Alberto Struggles to Gain Full Tropical Character Due to Gulf Water Temperatures

Ragged Looking Alberto Tries To Gain Tropical Characteristics Sunday
05/26/2018, 7:42 am EDT
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A significant contribution to the inability of Alberto to gain full tropical characteristics was the below threshold sea surface temperatures along Alberto's trek through the eastern Gulf of Mexico. SST of 82F/28C are generally required for a full tropical cyclone and Alberto encountered 80-81F for most of eastern Gulf. Warming of the Gulf surface just prior to landfall later today may allow some strengthening.

Discussion: Subtropical Storm Alberto is located about 110 miles south of the western Florida Peninsula moving northwest at 7 mph with top wind of 65 mph and central pressure 990 MB. Alberto has not been able to fully gain tropical characteristics primarily due to a water surface temperature just beneath the threshold to sustain a full tropical cyclone. The inability to strengthen to a full tilt tropical feature has allowed dry air to entrain into the storm making the convection near the center of Alberto somewhat limited.

Although NOAA/NHC indicates a strong subtropical storm (65 mph wind) Alberto is quite weak with limited direct associated weather and wind. However, indirectly the general environment surrounding Albert will continue to produce a heavy rain risk for Alabama to Georgia and points north as Albert slowly weakens heading toward the Midwest U.S. for midweek.

Alberto crosses warmer water today just prior to striking the western Florida Peninsula late this afternoon. So some strengthening/better organization is still possible. The primary issue today is heavy rain (several in.) across the central and western Florida Panhandle and central/eastern Alabama. Severe thunderstorms are possible from the Florida Panhandle across Georgia. The heavier rain and severe weather threat lifts north to the central/east Tennessee Valley tomorrow.

NOAA/NHC indicates tropical storm force wind is possible from Mobile, AL to Panama City, FL upon landfall of Alberto this afternoon to early evening. This envelope of tropical storm force wind risk is likely too large but tropical storm force wind is likely near and just east of landfall for the western Florida Peninsula coastline.

Storm surge models indicate the largest height in the 3-4 foot range in the northwest Florida coast south and southeast of Tallahassee.

Interaction between the remains of Alberto and a cold front to the north will cause excessive rainfall amounts this week for the Tennessee Valley into Illinois/Indiana and eastward throughout the Mid-Atlantic region.

Fig. 1: NOAA/NHC Subtropical Storm Alberto forecast.

Fig. 2: Satellite view of Subtropical Storm Alberto this morning.

Fig. 3: Sea surface temperature for the Gulf of Mexico.

Fig. 4: Heavy rainfall forecast issued by NOAA/NHC associated with Alberto.

Fig. 5: NOAA/NHC tropical storm force wind risk profile.