486
WTPZ42 KNHC 282035
TCDEP2
TROPICAL STORM LOWELL DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL EP122026
1100 AM HST FRI AUG 28 2026
LOWELL CONTINUES TO BE AFFECTED BY EASTERLY VERTICAL SHEAR. THE
LOW-LEVEL CENTER IS CURRENTLY EXPOSED TO THE EAST OF THE MAIN
CONVECTIVE MASS, AND SATELLITE IMAGERY IS HINTING THAT THE
MID-LEVEL CENTER IS WEST OR SOUTHWEST OF THE LOW-LEVEL CENTER. A
RECENT ASCAT OVERPASS SHOWED NO TROPICAL-STORM FORCE WINDS IN THE
EASTERN SEMICIRCLE, BUT IT DID NOT SAMPLE THE WINDS UNDER THE
DEEP CONVECTION. SATELLITE INTENSITY ESTIMATES RANGE FROM 30-45
KT, AND THE INITIAL INTENSITY IS HELD AT 40 KT.
LOWELL IS STARTING ITS FORECAST WESTWARD TURN. THE INITIAL MOTION
IS 305/4 KT, AND THE CYCLONE SHOULD START A WESTWARD MOTION WITHIN
THE NEXT 12 H. A GENERAL WESTWARD MOTION SHOULD CONTINUE FOR THE
NEXT 2-3 DAYS AS A LOW- TO MID-LEVEL RIDGE TO THE NORTH OF LOWELL
BECOMES THE PRIMARY STEERING INFLUENCE. THE FORECAST UNCERTAINTY
BECOMES QUITE LARGE BY 120 H DUE TO THE POSSIBLE EFFECT OF THE
LARGER TROPICAL STORM STORM KARINA ON LOWELL'S STEERING CURRENTS.
THE TRACK GUIDANCE HAS A SIGNIFICANT SPREAD IN LOWELL'S FORWARD
SPEED BETWEEN THE FASTER HCCA/UKMET/GOOGLE DEEPMIND ENSEMBLE MEAN
AND THE SLOWER ECMWF/CANADIAN/GFS. THE NEW TRACK FORECAST LEANS
TOWARDS THE FASTER MODELS, AND IT IS A LITTLE SOUTH OF THE PREVIOUS
FORECAST.
THE CURRENT SHEAR IS EXPECTED TO DECREASE IN 18-24 HOURS. AFTER
THAT TIME, CONDITIONS APPEAR GENERALLY FAVORABLE FOR STRENGTHENING,
WITH THE CAVEAT THAT WATER VAPOR IMAGERY SHOWS MID- TO UPPER-LEVEL
DRY AIR NOT FAR NORTH OF THE CYCLONE'S FORECAST TRACK. THE
INTENSITY FORECAST SHOWS ONLY MODEST STRENGTHENING DURING THE NEXT
24 H DUE TO THE SHEAR AND LOWELL'S CURRENT POOR LEVEL OF
ORGANIZATION. AFTER THAT, A FASTER RATE OF DEVELOPMENT IS LIKELY,
PARTICULARLY AFTER 60 H. THE INTENSITY NEAR THE END OF THE FORECAST
PERIOD IS DEPENDENT ON HOW CLOSE LOWELL IS TO KARINA. THE CURRENT
FASTER TRACK FORECAST KEEPS THE CYCLONES FARTHER APART AND THUS
LOWELL IS FORECAST TO CONTINUE STRENGTHENING. HOWEVER, IF THE
SLOWER TRACK GUIDANCE IS CORRECT, LOWELL COULD WIND UP IN STRONGER
SHEAR AND WITH A LOWER INTENSITY DUE TO PROXIMITY TO KARINA.
FORECAST POSITIONS AND MAX WINDS
INIT 28/2100Z 12.5N 133.4W 40 KT 45 MPH
12H 29/0600Z 12.6N 134.0W 40 KT 45 MPH
24H 29/1800Z 12.8N 135.4W 45 KT 50 MPH
36H 30/0600Z 13.0N 136.9W 50 KT 60 MPH
48H 30/1800Z 13.1N 138.6W 55 KT 65 MPH
60H 31/0600Z 13.4N 140.5W 65 KT 75 MPH
72H 31/1800Z 13.6N 142.4W 75 KT 85 MPH
96H 01/1800Z 14.1N 145.6W 90 KT 105 MPH
120H 02/1800Z 14.7N 149.0W 95 KT 110 MPH
FORECASTER BEVEN
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