469
WTNT41 KNHC 172054
TCDAT1
TROPICAL STORM ARTHUR DISCUSSION NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL AL012026
400 PM CDT WED JUN 17 2026
THE CENTER OF ARTHUR APPEARS TO HAVE MOVED INLAND OVER MATAGORDA
COUNTY, TEXAS, EARLY THIS AFTERNOON BASED ON VISIBLE SATELLITE
IMAGES AND SURFACE OBSERVATIONS. HOWEVER, THE CIRCULATION CENTER HAS
BECOME MORE DIFFUSE AND LESS DEFINED OVER THE PAST COUPLE HOURS,
MAKING IT DIFFICULT TO TRACK WITH MUCH CONFIDENCE. A LARGE AREA OF
DEEP CONVECTION PERSISTS OVER THE NORTHWESTERN GULF OF AMERICA, BUT
STRONG WESTERLY SHEAR HAS DISPLACED IT EVEN FARTHER FROM THE CENTER.
MARINE OBSERVATIONS AND DATA FROM THE NOAA HURRICANE HUNTERS SHOW
TROPICAL-STORM-FORCE WINDS ARE STILL ONGOING WITHIN THIS CONVECTION
WELL TO THE EAST AND SOUTHEAST OF THE CENTER. BASED ON A BLEND OF
THE AIRCRAFT DATA AND AVAILABLE SURFACE OBSERVATIONS, THE INITIAL
INTENSITY IS HELD AT 40 KT.
THE LOW-LEVEL MEAN CENTER HAS DEVIATED MORE NORTHWARD THAN EXPECTED
TODAY, AND THE LONG-TERM MOTION ESTIMATE IS NORTH-NORTHEASTWARD AT
ABOUT 6 KT. MOST MODELS SUGGEST THE CIRCULATION CENTER WILL
DISSIPATE WITHIN THE NEXT 6-12 H, BUT A CONTINUED MOTION TOWARD THE
NORTH-NORTHEAST IS FORECAST FOR ARTHUR OR ITS LOW-LEVEL REMNANTS
THROUGH TONIGHT. THIS UPDATED TRACK FORECAST HAS SHIFTED LEFT
(FARTHER INLAND) DUE TO THE CENTER RELOCATION THIS AFTERNOON.
HOWEVER, THIS IS OF LITTLE CONSEQUENCE AS THE GREATEST IMPACTS FROM
ARTHUR ARE STILL BEING FELT WELL TO THE EAST OF ITS CENTER.
NOW THAT THE CENTER OF ARTHUR IS INLAND, WEAKENING IS EXPECTED
WHILE IT CONTENDS WITH STRONG WESTERLY SHEAR AND SOME DRIER
MID-LEVEL AIR INFILTRATING FROM THE WEST. MODEL-SIMULATED SATELLITE
IMAGERY FROM THE GFS AND ECMWF SUGGEST THE ASSOCIATED CONVECTION
SHOULD MOSTLY COLLAPSE TONIGHT. THE 12-H FORECAST POINT SHOWS
REMNANT LOW STATUS, BUT IT COULD JUST AS LIKELY DISSIPATE BEFORE
THAT TIME. THE ECMWF AND CANADIAN MODELS STILL SUGGEST A POTENTIAL
FOR LOW PRESSURE DEVELOPMENT OVER THE WESTERN ATLANTIC LATE THIS
WEEK OR THIS WEEKEND AS REMNANT VORTICITY FROM ARTHUR EMERGES OFF
THE SOUTHEAST U.S. COAST. HOWEVER, IT IS UNCLEAR HOW TROPICAL IN
NATURE THIS SYSTEM WOULD BE IF IT WERE TO DEVELOP, SO WE WILL
CONTINUE TO MONITOR MODEL TRENDS.
HEAVY RAINFALL AND LIFE-THREATENING FLASH FLOODING REMAIN THE
PRIMARY HAZARD, AND IT IS STRESSED THAT THIS THREAT EXTENDS WELL
AWAY FROM THE CENTER AND WILL PERSIST EVEN AFTER ARTHUR DISSIPATES.
THERE IS ALSO AN INCREASED TORNADO THREAT FOR PORTIONS OF THE
SOUTHEASTERN U.S. THROUGH THURSDAY.
KEY MESSAGES:
1. POTENTIALLY LIFE-THREATENING FLASH FLOODING AND URBAN FLOODING
ARE LIKELY THROUGH FRIDAY ACROSS SOUTHERN LOUISIANA, SOUTHERN
MISSISSIPPI, SOUTHERN ALABAMA, SOUTHWESTERN GEORGIA, AND THE FLORIDA
PANHANDLE. SCATTERED MINOR RIVER FLOODING IS EXPECTED, WITH THE
POTENTIAL FOR ISOLATED MODERATE TO MAJOR RIVER FLOODING. ONGOING
HEAVY RAINFALL COULD PROLONG THE FLOOD THREAT THROUGH THE WEEKEND.
2. TROPICAL-STORM-FORCE WINDS, ESPECIALLY IN GUSTS, ARE EXPECTED
ALONG THE UPPER TEXAS AND LOUISIANA COASTS DURING THE NEXT FEW
HOURS WHERE A TROPICAL STORM WARNING IS IN EFFECT.
3. MINOR TO MODERATE COASTAL FLOODING IS EXPECTED ALONG PORTIONS OF
THE UPPER TEXAS AND LOUISIANA COASTLINES TODAY.
FORECAST POSITIONS AND MAX WINDS
INIT 17/2100Z 28.9N 96.1W 40 KT 45 MPH...INLAND
12H 18/0600Z 30.8N 94.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
24H 18/1800Z...DISSIPATED
FORECASTER REINHART
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