Try turning your laptop in a different orientation or move it from that position. Most laptops have their antenna in the display because it is normally vertically oriented. Hence the better signal quality.
When the cover is flat it is probably in line with the signal source which reduces the effectiveness of signal reception. You could try propping up the laptop; even if it is at a 15 degree angle will help with signal quality.
The antennas are fairly blocked by the metal of the lid and base when the lid is closed. They really only have the plastic part of the hinge to get any signal out of if the laptop is not open.
See the two black rectangles behind the screen.
Depending on many factors such as frequency 2.4 or 5GHz, access point placement, obstructions, other access points in the area you may see small or large drops in performance.