930
WTNT43 KNHC 050852
TCDAT3
TROPICAL DEPRESSION THREE DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL AL032025
500 AM EDT SAT JUL 05 2025
THE DEPRESSION HAS BEEN SHOWING SIGNS OF ORGANIZATION OVERNIGHT,
WITH A SIGNIFICANT BURST OF DEEP CONVECTION CURRENTLY SEEN ON
GOES-19 INFRARED IMAGERY ON THE EASTERN SEMICIRCLE OF THE TROPICAL
CYCLONE. HOWEVER, THE CENTER OF THE TROPICAL DEPRESSION APPEARS TO
STILL BE DISPLACED WESTWARD FROM THIS BURST, ESTIMATED TO BE ON THE
EDGE OF THE LARGER CIRRUS PLUME. AN EARLIER SCATTEROMETER PASS
RECEIVED JUST AFTER THE PRIOR ADVISORY INDICATED THE PEAK WINDS WERE
UP TO 32 KT, SO THE DEPRESSION MAY BE CLOSE TO TROPICAL STORM
STRENGTH. FOR NOW THOUGH, THE INITIAL INTENSITY IS BEING HELD AT 30
KT BLENDING THE LOWER SUBJECTIVE AND HIGHER OBJECTIVE DVORAK
INTENSITY ESTIMATES. AN AIR FORCE RESERVE RECONNAISSANCE MISSION IS
SCHEDULED TO SAMPLE THE SYSTEM LATER THIS MORNING AND SHOULD PROVIDE
MORE IN-SITU INFORMATION ABOUT THE CYCLONE LATER TODAY.
THE DEPRESSION CONTINUES TO MEANDER THIS MORNING, WITH MY BEST GUESS
AT AN ESTIMATED MOTION TO BE AT 030/2-KT. THE TRACK FORECAST IN THE
SHORT-TERM IS SOMEWHAT TRICKY, SINCE THE LOPSIDED NATURE OF THE
CONVECTION WITH THE SYSTEM SUGGESTS THAT THERE COULD BE SOME CENTER
REFORMATIONS/RELOCATIONS TO THE NORTH AND/OR EAST LATER TODAY.
THEREAFTER, THE MAIN STEERING FEATURES ARE A MID-TO-UPPER LEVEL LOW
OVER THE NORTHEASTERN GULF, AND A NARROW MID-LEVEL RIDGE TO THE
NORTHEAST OF THE DEPRESSION. THEIR COMBINED INFLUENCE SHOULD RESULT
IN A GENERAL NORTH-NORTHWESTWARD TRACK OVER THE NEXT 24-36 H. THE
TRACK GUIDANCE THIS CYCLE HAS COME IN FURTHER EAST THIS RUN,
SOMEWHAT IN RESPONSE TO THE ADJUSTED INITIAL POSITION. THE NHC TRACK
FORECAST HAS BEEN SHIFTED EASTWARD IN RESPONSE TO THIS SHIFT IN THE
GUIDANCE, FAVORING THE DETERMINISTIC ECMWF (EMXI) OVER THE GFS
(AVNI), BUT IT IS NOT AS FAR WEST AS SOME OF THE TRACK AIDS,
INCLUDING THE GOOGLE DEEP MIND ENSEMBLE MEAN (GDMI) AND EUROPEAN
DETERMINISTIC AIFS (EAII).
THE VERTICAL WIND SHEAR OVER THE SYSTEM IS PROBABLY THE MOST
UNFAVORABLE IT WILL BE AS THE SYSTEM REMAINS OVER THE WARM GULF
STREAM WATERS. IN FACT, BOTH THE GFS AND ECMWF-BASED SHIPS GUIDANCE
SHOWS THE CURRENT SOUTHWESTERLY SHEAR DECREASING FROM 20 KT
CURRENTLY TO MORE LIKE 10-15 KT OVER THE NEXT 24 H. HOWEVER, THERE
IS SOME DRY MID-LEVEL AIR LURKING TO EAST THAT MIGHT TEMPER MORE
ROBUST INTENSIFICATION. ALL THINGS CONSIDERED, ASSUMING THE
DEPRESSION BECOMES BETTER ALIGNED VERTICALLY, AT LEAST SOME MODEST
INTENSIFICATION SHOULD OCCUR, AND THE LATEST NHC INTENSITY FORECAST
STILL SHOWS A PEAK INTENSITY OF 40 KT BEFORE THE SYSTEM MOVES INLAND
OVER SOUTH CAROLINA ON SUNDAY MORNING. WHILE THIS FORECAST IS ON THE
UPPER END OF THE INTERPOLATED INTENSITY GUIDANCE, THE RAW OUTPUT
FROM BOTH THE 00Z HAFS-A AND HAFS-B HAVE A PEAK INTENSITY A LITTLE
ABOVE THAT VALUE IN 24 H. AFTER LANDFALL, THE CYCLONE SHOULD WEAKEN
AND IS FORECAST TO BECOME POST-TROPICAL IN ABOUT 48 H. IT IS A
LITTLE UNCLEAR IF THE CIRCULATION WILL OPEN UP INTO A TROUGH BY
EARLY NEXT WEEK OR IF SOME REMNANT CIRCULATION WILL MOVE BACK
OFFSHORE BEYOND THAT TIME PERIOD. FOR NOW, THE NHC FORECAST WILL
STICK TO THE FORMER SOLUTION SHOWING DISSIPATION BY 60 H.
GIVEN THE EASTWARD SHIFT IN THE GUIDANCE THIS CYCLE, THE TROPICAL
STORM WATCH HAS BEEN EXTENDED EASTWARD TO CAPE FEAR, NORTH CAROLINA
THIS ADVISORY.
KEY MESSAGES:
1. TROPICAL STORM CONDITIONS ARE POSSIBLE IN THE WATCH AREA
BEGINNING THIS EVENING AND CONTINUING THROUGH SUNDAY MORNING.
2. HEAVY RAINFALL ACROSS THE COASTAL CAROLINAS WILL CAUSE SOME FLASH
FLOODING CONCERNS FROM TROPICAL DEPRESSION THREE FROM TODAY THROUGH
MONDAY. ISOLATED TO SCATTERED FLASH FLOODING COULD OCCUR WITHIN MORE
URBANIZED AREAS ALONG THE COASTAL PLAIN OF THE CAROLINAS.
3. THE SYSTEM IS EXPECTED TO BRING ROUGH SURF AND RIP CURRENTS TO
MUCH OF SOUTHEASTERN UNITED STATES NORTH OF NORTHEASTERN
FLORIDA DURING THE NEXT COUPLE OF DAYS.
FORECAST POSITIONS AND MAX WINDS
INIT 05/0900Z 30.8N 78.6W 30 KT 35 MPH
12H 05/1800Z 31.5N 78.8W 35 KT 40 MPH
24H 06/0600Z 32.6N 79.2W 40 KT 45 MPH
36H 06/1800Z 33.7N 79.4W 35 KT 40 MPH...INLAND
48H 07/0600Z 34.8N 78.8W 30 KT 35 MPH...POST-TROP/INLAND
60H 07/1800Z 36.3N 77.1W 25 KT 30 MPH...POST-TROP/INLAND
72H 08/0600Z...DISSIPATED
FORECASTER PAPIN
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