Tropical Storm Beryl Discussion Number 3
Wiki-Hurricanes Forecast Center
5:00 PM AST Thu Jul 5 2018
Beryl is creating headaches this afternoon. The eye evident on visible imagery has maintained itself for the past few hours, and this feature has been making intermittent appearances on infrared channels. A satellite estimate of T3.0/45kt from SAB was used to upgrade the storm in a special discussion at 17:45Z, and that is the intensity maintained for this advisory. However, in the absence of reconnaissance aircraft or ASCAT, this estimate is of very low confidence.
Beryl has been moving generally west over the past few hours. A turn toward the west-northwest is expected by tomorrow, and that trajectory should continue for the remainder of the period as the storm is steered by expansive mid-level ridging to its north. Such a track should take Beryl toward the Leeward Islands by late Sunday into Monday.
As noted this morning, small storms have a tendency to rapidly intensify and rapidly dissipate. Beryl is a small but well organized storm in an environment with conflicting signals with regard to its favorability, making this one of the hardest intensity forecasts a meteorologist has to contend with. Wind shear is light, the byproduct of vast anticyclonic flow aloft, and it is expected to remain light for the next 36 hours. With aid from the monsoon trough and a healthy moisture bubble, relative humidity values are currently in the ballmark of 60 percent, where they should remain for the next 24 hours. Ocean temperatures, however, are below 26°C, and are expected to remain marginal for the next few days. Such cool waters would typically negate intensification; however, because of the moist atmospheric column, even shallow convection allows intensification processes to continue, as we have seen during the past 12 hours. The most recent infrared frames show some semblance of dry air wrapping around Beryl, but for now, this is located outside the central dense overcast. Both the SHIPS and LGEM now make Beryl a hurricane around 36 hours from now, a massive disagreement from the global models which barely register the system—this isn't necessarily surprising given how tiny it is. The updated intensity forecast is vastly different from the previous one and now shows Beryl becoming a strong tropical storm tomorrow. Increasing wind shear after 36 hours should cause the storm to degenerate to a strong tropical wave by day 4 despite increasingly warm waters. However, it is still likely to be accompanied by strong winds and precipitation as it moves through the northeastern Leeward Islands, and residents there should be vigilant for changes in the future.
FORECAST POSITIONS AND MAX WINDS
INIT 05/2100Z 45 KT 50 MPH
12H 06/0600Z 50 KT 60 MPH
24H 06/1800Z 55 KT 65 MPH
36H 07/0600Z 55 KT 65 MPH
48H 07/1800Z 50 KT 60 MPH
72H 08/1800Z 40 KT 45 MPH