Difference between Ominous and Alarming

OMINOUS vs ALARMING: ADJECTIVE

Specifically, giving indication of a coming ill; being an evil omen; threatening; portentous; inauspicious.
Of or pertaining to an omen or to omens; being or exhibiting an omen; significant; portentous; -- formerly used both in a favorable and unfavorable sense; now chiefly in the latter; foreboding or foreshowing evil; inauspicious.
Of or being an omen, especially an evil one.
Menacing; threatening.
Threatening or foreshadowing evil or tragic developments
Presaging ill-fortune

Frightening because of an awareness of danger
Causing apprehension, fear or alarm; frightening
Exciting, or calculated to excite, alarm; causing apprehension of danger. -- A*larm"ing*ly, adv.
Causing alarm or fear

Of ill omen; giving indication of coming ill; portentous; inauspicious; unlucky.
Of good omen; auspicious.
Conveying some omen; serving as a sign or token; significant.

Eerie, Grim, Unsettling, Minacious, Ill, Forbidding, Threatening, Unpropitious, Minatory, Ugly, Inauspicious, Baleful, Sinister, Alarming, Menacing

Ghastly, Horrific, Dreadful, Terrifying, Chilling, Grim, Scary, Horrendous, Dire, Dismaying, Unnerving, Horrifying, Ominous, Appalling, Frightening

Eerie, Grim, Unsettling, Minacious, Ill, Forbidding, Threatening, Unpropitious, Minatory, Ugly, Inauspicious, Baleful, Sinister, Alarming, Menacing

Ghastly, Horrific, Dreadful, Terrifying, Chilling, Grim, Scary, Horrendous, Dire, Dismaying, Unnerving, Horrifying, Ominous, Appalling, Frightening

But almost immediately they ran into ominous opposition.
There was nothing but ominous silence from Kolanse.
SYN: Predictive, ominous, portentous, premonitory, fatidical, oracular, sibylline.
The reports produced by these teams were ominous.
The chiefs had regarded that as particularly ominous.
Lena notices other, ominous signs, though, and sheworries.
One other resignation had even more ominous overtones.
This evasion, however, is the less ominous option.
Polyhydramnios and fetal intrauterine growth restriction: ominous combination.
We heard an ominous hiss from the kitchen.

But for me, it is an alarming indicator.
Losing your child is actually a alarming prospect.
Online porn is growing at an alarming amount.
Google search also would have yielded alarming results.
Corso says conversion cases are the most alarming.
Budget data revealed an alarming state of affairs.
Other reports followed, still more emphatic and alarming.
This was very surprising and alarming to us.
It was alarming to suppose that that thing was perhaps dead; and still more alarming to think that it was perhaps alive.
Alarming as thmore alarming still are the transboundry economical dependencies they create.