Assalamualaikum ustaz. Is it permissible to perform jamak Friday and Asar prayer?
Alhamdulillah, praise and gratitude to Allah SWT for His countless blessings for us all. Praise and salutations to our beloved Prophet Muhammad PBUH, his family, companions and all those who follow his footsteps until the Last Day.
First, a traveller is given the choice of either performing Zohor or Friday prayer, without any one of them prioritized over the other. The reason is for a traveller, his obligation to perform the Friday prayer is abrogated. 
The exception for a traveller is based on the actions of the Prophet PBUH who didn’t perform the Friday prayer when he was travelling for hajj where the day of Arafah falls on a Friday, thus, the Prophet PBUH performed the jamak Zohor and Asar prayers. This opinion is held by jumhur of the scholars, among them is the statement made by Imam al-Nawawi in his book al-Majmu’: “The Friday prayer is not obligatory for a traveller and this is the opinion held by our madhhab.”
Second, it is permissible for a traveller to jamak his prayer, whether it is jamak taqdim or jamak takhir according to madhhab al-Syafie. However, Imam Abu Hanifah doesn’t permit jamak except for hajj. Thus, some Syafi’iyyah scholars considered it afdal (prioritized) to leave jamak to avoid the khilaf. 
Third, regarding the issue of jamak Friday and Asar prayer, scholars have two differing opinions.
- First, it is permissible. This is the opinion of Syafie scholars and is validated by Imam al-Suyuti and held by al-Zarkasyi. The same is also stated in a fatwa by Syeikh al-Ramli. Their evidence is based on the analogical deduction of Friday prayer and Zohor prayer.
- Second, it is impermissible. This is the famous opinion amongst the Hanbali and one wajah of Syafie scholars. They argued that jamak Asar to Friday is impermissible according to syarak for worship is originally built on tawaqquf (what has been commanded by Allah) and cannot be analogically deduced with anything.
I’m inclined towards the first opinion which is it is permissible to perform jamak Friday and Asar prayers for the argument is strong and there is maslahat. Moreover, it is permissible to perform jamak taqdim for Friday and Asar prayers for Friday prayer is badal (replacement) for Zohor prayer. 
In this matter, a person is more knowledgeable and understand his needs more. Thus, considering the value of samahah and tolerance in Islam, a person can fulfil the obligation of worship in any type of situation and this is prioritized.