486
WTPZ44 KNHC 212036
TCDEP4
TROPICAL STORM NARDA DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL EP142025
300 PM CST SUN SEP 21 2025
SATELLITE IMAGES INDICATE THAT THE LOW PRESSURE AREA A COUPLE OF
HUNDRED MILES SOUTH OF THE SOUTHERN COAST OF MEXICO IS PRODUCING A
LARGE AREA OF DEEP CONVECTION. A RECENT SCATTEROMETER PASS SHOWED
A WELL-DEFINED CIRCULATION, ALBEIT A BIT ELONGATED, ALONG WITH A
LARGE AREA OF 30-35 KT WINDS ON THE NORTHERN SIDE. THUS, A TROPICAL
STORM HAS FORMED, AND NARDA'S INTENSITY IS SET TO 35 KT, CONSISTENT
WITH THE SCATTEROMETER WINDS AND THE 18Z TAFB CLASSIFICATION OF
T2.5.
NARDA APPEARS TO BE MOVING NORTHWESTWARD AT ABOUT 9 KT. THE STORM
SHOULD TURN WEST-NORTHWESTWARD BY TOMORROW AND WESTWARD IN A COUPLE
OF DAYS WITH A GRADUAL INCREASE IN FORWARD SPEED DUE TO A LARGE
RIDGE OVER NORTHWESTERN MEXICO. THE BIGGEST DIFFERENCE IN THE
TRACK GUIDANCE IS RELATED TO HOW FAST NARDA MOVES. THE NHC
FORECAST IS ON THE QUICK SIDE OF THE GUIDANCE, GIVEN THE STRENGTH
OF THE RIDGE AND FOLLOWING THE LEAD OF THE CORRECTED-CONSENSUS
GUIDANCE. NONE OF THE MODELS BRING TROPICAL-STORM-FORCE WINDS NEAR
MEXICO AT THIS TIME, SO NO WATCHES SEEM TO BE NEEDED.
THE STORM SHOULD BE OVER WARM WATERS WITH MODERATE NORTHEASTERLY
SHEAR FOR THE NEXT SEVERAL DAYS. THE MODEL GUIDANCE RESPOND TO
THIS ENVIRONMENT BY GENERALLY SHOWING GRADUAL INTENSIFICATION FOR
THE NEXT FEW DAYS, FOLLOWED BY A LEVELING OFF AS THE STORM PASSES
OVER MARGINALLY WARM WATERS. WHILE THE MODELS ARE IN FAIRLY GOOD
AGREEMENT FOR AN INITIAL FORECAST, THIS SHOULDN'T BE CONSIDERED TOO
CONFIDENT BECAUSE OF THE WELL-KNOWN PREDICTABILITY CHALLENGES OF A
MODERATE-SHEAR ENVIRONMENT. THE NHC FORECAST LIES BETWEEN THE
MODEL CONSENSUS AND THE NOAA CORRECTED-CONSENSUS HCCA.
FORECAST POSITIONS AND MAX WINDS
INIT 21/2100Z 14.7N 99.7W 35 KT 40 MPH
12H 22/0600Z 15.5N 100.8W 40 KT 45 MPH
24H 22/1800Z 16.1N 102.6W 45 KT 50 MPH
36H 23/0600Z 16.3N 104.6W 55 KT 65 MPH
48H 23/1800Z 16.4N 106.8W 65 KT 75 MPH
60H 24/0600Z 16.5N 109.0W 75 KT 85 MPH
72H 24/1800Z 16.5N 111.5W 80 KT 90 MPH
96H 25/1800Z 16.7N 116.7W 85 KT 100 MPH
120H 26/1800Z 17.4N 121.7W 85 KT 100 MPH
FORECASTER BLAKE
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