Where are you having the problem? Up in the 800 or 900 series where HD channels reside?
Have you looked for the Weather Channel (SD version) found maybe in <100 series, or 200 series. If you find it there, there might be corrosion in connections or damage to a transmission line in your neighborhood. Just certain frequences get affected under those conditions. Checking "support" for trouble-shooting for your cable-box, or calling your local service center might work better to solving the problem.