MEXICO.
KEY MESSAGES:
1. THE OUTER BANDS OF TROPICAL STORM FLOSSIE MAY BRING LOCALLY HEAVY
RAINFALL TO THE MEXICAN STATES OF OAXACA, GUERRERO, MICHOACáN,
COLIMA, AND JALISCO THROUGH MID-WEEK. LIFE-THREATENING FLOODING AND
MUDSLIDES ARE POSSIBLE, PARTICULARLY IN AREAS OF STEEP TERRAIN.
2. A TROPICAL STORM WARNING HAS BEEN ISSUED FOR A PORTION OF
SOUTHWESTERN MEXICO, WHERE TROPICAL STORM CONDITIONS ARE EXPECTED
LATE TODAY THROUGH TUESDAY.
FORECAST POSITIONS AND MAX WINDS
INIT 30/0900Z 15.0N 101.8W 40 KT 45 MPH
12H 30/1800Z 15.7N 102.9W 50 KT 60 MPH
24H 01/0600Z 16.8N 104.6W 65 KT 75 MPH
36H 01/1800Z 17.7N 106.3W 80 KT 90 MPH
48H 02/0600Z 18.5N 107.7W 85 KT 100 MPH
60H 02/1800Z 19.4N 108.8W 80 KT 90 MPH
72H 03/0600Z 20.4N 109.8W 65 KT 75 MPH
96H 04/0600Z 22.7N 111.9W 45 KT 50 MPH...POST-TROPICAL
120H 05/0600Z 24.9N 114.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
FORECASTER HAGEN
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