US Cash Crude-Grades mixed as traders return from long holiday weekend

April 22 (Reuters) - U.S. sweet crude grades weakened on Tuesday while West Texas Sour also slipped, dealers said, as the front-month futures contract expired and kicked off a more volatile trading period.

Light Louisiana Sweet WTC-LLS for May delivery weakened 20 cents at a midpoint of a $2.00 premium to U.S. West Texas Intermediate futures CLc1, the weakest in nearly a month. WTI Midland WTC-WTM, another sweet grade, weakened 10 cents at a midpoint of a 80-cent premium, its weakest since January.

West Texas Sour WTC-WTS weakened 30 cents at a midpoint of a 70-cent discount. Mars Sour WTC-MRS strengthened 15 cents at a midpoint of a $1.35 premium

U.S. crude futures' discount to the international benchmark Brent WTCLc1-LCOc1 narrowed on Tuesday to as much as $3.67 a barrel on the contract expiry.

A narrower discount typically weakens demand for U.S. crude grades.

U.S. crude stocks fell by 4.6 million barrels in the week ended April 18, market sources said, citing American Petroleum Institute figures on Tuesday.

Light Louisiana Sweet WTC-LLS for May delivery weakened 20 cents at a midpoint of a $2.00 premium and was seen bid and offered between a $1.80 and $2.20 a barrel premium to U.S. crude futures CLc1

Mars Sour WTC-MRS strengthened 15 cents at a midpoint of a $1.35 premium and was seen bid and offered between a $1.25 and $1.45 a barrel premium to U.S. crude futures CLc1

WTI Midland WTC-WTM weakened 10 cents at a midpoint of a 80-cent premium and was seen bid and offered between a 70-cent and 90-cent a barrel premium to U.S. crude futures CLc1

West Texas Sour WTC-WTS weakened 30 cents at a midpoint of a 70-cent discount and was seen bid and offered between a 80-cent and 60-cent a barrel discount to U.S. crude futures CLc1

WTI at East Houston WTC-MEH, also known as MEH, traded between a $1.05 and $1.25 a barrel premium to U.S. crude futures CLc1

ICE Brent June futures LCOc1 rose $1.18 to settle at $67.44 a barrel

WTI May crude CLc1 futures rose $1.23 to settle at $64.31 a barrel

The Brent/WTI spread WTCLc1-LCOc1 narrowed last to trade at minus $3.78, after hitting a high of minus $3.67 and a low of minus $3.83