The Christophe Clement-trained Cariba will try to win for the first time in 14 months when she takes on an optional-claiming field on Sunday at Gulfstream Park in Hallandale Beach, Fla. This 4-year-old daughter of Cairo Prince has one win and two seconds in five career starts. Her last win came three starts ago, in February 2019. Cariba has been installed as the 7-2 morning-line favorite in Race 10, an optional $25,000 claiming race that drew 12 entrants plus three also-eligibles. 

The race is the fifth leg of the Rainbow Pick 6 at Gulfstream Park, which begins with Race 6 at 5:25 p.m. ET and ends with Race 10. Racing insider and accomplished horseplayer Bob Weir has handicapped each of the races in the Pick 6, and with Sunday being a mandatory-payout day, you'll want to see his horse racing predictions and best bets before building any Rainbow 6 picks at Gulfstream Park for Sunday, April 19.

Based in Saratoga Springs, N.Y., Weir has been handicapping and following horse racing since reading Andy Beyer's landmark handicapping book "Picking Winners" in the late 1980s. Weir is highly invested in the Beyer speed figure, a number assigned to every race run by a horse that measures how fast the horse ran. He uses the figure as the backbone of his handicapping. In fact, thanks to his proficiency with speed figures and top-tier handicapping, he landed one of just eight spots on Beyer's figure-making team in 2017, a position he holds to this day.

Weir's methodology has produced multiple five-figure days. In 2014, he hit a $60,000 Pick 6 at Del Mar on a $144 ticket. The following year, he nailed a $31,000 Pick 6 at Gulfstream Park on a $36 investment. In 2016 and 2017, Weir qualified for the prestigious National Horseplayers Championship in Las Vegas.

And this year, his first for SportsLine, Weir has been on fire on his horse racing picks. In January he crushed the Pegasus World Cup, giving out an $8 exacta and a $1 trifecta, winning $757.60. In February's Sam F. Davis Stakes, he gave out the $.50 superfecta, which paid $150.75. Last month Weir correctly pegged Wells Bayou to win the Louisiana Derby. And he nailed the late Pick 4 at Gulfstream Park on both Thursday and Friday of last week, hitting for $827.65 and $394.65, respectively.

Now, Weir has handicapped the Rainbow Pick 6 at Gulfstream Park on Sunday, made his picks and constructed his best bets. You can head here to see them.

Top Gulfstream Park Rainbow Pick 6 predictions for April 19

Weir is high on Makisupa, an 8-1 long shot in Race 11, the final leg of the Rainbow Pick 6. This 3-year-old daughter of Muhaarar finished fifth in her only career start, a 1 1/16-mile turf race on March 8. In that race, she rallied strongly, losing by just 2.5 lengths after once trailing by 10 lengths.

Makisupa is trained by David Fawkes, who excels with second-time starters, winning at 24 percent. "Any improvement gives her a solid chance," Weir told SportsLine. 

Weir also is high on Blakey, a 6-1 long shot in Race 9, the fourth leg of the sequence. This 5-year-old gelded son of Pioneerof the Nile has three wins, five seconds and three thirds in 21 career starts. He is coming off a four-plus length win in a claiming race at Gulfstream Park on March 26.

Blakey has the early speed to set the pace on Sunday. "[He] comes off a win against lesser but could be the controlling speed under jockey Luis Saez," Weir added. 

How to make Gulfstream Park Rainbow Pick 6 selections for April 19

In addition, Weir is high on a double-digit long shot on Sunday. This horse closed into a slow pace in her last start, but "if there is a reasonable pace [on Sunday], expect an improved performance," he said. This horse could light up the tote board and spice up the Rainbow Pick 6. He's sharing his full Rainbow Pick 6 grid only at SportsLine.

How has Weir constructed his Rainbow Pick 6 ticket for Sunday? And which double-digit long shot can win at a big price? Visit SportsLine to see Weir's picks for the Rainbow Pick 6 at Gulfstream Park on Sunday, and find out.