Unfortunately your team has several hundred problems. Some are easy to fix some will come at a cost. Your main problem is synergy. You have 5 Pokémon weak to water for a start and I wouldn't put any bets on Alakazam taking a Choice specs Hydro Pump from a Politoed.
See these two on a team and it is as good as game over
252Atk Mamoswine (Neutral) Ice Shard vs 252HP/184Def Gliscor (Neutral): 54% - 64% (192 - 228 HP). Guaranteed 2HKO. But is it? After two turns of healing (After a protect) Gliscor has received 25% of its health back meaning you would have to hit Ice shard for maximum damage 2x in a row for a clean ko. The chances of that are slim and like a Gliscor would stay in anyway, risking taking a Icicle Crash.
Each time Mamo switch's in to scare Mamo out he takes 25% from rocks with more possibly to come from spikes. You need another solid counter so Gliscor does not wall 99% of your team. Yes I left Muscle Band out of the calculation it is outclassed on the Mamo.
If you want to win the weather war you need to be bulky which is generally why Ninetails sucks as a weather inducer. You want to be bulky as you need to come in many times and possibly take many hits. That is why Politoed is so effective. Tyranitar may be bulky but it can be dealt with very easy.
Below is Pokémon Online usage for Ou in November. It is a bit different to Smogons (or what you use on Showdwon) but it is generally the same top threats. 80% of the top 15 used can take out your current Tyranitar in one move.
1 - Scizor (18.62 %) Bug Bite, U-turn, Bullet Punch
2 - Politoed (16.76 %) Hydro Pump, Scald, Surf
3 - Dragonite (16.28 %) Superpower, Waterfall
4 - Ferrothorn (14.31 %) Gyro Ball, Power Whip, Leech Seed stallin
5 - Tyranitar (13.67 %) Superpower
6 - Heatran (13.02 %) Not a threat
7 - Jirachi (12.28 %) Iron Head
8 - Rotom-W (12.25 %) Hydro Pump
9 - Gengar (11.97 %) Focus Blast
10 - Genesect (11.89 %) Iron Head, U-turn, Bug Buzz
11 - Terrakion (11.40 %) Close Combat
12 - Gliscor (10.87 %) Toxic Stall, Earthquake
13 - Breloom (10.05 %) Mach Punch, Drain Punch
14 - Latios (9.27 %) Not a threat
15 - Tentacruel (8.89 %) Not a major threat
Above is what Tyranitar is up against. We need to change the set so these threats are narrowed down as well as an attempt to win the weather war.
Sand Stream | Sassy | 252 Hp / 4 Atk / 252 Sdef
Pursuit | Ice Beam | Fire Blast | Stealth Rock
This set is great. You can take numerous special hits with its 492 Sdef (when taking the sand boost into account) Meaning Pokémon like standard Starmie fail to even 3hko (sometimes) with Surf. Fire Blast hits Pokémon like Ferrothorn attempting to wall you and Ice Beam hits Gliscor or other Pokémon trying to get the switch in such as Landorus-T.
Pursuit does not hit as hard as Crunch but traps Pokemon like Latios and Latias or any Pokémon really that is forced to switch.
Your not exactly abusing its scarf if your not going to invest in speed. With your current set it is running only 10 more speed points than it would at max speed with no scarf.
For that reason we need to change the set. But I'm not going to because Heatran offers nothing to the team apart from a whole lot more of problems synergy wise.
Levitate | Calm | 248 Hp / 28 Satk / 232 Sdef
Volt Switch | Hydro Pump | Wil-O-Wisp | Pain Split
This guy fixes up your Mamo/Gliscor/Rain team problem
Hp Ice>Energy Ball
Give it a Choice Band it hits 1.5x harder :3
Give it a Choice Scarf unless you want to run a double dance set but they usually fail 50% of the time.
What is this set doing lol Lets just quickly put this into a situation. You have 2 Pokémon left. Alakazam and Gliscor Gliscor sets up 3 Swords Dances and baton Passes to Alakazam.
Alakazam remembers it doesn't have any physical moves and nor any physical def. Gliscor is forced to try and PP stall the rest of the battle.
Honestly the set kind of sucks, sorry. Just use the standard toxic stall set, though I prefer this set.
Poison Heal | Impish | 252 Hp / 184 Def / 72 Speed
Swords Dance | Protect | Ice Fang | Earthquake
This set is great and serves the role of a tank/sweeper or Defensive wall. A defensive Wall that is much needed.
O.o This took longer than expected danm intro. ;) anyway these changes should help fix some problems regarding sets and synergy but you still are vulnerable to rain teams and other threats though there is only so much I can change before the team becomes mine not yours. Rotom should fix a lot of problems for the most part though.
So hope this helps