CAPE CANAVERAL — An Atlas V rocket is poised for launch on its Cape Canaveral pad today, but the forecast for the planned launch Tuesday of a military mini-shuttle is not favorable.

The United Launch Alliance rocket and an Air Force X-37B spacecraft are scheduled to blast off at 1:03 p.m. Tuesday at Cape Canaveral Air Force Station’s Launch Complex 41.

The launch window extends through 6:03 p.m.

However, a cold front is expected to sweep into central Florida Tuesday, bringing with it a high probability of cloudy conditions, rain showers and isolated thunderstorms.

Air Force meteorologists say there is a 70 percent chance conditions would prohibit a launch Tuesday.

The weather forecast for Wednesday is the same. The front is expected to stall over central Florida Wednesday before moving off to the northeast.

Mounted atop a mobile launch platform, the Atlas V and its payload moved out of its 30-story assembly building today and made the 1,800-foot trip to the launch pad along rail tracks. Two specially designed “trackmobiles” transported the rocket to the pad.

The launch of the X-37B will be the first re-flight of one of the experimental spaceplanes. The vehicle was launched in April 2010 on a 224-day technology demonstration mission, the exact nature of which remains classified.

A second X-37B spacecraft launched in March 2011 and flew a 469-day mission.

The X-37B is capable of autonomous atmospheric reentry and landing, and the first two missions concluded on a runway at Vandenberg Air Force Base in California.

Air Force officials say there is a chance the third mission will culminate with a landing on the shuttle runway at NASA’s Kennedy Space Center.

The service also is considering consolidating X-37B launch, landing and turn-around operations on Florida’s Space Coast.