CHICAGO, May 21 (Reuters) - Basis bids for hard red winter wheat were mostly flat at locations around the southern U.S. Plains on Thursday on light demand and weaker futures prices, grain merchants said.

• Easing prices kept a lid on farmer sales following moderate selling last week, when prices hit multi-year highs, merchants said. Drought in many areas of the Plains wheat belt has curbed harvest prospects, further discouraging farmer sales, they said.

• Extreme drought expanded in southwestern Kansas and southern Colorado in the past week, while severe to extreme drought expanded in parts of Oklahoma, according to a weekly U.S. Drought Monitor report. About 70% of winter wheat production was affected by drought as of May 19, the data showed.

• U.S. wheat export demand remained light as cheaper grain is available from other suppliers.

• The U.S. Department of Agriculture said net old-crop U.S. wheat export sales in the week ended May 14 totaled 166,342 metric tons, while new-crop sales were 130,488 tons, in line with trade estimates. The total included just 13,854 tons in old-crop HRW wheat sales, the lowest for a single week in four months, according to USDA data.

• K.C. July hard red winter wheat KWN26 last traded 12 cents at $6.86-3/4 per bushel.

Basis values are quoted against futures in cts/bu:

	Current			Previous			Cash
	basis			basis			price
KANSAS
Wichita	-24	+	N	-24	+	N	$6.63
Newton	-49	+	N	-49	+	N	$6.38
Goodland	-90	+	N	-90	+	N	$5.97
TEXAS
Gulf track*	+120	+	N	+120	+	N	$8.07
Galveston**	+100	+	N	+100	+	N	$7.87
OKLAHOMA
Enid	-15	+	N	-15	+	N	$6.72
Catoosa	-15	+	N	-15	+	N	$6.72

NOTES:

H = March, K = May, N = July, U = September

Z = December; UNQ = Unquoted bids

0 = Spot Option price; NC = No comparison

* = No. 1 12% hard winter wheat, rail bids

** = Ordinary protein, rail bids

LINKS:

* K.C. HRW wheat protein scales KCBT/SCA

* U.S. weekly wheat crop progress US/WHE

* U.S. forward basis WHEAT/BASIS

* U.S. Midwest cash grain PM GRA/PM

* U.S. CIF Gulf Grain GRA/C

* U.S. FOB Gulf Grain GRA/F