Each of the 26 clues represents a 6-letter word. For each of those words, it is possible (in only one way) to replace the first two letters with a single letter to create a 5-letter word (“Santa’s lead reindeer has to work hard enough for two”). (The title of the puzzle is another illustration of the same mechanic.) Since there is a unique replacement for each of the 26 letters of the alphabet, this creates a cipher whereby the replacement bigram stands in for the original letter. So SU decodes to A, ED decodes to B, etc.

• CASUAL (USUAL)
• CHIRAL (VIRAL)
• CRISPY (WISPY)
• DEEPLY (REPLY)
• EDIBLE (BIBLE)
• ENNEAD (KNEAD)
• HUEBRA (ZEBRA)
• IXERBA (YERBA)
• KAYLAN (XYLAN)
• KEEPER (LEPER)
• LAYMEN (HYMEN)
• LOCALE (SCALE)
• MIRROR (ERROR)
• MYRIAD (TRIAD)
• NIECES (FECES)
• OBUASI (QUASI)
• ORDEAL (IDEAL)
• PEPTIC (OPTIC)
• PLINTH (NINTH)
• SERAPH (GRAPH)
• SHROUD (PROUD)
• SLUICE (JUICE)
• STREEP (CREEP)
• SUPPLY (APPLY)
• THIRTY (DIRTY)
• URANIA (MANIA)

Deciphering the three messages at the bottom gives the following clues:

• HERTZ OR RENT-A-WRECK RIVAL EIGHT (which is NATIONAL)
• WEAR AWAY BY EXPOSURE TO SQUALLS SEVEN (which is WEATHER)
• WORD AFTER JURY OR ROOM SEVEN (which is SERVICE)

The final answer to the puzzle is NATIONAL WEATHER SERVICE.