Two officers were inside the car conducting a mobile patrol of the town when the incident occurred in the early hours of Monday.
They were leaving Pinewood Avenue at about 02:00 BST, when a man emerged from an alleyway and threw a brick at the vehicle.
The brick struck the windscreen in front of the driver, smashing it.
The man, who was dressed in a dark hooded jacket with his face covered, ran off in the direction of the alleyway.
The officers were left shaken, but physically unharmed.
Sgt Brian Caskey condemned the attack.
"This patrol vehicle will be out of circulation while repairs are carried out," he said.
"The person responsible needs to be identified and brought to justice."

Ministers are to increase the maximum discount - currently £16,000 to £38,000 - to more than the expected £50,000.
They hope it will persuade more tenants and mortgage lenders to get involved in the scheme first started in the 1980s.
But housing charity Shelter says the plans risk diminishing the stock of "genuinely affordable" social housing.
It also says the plans could saddle low-income families with mortgage debts they cannot afford.
The "right to buy" scheme was first started under Margaret Thatcher's government.
In December the government launched a consultation on "re-invigorating" the right to buy, which has dwindled in recent years, and suggested the maximum discount may be raised to £50,000.
Currently, discount levels differ across the country, ranging from £16,000 to £38,000.
Now ministers believe discounts should be as high as £75,000, the BBC understands.
The government insists all social homes that are sold "will be replaced on a one-for-one basis by a new affordable rent property, ensuring there is no reduction in the number of affordable homes".
But Shelter says it will still have the effect of damaging social housing.
Roger Harding, Shelter's head of policy, research and public affairs, said: "The government is not going to replace like-with-like.
"The 'affordable rent' model means landlords can charge rents of up to 80% of market rates, which is typically higher than council rents.
"The net result will be a reduction in the number of genuinely affordable homes for families on modest incomes."
He added: "That could have the added effect of pushing up the housing benefit bill, if there are fewer council houses and more 'affordable rent' properties with higher rental costs."
Mr Harding said: "We are also concerned that ownership is not necessarily the most financially suitable form of tenure for a lot of social housing tenants.
"Many are on very low incomes and could find themselves unable to afford the mortgage repayments. Statistically, right-to-buy mortgage holders are far more likely than other purchasers to have their homes repossessed."
Later this week Housing Minister Grant Shapps is expected to say: "This coalition government backs the dreams of those who want to own the roof over their own head."
He has promised to triple or even quadruple the discounts available to "hard-working families".
Mr Shapps will say: "New home buyers will have the satisfaction of knowing that for each property sold, we'll be aiming to replace it with a new affordable home for the record numbers left languishing on Labour's housing waiting lists.
"It's a win/win that backs aspirational council tenants whilst dealing with the legacy of Labour's record waiting lists."

West Midlands Police said there was a "sweet irony" to officers using the centre for forced entry training when it had been paid for by money paid into the Proceeds of Crime Act (POCA) fund.
The base in Aston, Birmingham was largely paid for by a £30,000 donation from the fund, police said.
Last year West Midlands Police spent £800,000 of POCA cash on projects.
The money is mainly used to fund community crime prevention projects and comes from money convicted criminals have been ordered to pay back.

The 18-year-old was found in Caldy Walk, Islington, shortly after 18:00 BST on Wednesday and died a short time later in hospital.
Two boys have been arrested on suspicion of murder and three others are being held on suspicion of robbery and perverting the course of justice.
They are all being held in custody.
A post-mortem examination gave the cause of Mr Appleton's death as a stab wound to the chest, shock and haemorrhage.
Mr Appleton was in Nightingale Park with friends when he was attacked, police said.
The windscreen of a PSNI car has been smashed during an attack on a police patrol in Carrickfergus.
[NEXT_CONCEPT]
Social housing tenants could be offered discounts of up to £75,000 under plans to increase the numbers exercising the "right to buy" their home in England.
[NEXT_CONCEPT]
Ill-gotten gains recovered from criminals have paid for a new training centre for police staff.
[NEXT_CONCEPT]
Five 16-year-old boys have been arrested in connection with the fatal stabbing of teenager Stefan Appleton in north London.