Subtropical Storm Alberto Track Chart, Advisory #16
 

Current Location: 21.2N, 85.2W
Geographic Reference: 115 miles ENE of Cozumel, MX
Movement: North at 15 mph
Max Winds: 40 mph gusting to 50 mph
Current Hurricane Severity Index: 2 out of a possible 50 points (1 size, 1 intensity)
Max Predicted Hurricane Severity Index: 5 out of a possible 50 points (2 size, 3 intensity)
Current Radius of Tropical Storm-Force Winds: 90 miles
Max Predicted Radius of Tropical Storm-Force Winds: 115 miles
Organizational Trend: Slowly weakening over the past 6 hours
Forecast Confidence: Average

Key Points

  1. The track has been nudged a little to the west off the southeast Louisiana coast.
  2. We are forecasting Alberto to make landfall on the northern Gulf Coast with 65 mph winds.
  3. There is a 25 percent chance of Alberto becoming a hurricane before landfall.

Our Forecast
Satellite imagery and surface observations indicate that Alberto’s winds are likely well below tropical storm strength this morning. We are waiting for a recon plane to reach the storm to confirm the lower winds. For now, we will keep the winds at 40 mph as we wait for a possible downgrade from the National Hurricane Center.

Regardless of Alberto’s current status, it was never predicted to become better-organized until tonight and Sunday morning, which is indicated in this forecast. The most significant change overnight is that the ensemble models keep Alberto on the northwest track longer before making the sharp right turn toward the Mississippi coast on Sunday evening. This would take the center over eastern Mississippi Canyon and central Viosca knoll on Monday morning before moving into the Mississippi coast on Monday evening. Once inland, Alberto is predicted to accelerate northward along the Mississippi/Alabama border on Tuesday.

As for Alberto’s intensity, we think that the recon plane currently heading for the storm will find that winds are well below the current NHC winds of 40 mph. Whether or not the NHC will downgrade Alberto later this morning is uncertain. Regardless of its classification, Alberto is predicted to become better organized on Sunday as it begins the expected northwest movement. With decreasing wind shear on Sunday and Monday, we are predicting that Alberto’s max winds may reach 65 mph prior to sunrise on Monday. as it passes through northeast Mississippi Canyon. The timing of the northerly turn on Monday is uncertain. It is quite possible that the center could graze southeast Louisiana on Monday and make landfall near the Mississippi/Louisiana border. Our forecast currently takes the center inland between Biloxi and Pascagoula, Mississippi on Monday evening.

Expected Impacts Offshore
Mississippi Canyon/Viosca Knoll/Mobile – With the current slow movement of Alberto, it is possible that squalls which would prevent any helicopter operations may be delayed until noon on Sunday, though that timing is uncertain. Today will likely be the last full day for any helicopter operations there. Squalls with tropical storm conditions and rough seas will arrive on Sunday evening.

Expected Impacts Onshore
Florida Peninsula – Rain bands capable of producing heavy rainfall and gusty winds are expected this afternoon through Monday, resulting in brief street flooding and isolated power outages.

Florida Panhandle through Southern Mississippi and Alabama – Heavy showers and thunderstorms will occur from Sunday through Tuesday or Wednesday, resulting in widespread travel issues. Wind gusts in squalls may produce scattered power outages along the immediate coast of Alabama, Mississippi, and Florida. Widespread power outages are likely near where the center makes landfall.

Our next advisory will be issued by 3PM CDT

Meteorologist: Chris Hebert

Forecast Confidence:   Average Hurricane Severity Index
Fcst Hour Valid Lat. Lon. Max Sustained Winds Max Gusts Category Size Intensity Total
0 9AM CDT Sat May 26 21.20N 85.20W 40 mph 50 mph Subtropical Storm 1 1 2
12 9PM CDT Sat May 26 23.70N 84.70W 35 mph 45 mph Subtropical Storm 0 1 1
24 9AM CDT Sun May 27 26.20N 85.10W 40 mph 50 mph Subtropical Storm 1 1 2
36 9PM CDT Sun May 27 27.60N 86.50W 50 mph 65 mph Tropical Storm 1 2 3
42 3AM CDT Mon May 28 28.20N 87.50W 50 mph 65 mph Tropical Storm 1 2 3
48 9AM CDT Mon May 28 28.70N 88.20W 65 mph 75 mph Tropical Storm 2 3 5
54 3PM CDT Mon May 28 29.50N 88.60W 65 mph 75 mph Tropical Storm 2 3 5
60 9PM CDT Mon May 28 30.30N 88.60W 65 mph 75 mph Tropical Storm 2 3 5
66 3AM CDT Tue May 29 31.30N 88.60W 40 mph 50 mph Tropical Storm 1 1 2
72 9AM CDT Tue May 29 32.20N 88.50W 30 mph 40 mph Tropical Depression 0 0 0
84 9PM CDT Tue May 29 34.40N 88.70W 15 mph 25 mph Remnant Low 0 0 0

The yellow cone represents track error from the previous five hurricane seasons. Over the past five hurricane seasons, the center of the storm tracked within the yellow cone 75% of the time. The cone does not represent the forecast uncertainty in the current advisory for this storm. In addition, hurricane-force winds, very high tides, large waves, and heavy rainfall can often extend well outside the yellow cone.