An example of ionospheric propagation modes, based in Dubai, UAE.

(click on image to zoom in, use "back" to return to this page from zoom in)

This is a snapshot of IPS predictions for the region of Dubai, UAE. As you can see, the whole mainland US is out of HF reach in any band, mainly due to enormous D layer absorption. Normally, a long wavelenght band would allow for contact, but the D layer daytime absorption rises the Absorption limiting frequency (ALF) in day area above the relevant MUF at dark areas. Thus, no communication can be established at any frequency.

here is the F0F2 global map on snapshot time.