A few scenarios could mean "a cold shower" for investors, Mike Santoli of Yahoo! Finance said Friday.

"I think the market's reasonably well supported. I'm not saying run for the hills," he said, adding that optimism in the stock market leaves investors "over-susceptible to any disturbance in the good news."

On "Fast Money,"Santoli identified three pullback triggers:

• Sequester takes effect
  
• Citi Surprise Index falls further
  
• Earnings season
  

Santoli urged caution regarding negotiations over raising the federal debt ceiling.

"I do think we'd have a little bit of a cold shower if we're looking at the economic growth forecasts that involve major cuts, whether its sequestration, whether it is a short-term government shutdown," he said.

"I'm not alarmist about what's going on in D.C., but I feel like what we're done is, the consensus has really been oscillating between over-anticipating terrible things from D.C. to under-anticipating them, and I think we're in the latter situation right now."

Trader disclosure: On Jan. 18, 2013, the following stocks and commodities mentioned or intended to be mentioned on CNBC's "Fast Money" were owned by the "Fast Money" traders: Steve Weiss is long SCCO; Steve Weiss is long CNX; Steve Weiss is long RIMM; Steve Weiss is long T; Jon Najarian is long MS CALL SPREADS; Jon Najarian is long AMAT CALL SPREADS; Jon Najarian is long ATE; Jon Najarian is long NANO; Jon Najarian is long TWI CALL SPREADS; Pete Najarian is long AAPL; Pete Najarian is long BAC CALLS; Pete Najarian is long GS CALLS; Pete Najarian is long JPM CALLS; Pete Najarian is long RIMM; Pete Najarian is long SBUX; Pete Najarian is long SBUX CALLS; Pete Najarian is long FB; Pete Najarian is long MSFT; Pete Najarian is long GE; Joe Terranova is long VRTS; Joe Terranova is long AAPL; Joe Terranova is long GS; Joe Terranova is long AXP; Joe Terranova is long MS; Joe Terranova is long GLW; Joe Terranova is long DELL; Joe Terranova is long MMM; Joe Terranova is long SWN; Joe Terranova is long XOM.