There isn't a great fundamental backdrop for the US dollar today. Economic data has been lackluster and Treasury yields are relatively stable, up 1.5-2.9 bps across the curve. The dip in equities provides some support but it's within a narrow range.
Yet EUR/USD is down nearly 100 pips from early European trade and cable is also under heavy pressure. That selling is coming ahead of the London fix and Citi has warned about strong USD-positive flows into month end.
The dollar-buying has more recently spread to the commodity currencies and that's a factor to watch. Oil is still higher on the day but has given back some gains as the mood sours.
In terms of the charts, EUR/USD tried to break out of the recent range to the upside yesterday but faded late. If it breaks 1.0500 then 1.0472 was the June 22 low. Watch for a reversal after the fix or the London close at 1600 GMT.