US Cash Crude-WTI Midland falls to 2-1/2-year low, medium sour grades firm

June 13 (Reuters) - WTI Midland differentials to crude oil at the Cushing storage hub weakened to its lowest in two and a half years on Friday, dealers said, as tight inventories and worries about geopolitical tensions strengthened prices at the hub.

WTI Midland WTC-WTM eased to a 35-cent premium to oil at Cushing, while WTI at East Houston WTC-MEH, also known as MEH, fell to a 45-cent premium.

Wildfires in Canada are expected to tighten inventories at Cushing in June, analysts said.

The spread between WTI and Brent widened as much as minus $4.21, but was last trading around minus $2.94. A narrower spread, particularly under minus $4 cuts exports as it is less attractive for foreign buyers to purchase U.S. crude.

Medium sour grades such as Mars, SGC and Thunder Horse strengthened due to lower supply of heavy Canadian crude due to wildfires and as a period granted by Washington to wind down purchases of Venezuelan crude by U.S. companies expired in late May.

Oil prices jumped on Friday and settled 7% higher as Israel and Iran traded air strikes, feeding investor worries that the combat could widely disrupt exports from the Middle East.

* Light Louisiana Sweet WTC-LLS for July delivery gained to a midpoint of a $3.10 premium and was seen bid and offered between a $2.90 and $3.30 a barrel premium to U.S. crude futures CLc1

* Mars Sour WTC-MRS strengthened to a midpoint of a $1.90 premium and was seen bid and offered between a $1.70 and $2.10 a barrel premium to U.S. crude futures CLc1

* WTI Midland WTC-WTM eased to a midpoint of a 35-cent premium and was seen bid and offered between a 15-cent and 55-cent a barrel premium to U.S. crude futures CLc1

* West Texas Sour WTC-WTS was unchanged at a midpoint of a 15-cent discount and was seen bid and offered between a 20-cent and 10-cent a barrel discount to U.S. crude futures CLc1

* WTI at East Houston WTC-MEH, also known as MEH, traded between a 25-cent and 65-cent a barrel premium to U.S. crude futures CLc1

* ICE Brent August futures LCOc1 rose $4.87 to settle at $74.23 a barrel.

* WTI July crude CLc1 futures rose $4.94 to settle at $72.98 a barrel.

* The Brent/WTI spread WTCLc1-LCOc1 widened 22 cents to last trade at minus $2.94, after hitting a high of minus $2.72 and a low of minus $4.23.