Continuing to expect the season’s first tropical cyclone.
Fig. 1: The Climate Impact Company 10-day tropical monitor indicates a preliminary forecast track for “Arthur”.
Discussion: The probability of Tropical Disturbance 90L reaching tropical storm strength is 65-70% (80% according NOAA/NHC). Some inhibiting factors is presence of upper shear axis south and north of 90L and while SST is sufficiently warm south and into the southern Bahamas waters to the north cool off rapidly. So…sustaining a tropical storm north of the Bahamas will be difficult. The Climate Impact Company preliminary forecast track is based on a consensus between the ECM and GFS operational models.
Fig. 2: Morning satellite view of the North Atlantic basin.
Fig. 3: The western North Atlantic basin sea surface temperature pattern. SST of 81F is the threshold to sustain a tropical cyclone.