Issued at 300 PM CST Sun Sep 21 2025
000 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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